Provided by: zsh_4.3.4-24ubuntu1_i386 bug

NAME

       zshcompsys - zsh completion system

DESCRIPTION

       This describes the shell code for the ‘new’ completion system, referred
       to as compsys.  It is written in shell functions based on the  features
       described in zshcompwid(1).

       The features are contextual, sensitive to the point at which completion
       is started.  Many completions are already provided.  For this reason, a
       user  can perform a great many tasks without knowing any details beyond
       how  to  initialize  the  system,   which   is   described   below   in
       INITIALIZATION.

       The context that decides what completion is to be performed may be
       ·      an  argument  or option position: these describe the position on
              the command line at which completion is requested.  For  example
              ‘first  argument  to  rmdir,  the  word  being completed names a
              directory’;

       ·      a special context, denoting an element in  the  shell’s  syntax.
              For   example   ‘a  word  in  command  position’  or  ‘an  array
              subscript’.

       A full context specification  contains  other  elements,  as  we  shall
       describe.

       Besides  commands  names  and  contexts,  the  system  employs two more
       concepts, styles  and  tags.   These  provide  ways  for  the  user  to
       configure the system’s behaviour.

       Tags  play  a dual role.  They serve as a classification system for the
       matches, typically indicating a class of object that the user may  need
       to  distinguish.   For  example,  when  completing  arguments of the ls
       command the user may prefer to try files before directories, so both of
       these are tags.  They also appear as the rightmost element in a context
       specification.

       Styles modify various operations of  the  completion  system,  such  as
       output  formatting,  but also what kinds of completers are used (and in
       what order), or which tags are examined.  Styles may  accept  arguments
       and   are  manipulated  using  the  zstyle  command  described  in  see
       zshmodules(1).

       In summary, tags describe what the completion objects  are,  and  style
       how  they  are  to  be  completed.  At various points of execution, the
       completion system checks what styles and/or tags are  defined  for  the
       current  context,  and  uses  that  to  modify  its behavior.  The full
       description of context handling, which determines how  tags  and  other
       elements of the context influence the behaviour of styles, is described
       below in COMPLETION SYSTEM CONFIGURATION.

       When a completion is requested, a dispatcher function  is  called;  see
       the  description  of  _main_complete  in  the list of control functions
       below. This dispatcher decides  which  function  should  be  called  to
       produce  the  completions, and calls it. The result is passed to one or
       more  completers,  functions  that  implement   individual   completion
       strategies:  simple completion, error correction, completion with error
       correction, menu selection, etc.

       More generally, the shell functions contained in the completion  system
       are of two types:
       ·      those beginning ‘comp’ are to be called directly; there are only
              a few of these;

       ·      those beginning ‘_’ are called  by  the  completion  code.   The
              shell   functions   of  this  set,  which  implement  completion
              behaviour and may be bound to keystrokes,  are  referred  to  as
              ‘widgets’.  These proliferate as new completions are required.

INITIALIZATION

       If the system was installed completely, it should be enough to call the
       shell function compinit from your initialization  file;  see  the  next
       section.   However,  the  function  compinstall can be run by a user to
       configure various aspects of the completion system.

       Usually, compinstall will insert code into .zshrc, although if that  is
       not  writable  it will save it in another file and tell you that file’s
       location.  Note that it is up to you to make sure that the lines  added
       to  .zshrc are actually run; you may, for example, need to move them to
       an earlier place in the file if .zshrc usually returns early.  So  long
       as you keep them all together (including the comment lines at the start
       and finish), you can rerun compinstall and it will correctly locate and
       modify  these  lines.   Note,  however,  that  any code you add to this
       section by hand is likely to be lost if you rerun compinstall, although
       lines using the command ‘zstyle’ should be gracefully handled.

       The  new  code  will  take effect next time you start the shell, or run
       .zshrc by hand; there is also  an  option  to  make  them  take  effect
       immediately.  However, if compinstall has removed definitions, you will
       need to restart the shell to see the changes.

       To run compinstall you will need to make sure  it  is  in  a  directory
       mentioned  in your fpath parameter, which should already be the case if
       zsh was properly configured as long as your startup files do not remove
       the  appropriate  directories  from  fpath.  Then it must be autoloaded
       (‘autoload  -U  compinstall’  is  recommended).   You  can  abort   the
       installation  any time you are being prompted for information, and your
       .zshrc will not be altered at all; changes only take place right at the
       end, where you are specifically asked for confirmation.

   Use of compinit
       This section describes the use of compinit to initialize completion for
       the current session when called directly; if you have  run  compinstall
       it will be called automatically from your .zshrc.

       To  initialize  the  system,  the  function  compinit  should  be  in a
       directory mentioned in the fpath parameter, and  should  be  autoloaded
       (‘autoload  -U  compinit’  is  recommended),  and  then  run  simply as
       ‘compinit’.  This will define a few utility functions, arrange for  all
       the necessary shell functions to be autoloaded, and will then re-define
       all widgets that do completion to use the new system.  If you  use  the
       menu-select  widget,  which  is  part  of  the zsh/complist module, you
       should make sure that that module is loaded before the call to compinit
       so  that  that  widget  is  also re-defined.  If completion styles (see
       below) are set up  to  perform  expansion  as  well  as  completion  by
       default,  and the TAB key is bound to expand-or-complete, compinit will
       rebind it to complete-word; this is necessary to use the  correct  form
       of expansion.

       Should  you need to use the original completion commands, you can still
       bind keys to the old widgets by putting a ‘.’ in front  of  the  widget
       name, e.g. ‘.expand-or-complete’.

       To speed up the running of compinit, it can be made to produce a dumped
       configuration that will be read in on future invocations; this  is  the
       default,  but can be turned off by calling compinit with the option -D.
       The dumped file is .zcompdump in the  same  directory  as  the  startup
       files  (i.e.  $ZDOTDIR  or $HOME); alternatively, an explicit file name
       can be given  by  ‘compinit  -d  dumpfile’.   The  next  invocation  of
       compinit  will  read  the  dumped  file  instead  of  performing a full
       initialization.

       If the number of completion files changes, compinit will recognise this
       and produce a new dump file.  However, if the name of a function or the
       arguments in the first line of a #compdef function (as described below)
       change,  it is easiest to delete the dump file by hand so that compinit
       will re-create it the next time it is run.  The check performed to  see
       if  there are new functions can be omitted by giving the option -C.  In
       this case the dump file  will  only  be  created  if  there  isn’t  one
       already.

       The  dumping  is  actually  done by another function, compdump, but you
       will only need to run this yourself if  you  change  the  configuration
       (e.g.  using  compdef)  and then want to dump the new one.  The name of
       the old dumped file will be remembered for this purpose.

       If the parameter _compdir is set, compinit uses it as a directory where
       completion  functions  can be found; this is only necessary if they are
       not already in the function search path.

       For security reasons compinit also  checks  if  the  completion  system
       would  use  files not owned by root or by the current user, or files in
       directories that are world- or group-writable or that are not owned  by
       root  or  by the current user.  If such files or directories are found,
       compinit will ask if the completion system should really be  used.   To
       avoid  these tests and make all files found be used without asking, use
       the option -u, and to make compinit silently ignore all insecure  files
       and  directories  use  the  option  -i.  This security check is skipped
       entirely when the -C option is given.

       The security check can be retried at any time by running  the  function
       compaudit.   This  is  the  same check used by compinit, but when it is
       executed directly any changes to fpath are made local to  the  function
       so they do not persist.  The directories to be checked may be passed as
       arguments; if none are given, compaudit uses fpath and _compdir to find
       completion   system  directories,  adding  missing  ones  to  fpath  as
       necessary.  To force a check of exactly the directories currently named
       in  fpath,  set _compdir to an empty string before calling compaudit or
       compinit.

   Autoloaded files
       The convention for autoloaded functions used in completion is that they
       start  with  an  underscore;  as  already  mentioned,  the  fpath/FPATH
       parameter must contain the directory in which they are stored.  If  zsh
       was  properly  installed on your system, then fpath/FPATH automatically
       contains the required directories for the standard functions.

       For incomplete installations, if compinit does not  find  enough  files
       beginning with an underscore (fewer than twenty) in the search path, it
       will try to find more by adding the directory _compdir  to  the  search
       path.    If   that   directory  has  a  subdirectory  named  Base,  all
       subdirectories  will  be  added  to  the  path.   Furthermore,  if  the
       subdirectory  Base has a subdirectory named Core, compinit will add all
       subdirectories of the subdirectories is to the path:  this  allows  the
       functions to be in the same format as in the zsh source distribution.

       When  compinit  is  run,  it  searches  all  such  files accessible via
       fpath/FPATH and reads the first line of each of them.  This line should
       contain  one  of the tags described below.  Files whose first line does
       not start with one of these tags are not considered to be part  of  the
       completion system and will not be treated specially.

       The tags are:

       #compdef names... [ -[pP] patterns... [ -N names... ] ]
              The  file  will be made autoloadable and the function defined in
              it will be called when completing names, each of which is either
              the name of a command whose arguments are to be completed or one
              of a number of special contexts in the form -context-  described
              below.

              Each   name  may  also  be  of  the  form  ‘cmd=service’.   When
              completing the command cmd, the function typically behaves as if
              the  command  (or  special  context) service was being completed
              instead.  This provides a  way  of  altering  the  behaviour  of
              functions  that  can  perform many different completions.  It is
              implemented by setting the parameter $service when  calling  the
              function;  the  function  may  choose  to  interpret this how it
              wishes, and simpler functions will probably ignore it.

              If the #compdef line contains one of the options -p or  -P,  the
              words  following are taken to be patterns.  The function will be
              called when completion is attempted for  a  command  or  context
              that  matches  one  of  the patterns.  The options -p and -P are
              used to specify patterns to  be  tried  before  or  after  other
              completions  respectively.   Hence  -P  may  be  used to specify
              default actions.

              The option -N is used after  a  list  following  -p  or  -P;  it
              specifies that remaining words no longer define patterns.  It is
              possible to toggle between the three options as  many  times  as
              necessary.

       #compdef -k style key-sequences...
              This  option  creates  a widget behaving like the builtin widget
              style and binds it to the  given  key-sequences,  if  any.   The
              style   must   be  one  of  the  builtin  widgets  that  perform
              completion,    namely    complete-word,     delete-char-or-list,
              expand-or-complete,   expand-or-complete-prefix,   list-choices,
              menu-complete,            menu-expand-or-complete,            or
              reverse-menu-complete.   If  the  zsh/complist  module is loaded
              (see zshmodules(1)) the widget menu-select is also available.

              When one of the key-sequences is typed, the function in the file
              will  be  invoked to generate the matches.  Note that a key will
              not be re-bound if if it already was  (that  is,  was  bound  to
              something other than undefined-key).  The widget created has the
              same name as the file and can be bound to any other  keys  using
              bindkey as usual.

       #compdef -K widget-name style key-sequences ...
              This  is  similar  to  -k  except  that  only  one key-sequences
              argument may be given for each widget-name style pair.  However,
              the  entire  set  of  three  arguments  may  be  repeated with a
              different  set  of  arguments.   Note  in  particular  that  the
              widget-name  must be distinct in each set.  If it does not begin
              with ‘_’ this will be added.  The widget-name should  not  clash
              with the name of any existing widget: names based on the name of
              the function are most useful.  For example,

                     #compdef -K _foo_complete complete-word "^X^C" \
                       _foo_list list-choices "^X^D"

              (all on one line) defines a widget _foo_complete for completion,
              bound  to  ‘^X^C’,  and a widget _foo_list for listing, bound to
              ‘^X^D’.

       #autoload [ options ]
              Functions with the #autoload tag are marked for autoloading  but
              are  not  otherwise treated specially.  Typically they are to be
              called from within one of the completion functions.  Any options
              supplied  will  be passed to the autoload builtin; a typical use
              is +X to force the function to be loaded immediately.  Note that
              the -U and -z flags are always added implicitly.

       The  #  is part of the tag name and no white space is allowed after it.
       The #compdef tags use the compdef function described  below;  the  main
       difference is that the name of the function is supplied implicitly.

       The special contexts for which completion functions can be defined are:

       -array-value-
              The right hand side of an array-assignment (‘foo=(...)’)

       -brace-parameter-
              The name of a parameter expansion within braces (‘${...}’)

       -assign-parameter-
              The name of a parameter in an assignment, i.e. on the left  hand
              side of an ‘=-command-
              A word in command position

       -condition-
              A word inside a condition (‘[[...]]’)

       -default-
              Any word for which no other completion is defined

       -equal-
              A word beginning with an equals sign

       -first-
              This  is  tried  before  any  other  completion  function.   The
              function called may  set  the  _compskip  parameter  to  one  of
              various  values:  all:  no  further  completion  is attempted; a
              string containing the substring patterns: no pattern  completion
              functions  will  be  called;  a  string  containing default: the
              function for the ‘-default-’ context will  not  be  called,  but
              functions defined for commands will

       -math- Inside mathematical contexts, such as ‘((...))-parameter-
              The name of a parameter expansion (‘$...’)

       -redirect-
              The word after a redirection operator.

       -subscript-
              The contents of a parameter subscript.

       -tilde-
              After  an initial tilde (‘~’), but before the first slash in the
              word.

       -value-
              On the right hand side of an assignment.

       Default implementations are supplied for each of  these  contexts.   In
       most  cases  the  context  -context-  is implemented by a corresponding
       function _context, for example the context ‘-tilde-’ and  the  function
       ‘_tilde’).

       The  contexts  -redirect-  and  -value-  allow  extra  context-specific
       information.  (Internally, this is handled by the  functions  for  each
       context  calling  the  function  _dispatch.)   The extra information is
       added separated by commas.

       For the -redirect- context,  the  extra  information  is  in  the  form
       ‘-redirect-,op,command’,  where  op  is  the  redirection  operator and
       command is the name of the command on the line.  If there is no command
       on the line yet, the command field will be empty.

       For the -value- context, the form is ‘-value-,name,command’, where name
       is the  name  of  the  parameter.   In  the  case  of  elements  of  an
       associative  array, for example ‘assoc=(key <TAB>’, name is expanded to
       ‘name-key’.  In certain special  contexts,  such  as  completing  after
       ‘make  CFLAGS=’,  the  command part gives the name of the command, here
       make; otherwise it is empty.

       It is not  necessary  to  define  fully  specific  completions  as  the
       functions  provided  will  try to generate completions by progressively
       replacing the elements with ‘-default-’.  For example, when  completing
       after  ‘foo=<TAB>’,  _value will try the names ‘-value-,foo,’ (note the
       empty          command          part),          ‘-value-,foo,-default-’
       and‘-value-,-default-,-default-’,  in  that  order,  until  it  finds a
       function to handle the context.

       As an example:

              compdef_files -g "*.log"’ ’-redirect-,2>,-default-’

       completes files matching ‘*.log’ after ‘2> <TAB>’ for any command  with
       no more specific handler defined.

       Also:


              compdef _foo -value-,-default-,-default-
       specifies  that  _foo provides completions for the values of parameters
       for which no special  function  has  been  defined.   This  is  usually
       handled by the function _value itself.

       The  same  lookup  rules  are used when looking up styles (as described
       below); for example

              zstyle:completion:*:*:-redirect-,2>,*:*file-patterns*.log’

       is another way to make  completion  after  ‘2>  <TAB>’  complete  files
       matching ‘*.log’.

   Functions
       The  following  function  is  defined  by  compinit  and  may be called
       directly.

       compdef [ -an ] function names... [ -[pP] patterns... [ -N names... ] ]
       compdef -d names...
       compdef -k [ -an ] function style key-sequences...
       compdef -K [ -an ] function name style key-sequences ...
              The first form defines the function to call  for  completion  in
              the given contexts as described for the #compdef tag above.

              Alternatively,   all   the   arguments   may   have   the   form
              ‘cmd=service’.  Here service should already have been defined by
              ‘cmd1=service’ lines in #compdef files, as described above.  The
              argument for cmd will be completed in the same way as service.

              The function argument may alternatively be a  string  containing
              any  shell  code.   The  string  will be executed using the eval
              builtin command to generate completions.  This provides a way of
              avoiding  having  to  define  a  new  completion  function.  For
              example, to complete files ending in ‘.h’ as  arguments  to  the
              command foo:

                     compdef_files -g "*.h"foo

              The  option  -n prevents any completions already defined for the
              command or context from being overwritten.

              The option -d deletes any completion defined for the command  or
              contexts listed.

              The  names  may  also contain -p, -P and -N options as described
              for the #compdef tag.   The  effect  on  the  argument  list  is
              identical,  switching  between  definitions  of  patterns  tried
              initially, patterns  tried  finally,  and  normal  commands  and
              contexts.

              The  parameter $_compskip may be set by any function defined for
              a pattern context.  If it is  set  to  a  value  containing  the
              substring  ‘patterns’  none  of  the  pattern-functions  will be
              called; if it is set to a value containing the substring  ‘all’,
              no other function will be called.

              The  form  with  -k  defines  a widget with the same name as the
              function that will be called for each of the key-sequences; this
              is  like  the #compdef -k tag.  The function should generate the
              completions needed and will otherwise behave  like  the  builtin
              widget  whose  name is given as the style argument.  The widgets
              usable  for  this   are:   complete-word,   delete-char-or-list,
              expand-or-complete,   expand-or-complete-prefix,   list-choices,
              menu-complete,           menu-expand-or-complete,            and
              reverse-menu-complete,   as   well   as   menu-select   if   the
              zsh/complist module is loaded.  The option -n prevents  the  key
              being  bound  if  it is already to bound to something other than
              undefined-key.

              The form with -K is similar and defines multiple  widgets  based
              on  the  same  function, each of which requires the set of three
              arguments name, style and key-sequences, where  the  latter  two
              are  as  for  -k  and  the  first  must  be a unique widget name
              beginning with an underscore.

              Wherever  applicable,  the  -a   option   makes   the   function
              autoloadable, equivalent to autoload -U function.

       The  function  compdef  can  be  used  to associate existing completion
       functions with new commands.  For example,

              compdef _pids foo

       uses the function _pids to complete process IDs for the command foo.

       Note also the _gnu_generic function described below, which can be  used
       to complete options for commands that understand the ‘--help’ option.

COMPLETION SYSTEM CONFIGURATION

       This section gives a short overview of how the completion system works,
       and then more detail on how users can configure how  and  when  matches
       are generated.

   Overview
       When  completion  is  attempted  somewhere  on  the  command  line  the
       completion system first works out the context.  This takes account of a
       number  of  things including the command word (such as ‘grep’ or ‘zsh’)
       and options to which the current word may be an argument (such  as  the
       ‘-o’ option to zsh which takes a shell option as an argument).

       This  context  information  is  condensed  into  a string consisting of
       multiple fields  separated  by  colons,  referred  to  simply  as  ‘the
       context’  in  the remainder of the documentation.  This is used to look
       up styles, context-sensitive options that can be used to configure  the
       completion  system.   The  context  used for lookup may vary during the
       same call to the completion system.

       The context string always consists of a fixed set of fields,  separated
       by  colons  and  with  a  leading  colon  before the first, in the form
       :completion:function:completer:command:argument:tag.   These  have  the
       following meaning:

       ·      The literal string completion, saying that this style is used by
              the completion system.   This  distinguishes  the  context  from
              those used by, for example, zle widgets and ZFTP functions.

       ·      The function, if completion is called from a named widget rather
              than through the normal completion system.   Typically  this  is
              blank,  but  it is set by special widgets such as predict-on and
              the  various  functions  in  the   Widget   directory   of   the
              distribution   to  the  name  of  that  function,  often  in  an
              abbreviated form.

       ·      The completer currently active, the name of the function without
              the  leading  underscore and with other underscores converted to
              hyphens.  A ‘completer’ is in overall control of how  completion
              is  to  be  performed;  ‘complete’  is  the  simplest, but other
              completers exist to perform related tasks such as correction, or
              to  modify  the behaviour of a later completer.  See the section
              ‘Control Functions’ below for more information.

       ·      The command or a special -context-, just at it appears following
              the  #compdef tag or the compdef function.  Completion functions
              for commands that have sub-commands usually modify this field to
              contain the name of the command followed by a minus sign and the
              sub-command.  For example, the completion function for  the  cvs
              command  sets this field to cvs-add when completing arguments to
              the add subcommand.

       ·      The argument;  this  indicates  which  command  line  or  option
              argument   we   are  completing.   For  command  arguments  this
              generally takes the form argument-n, where n is  the  number  of
              the argument, and for arguments to options the form option-opt-n
              where n is the number of the argument to option  opt.   However,
              this  is  only  the  case  if  the  command  line is parsed with
              standard UNIX-style options and arguments, so  many  completions
              do not set this.

       ·      The tag.  As described previously, tags are used to discriminate
              between the types of matches a completion function can  generate
              in  a  certain context.  Any completion function may use any tag
              name it likes, but a list of  the  more  common  ones  is  given
              below.

       The  context  is  gradually put together as the functions are executed,
       starting with the main entry point, which  adds  :completion:  and  the
       function  element  if necessary.  The completer then adds the completer
       element.  The contextual  completion  adds  the  command  and  argument
       options.   Finally,  the  tag is added when the types of completion are
       known.  For example, the context name

              :completion::complete:dvips:option-o-1:files

       says that normal completion was attempted as the first argument to  the
       option -o of the command dvips:

              dvips -o ...

       and the completion function will generate filenames.

       Usually  completion  will  be  tried  for all possible tags in an order
       given by the completion function.  However,  this  can  be  altered  by
       using  the  tag-order style.  Completion is then restricted to the list
       of given tags in the given order.

       The _complete_help bindable command shows all  the  contexts  and  tags
       available  for completion at a particular point.  This provides an easy
       way of finding information for  tag-order  and  other  styles.   It  is
       described in the section ‘Bindable Commands’ below.

       Styles  determine  such  things  as  how  the  matches  are  generated,
       similarly to shell options but with much more control.  They  can  have
       any number of strings as their value.  They are defined with the zstyle
       builtin command (see zshmodules(1)).

       When looking up styles the completion system uses full  context  names,
       including  the tag.  Looking up the value of a style therefore consists
       of two things:  the context, which may be matched as a pattern, and the
       name of the style itself, which must be given exactly.

       For example, many completion functions can generate matches in a simple
       and a verbose form and use the  verbose  style  to  decide  which  form
       should be used.  To make all such functions use the verbose form, put

              zstyle:completion:*verbose yes

       in  a startup file (probably .zshrc).  This gives the verbose style the
       value yes in every context inside the completion  system,  unless  that
       context has a more specific definition.  It is best to avoid giving the
       context as  ‘*’  in  case  the  style  has  some  meaning  outside  the
       completion system.

       Many  such general purpose styles can be configured simply by using the
       compinstall function.

       A more specific example of the use of  the  verbose  style  is  by  the
       completion  for  the  kill  builtin.   If the style is set, the builtin
       lists full job texts and process command lines; otherwise it shows  the
       bare job numbers and PIDs.  To turn the style off for this use only:

              zstyle:completion:*:*:kill:*verbose no

       For  even  more  control,  the  style can use one of the tags ‘jobs’ or
       ‘processes’.  To turn off verbose display only for jobs:

              zstyle:completion:*:*:kill:*:jobsverbose no

       The -e option to zstyle even allows completion function code to  appear
       as  the  argument  to  a style; this requires some understanding of the
       internals  of  completion  functions  (see  see  zshcompwid(1))).   For
       example,

              zstyle -e:completion:*hostsreply=($myhosts)’

       This  forces  the value of the hosts style to be read from the variable
       myhosts each time a host name is needed; this is useful if the value of
       myhosts  can  change  dynamically.  For another useful example, see the
       example in the description of the file-list style below.  This form can
       be slow and should be avoided for commonly examined styles such as menu
       and list-rows-first.

       Note that the order in which styles are defined does  not  matter;  the
       style  mechanism uses the most specific possible match for a particular
       style to determine the set of  values.   More  precisely,  strings  are
       preferred  over  patterns  (for example, ‘:completion::complete:foo’ is
       more specific than ‘:completion::complete:*’), and longer patterns  are
       preferred over shorter patterns.

       Style  names  like  those  of  tags  are  arbitrary  and  depend on the
       completion function.  However, the following two sections list some  of
       the most common tags and styles.

   Standard Tags
       Some  of  the following are only used when looking up particular styles
       and do not refer to a type of match.

       accounts
              used to look up the users-hosts style

       all-expansions
              used by the _expand completer  when  adding  the  single  string
              containing all possible expansions

       all-files
              for  the  names  of  all  files  (as  distinct from a particular
              subset, see the globbed-files tag).

       arguments
              for arguments to a command

       arrays for names of array parameters

       association-keys
              for keys of associative arrays; used when  completing  inside  a
              subscript to a parameter of this type

       bookmarks
              when  completing  bookmarks (e.g. for URLs and the zftp function
              suite)

       builtins
              for names of builtin commands

       characters
              for single characters in arguments of  commands  such  as  stty.
              Also  used  when  completing  character classes after an opening
              bracket

       colormapids
              for X colormap ids

       colors for color names

       commands
              for names of external commands.  Also used by  complex  commands
              such as cvs when completing names subcommands.

       contexts
              for contexts in arguments to the zstyle builtin command

       corrections
              used  by  the  _approximate and _correct completers for possible
              corrections

       cursors
              for cursor names used by X programs

       default
              used in some contexts to provide a way of  supplying  a  default
              when  more  specific tags are also valid.  Note that this tag is
              used when only the function field of the context name is set

       descriptions
              used when looking up the value of the format style  to  generate
              descriptions for types of matches

       devices
              for names of device special files

       directories
              for names of directories

       directory-stack
              for entries in the directory stack

       displays
              for X display names

       domains
              for network domains

       expansions
              used  by  the _expand completer for individual words (as opposed
              to the complete set of expansions) resulting from the  expansion
              of a word on the command line

       extensions
              for X server extensions

       file-descriptors
              for numbers of open file descriptors

       files  the  generic  file-matching  tag  used  by  functions completing
              filenames

       fonts  for X font names

       fstypes
              for file system types (e.g. for the mount command)

       functions
              names of functions -- normally shell functions, although certain
              commands may understand other kinds of function

       globbed-files
              for  filenames  when  the  name  has  been  generated by pattern
              matching

       groups for names of user groups

       history-words
              for words from the history

       hosts  for hostnames

       indexes
              for array indexes

       jobs   for jobs (as listed by the ‘jobs’ builtin)

       interfaces
              for network interfaces

       keymaps
              for names of zsh keymaps

       keysyms
              for names of X keysyms

       libraries
              for names of system libraries

       limits for system limits

       local-directories
              for names of directories that are subdirectories of the  current
              working  directory  when  completing arguments of cd and related
              builtin commands (compare path-directories)

       manuals
              for names of manual pages

       mailboxes
              for e-mail folders

       maps   for map names (e.g. NIS maps)

       messages
              used to look up the format style for messages

       modifiers
              for names of X modifiers

       modules
              for modules (e.g. zsh modules)

       my-accounts
              used to look up the users-hosts style

       named-directories
              for named directories (you wouldn’t  have  guessed  that,  would
              you?)

       names  for all kinds of names

       newsgroups
              for USENET groups

       nicknames
              for nicknames of NIS maps

       options
              for command options

       original
              used  by  the _approximate, _correct and _expand completers when
              offering the original string as a match

       other-accounts
              used to look up the users-hosts style

       packages
              for packages (e.g. rpm or installed Debian packages)

       parameters
              for names of parameters

       path-directories
              for names of directories found by  searching  the  cdpath  array
              when  completing  arguments  of  cd and related builtin commands
              (compare local-directories)

       paths  used to  look  up  the  values  of  the  expand,  ambiguous  and
              special-dirs styles

       pods   for perl pods (documentation files)

       ports  for communication ports

       prefixes
              for prefixes (like those of a URL)

       printers
              for print queue names

       processes
              for process identifiers

       processes-names
              used  to  look up the command style when generating the names of
              processes for killall

       sequences
              for sequences (e.g. mh sequences)

       sessions
              for sessions in the zftp function suite

       signals
              for signal names

       strings
              for strings (e.g. the replacement strings  for  the  cd  builtin
              command)

       styles for styles used by the zstyle builtin command

       suffixes
              for filename extensions

       tags   for tags (e.g. rpm tags)

       targets
              for makefile targets

       time-zones
              for time zones (e.g. when setting the TZ parameter)

       types  for types of whatever (e.g. address types for the xhost command)

       urls   used to look up the urls and local styles when completing URLs

       users  for usernames

       values for one of a set of values in certain lists

       variant
              used by _pick_variant  to  look  up  the  command  to  run  when
              determining  what  program is installed for a particular command
              name.

       visuals
              for X visuals

       warnings
              used to look up the format style for warnings

       widgets
              for zsh widget names

       windows
              for IDs of X windows

       zsh-options
              for shell options

   Standard Styles
       Note that the values of  several  of  these  styles  represent  boolean
       values.   Any  of  the strings ‘true’, ‘on’, ‘yes’, and ‘1’ can be used
       for the value ‘true’ and any of the strings ‘false’, ‘off’,  ‘no’,  and
       ‘0’  for  the  value  ‘false’.   The  behavior  for  any other value is
       undefined except where explicitly mentioned.  The default value may  be
       either true or false if the style is not set.

       Some   of  these  styles  are  tested  first  for  every  possible  tag
       corresponding to a type of match, and if no style was  found,  for  the
       default   tag.   The  most  notable  styles  of  this  type  are  menu,
       list-colors  and  styles  controlling  completion   listing   such   as
       list-packed  and  last-prompt).   When tested for the default tag, only
       the function field of the context will be set so that a style using the
       default tag will normally be defined along the lines of:

              zstyle:completion:*:defaultmenu ...

       accept-exact
              This is tested for the default tag in addition to the tags valid
              for the current context.  If it is set to ‘true’ and any of  the
              trial  matches  is  the  same as the string on the command line,
              this match will  immediately  be  accepted  (even  if  it  would
              otherwise be considered ambiguous).

              When  completing  pathnames (where the tag used is ‘paths’) this
              style accepts any number of patterns as the value in addition to
              the  boolean  values.   Pathnames matching one of these patterns
              will be accepted immediately even if the command  line  contains
              some more partially typed pathname components and these match no
              file under the directory accepted.

              This style is also used by the _expand completer  to  decide  if
              words  beginning  with  a tilde or parameter expansion should be
              expanded.  For example, if there are parameters foo and  foobar,
              the  string  ‘$foo’ will only be expanded if accept-exact is set
              to ‘true’; otherwise the completion system will  be  allowed  to
              complete  $foo  to  $foobar.  If the style is set to ‘continue’,
              _expand will add the expansion as a  match  and  the  completion
              system will also be allowed to continue.

       add-space
              This style is used by the _expand completer.  If it is true (the
              default), a space will be inserted  after  all  words  resulting
              from  the  expansion, or a slash in the case of directory names.
              If the value is ‘file’, the completer will only add a  space  to
              names  of  existing  files.   Either a boolean true or the value
              ‘file’ may be combined with ‘subst’, in which case the completer
              will  not add a space to words generated from the expansion of a
              substitution of the form ‘$(...)’ or ‘${...}’.

              The _prefix completer uses this style as a simple boolean  value
              to decide if a space should be inserted before the suffix.

       ambiguous
              This  applies  when  completing non-final components of filename
              paths, in other words those with a trailing  slash.   If  it  is
              set,  the  cursor  is  left after the first ambiguous component,
              even if menu completion is in use.  The style is  always  tested
              with the paths tag.

       assign-list
              When completing after an equals sign that is being treated as an
              assignment, the completion system normally  completes  only  one
              filename.   In  some cases the value  may be a list of filenames
              separated by colons, as with PATH and similar parameters.   This
              style  can  be  set  to a list of patterns matching the names of
              such parameters.

              The default is to complete lists  when  the  word  on  the  line
              already contains a colon.

       auto-description
              If  set,  this style’s value will be used as the description for
              options that are not described by the completion functions,  but
              that  have exactly one argument.  The sequence ‘%d’ in the value
              will  be  replaced  by  the  description  for   this   argument.
              Depending  on personal preferences, it may be useful to set this
              style to something like ‘specify: %d’.  Note that this  may  not
              work for some commands.

       avoid-completer
              This  is  used  by  the  _all_matches completer to decide if the
              string consisting of all matches should be  added  to  the  list
              currently  being  generated.   Its  value  is a list of names of
              completers.  If any of these is the name of the  completer  that
              generated the matches in this completion, the string will not be
              added.

              The default value for this style is ‘_expand _old_list  _correct
              _approximate’,  i.e.  it  contains  the  completers  for which a
              string with all matches will almost never be wanted.

       cache-path
              This style defines the path where  any  cache  files  containing
              dumped   completion   data   are   stored.    It   defaults   to
              ‘$ZDOTDIR/.zcompcache’, or ‘$HOME/.zcompcache’  if  $ZDOTDIR  is
              not  defined.   The completion cache will not be used unless the
              use-cache style is set.

       cache-policy
              This style defines the function that will be used  to  determine
              whether  a  cache  needs  rebuilding.   See  the  section on the
              _cache_invalid function below.

       call-command
              This style is used in the function for commands such as make and
              ant  where  calling  the  command  directly  to generate matches
              suffers problems such as being slow or, as in the case  of  make
              can  potentially  causes actions in the makefile to be executed.
              If it is set  to  ‘true’  the  command  is  called  to  generate
              matches. The default value of this style is ‘false’.

       command
              In  many  places,  completion  functions  need  to call external
              commands to generate the list of completions.  This style can be
              used  to override the command that is called in some such cases.
              The elements of the value are  joined  with  spaces  to  form  a
              command  line  to  execute.   The  value  can  also start with a
              hyphen, in which case the usual command will  be  added  to  the
              end;  this  is most useful for putting ‘builtin’ or ‘command’ in
              front to make sure the  appropriate  version  of  a  command  is
              called,  for  example to avoid calling a shell function with the
              same name as an external command.

              As an example, the completion function for process IDs uses this
              style with the processes tag to generate the IDs to complete and
              the list of processes  to  display  (if  the  verbose  style  is
              ‘true’).   The list produced by the command should look like the
              output of the ps command.  The first line is not displayed,  but
              is searched for the string ‘PID’ (or ‘pid’) to find the position
              of the process IDs in the following lines.  If the line does not
              contain  ‘PID’, the first numbers in each of the other lines are
              taken as the process IDs to complete.

              Note that the completion function  generally  has  to  call  the
              specified  command  for  each attempt to generate the completion
              list.  Hence care should be taken to specify only commands  that
              take  a  short  time to run, and in particular to avoid any that
              may never terminate.

       command-path
              This is  a  list  of  directories  to  search  for  commands  to
              complete.   The  default  for  this  style  is  the value of the
              special parameter path.

       commands
              This is used by the function  completing  sub-commands  for  the
              system   initialisation  scripts  (residing  in  /etc/init.d  or
              somewhere not too far away from  that).   Its  values  give  the
              default  commands  to  complete for those commands for which the
              completion function isn’t able to find them  out  automatically.
              The  default  for  this  style  are  the two strings ‘start’ and
              ‘stop’.

       complete
              This is used by the _expand_alias function  when  invoked  as  a
              bindable  command.   If  it  set  to  ‘true’ and the word on the
              command line is not the name of an alias, matching  alias  names
              will be completed.

       completer
              The  strings  given as the value of this style provide the names
              of the completer  functions  to  use.  The  available  completer
              functions  are  described  in  the  section  ‘Control Functions’
              below.

              Each string may be either the name of a completer function or  a
              string  of  the  form  ‘function:name’.   In  the first case the
              completer field of the context will  contain  the  name  of  the
              completer  without  the  leading  underscore  and with all other
              underscores  replaced  by  hyphens.   In  the  second  case  the
              function  is  the name of the completer to call, but the context
              will contain the user-defined name in the completer field of the
              context.   If  the name starts with a hyphen, the string for the
              context will be build from the name of the completer function as
              in the first case with the name appended to it.  For example:

                     zstyle:completion:*completer _complete _complete:-foo

              Here,  completion  will call the _complete completer twice, once
              using ‘complete’ and once using ‘complete-foo’ in the  completer
              field  of  the context.  Normally, using the same completer more
              than once only makes sense when used with  the  ‘functions:name’
              form, because otherwise the context name will be the same in all
              calls to the completer; possible exceptions to this rule are the
              _ignored and _prefix completers.

              The  default  value for this style is ‘_complete _ignored’: only
              completion will be done, first using the ignored-patterns  style
              and the $fignore array and then without ignoring matches.

       condition
              This  style is used by the _list completer function to decide if
              insertion of matches  should  be  delayed  unconditionally.  The
              default is ‘true’.

       disabled
              If  this  is  set  to  ‘true’,  the  _expand_alias completer and
              bindable command will try to expand disabled aliases, too.   The
              default is ‘false’.

       disable-stat
              This  is  used  with an empty tag by the _cvs function to decide
              whether the zsh/stat module should be used to generate names  of
              modified files in the appropriate places (this is its only use).
              If the style is set, completion will use the ls command.

       domains
              A list of names of network domains for completion.  If  this  is
              not   set,   domain   names   will   be   taken  from  the  file
              /etc/resolv.conf.

       expand This  style  is  used  when  completing  strings  consisting  of
              multiple parts, such as path names.

              If one of its values is the string ‘prefix’, the partially typed
              word from the line will be expanded as far as possible  even  if
              trailing parts cannot be completed.

              If  one of its values is the string ‘suffix’, matching names for
              components after the first ambiguous one  will  also  be  added.
              This  means that the resulting string is the longest unambiguous
              string possible.  However, menu completion can be used to  cycle
              through all matches.

       fake   This  style may be set for any completion context.  It specifies
              additional  strings  that  will  always  be  completed  in  that
              context.   The  form  of each string is ‘value:description’; the
              colon and description may be omitted, but any literal colons  in
              value must be quoted with a backslash.  Any description provided
              is shown alongside the value in completion listings.

              It is important to use a sufficiently restrictive  context  when
              specifying  fake  strings.   Note that the styles fake-files and
              fake-parameters  provide  additional  features  when  completing
              files or parameters.

       fake-always
              This  works  identically  to  the  fake  style  except  that the
              ignored-patterns style is not applied  to  it.   This  makes  it
              possible  to override a set of matches completely by setting the
              ignored patterns to ‘*’.

              The  following  shows  a  way  of  supplementing  any  tag  with
              arbitrary data, but having it behave for display purposes like a
              separate tag.  In this  example  we  use  the  features  of  the
              tag-order  style  to  divide  the named-directories tag into two
              when performing completion with the standard completer  complete
              for  arguments  of cd.  The tag named-directories-normal behaves
              as normal, but the tag named-directories-mine contains  a  fixed
              set  of  directories.   This  has the effect of adding the match
              group ‘extra directories’ with the given completions.

                     zstyle:completion::complete:cd:*tag-order \named-directories:-mine:extra\ directories
                       named-directories:-normal:named\ directories *zstyle:completion::complete:cd:*:named-directories-mine\
                       fake-always mydir1 mydir2
                     zstyle:completion::complete:cd:*:named-directories-mine\
                       ignored-patterns*fake-files
              This style is used when completing files and looked up without a
              tag.   Its values are of the form ‘dir:names...’.  This will add
              the names (strings separated by spaces) as possible matches when
              completing  in  the  directory dir, even if no such files really
              exist.

              This can be useful on systems that support  special  filesystems
              whose  top-level  pathnames  can not be listed or generated with
              glob patterns.  It can also be used for  directories  for  which
              one does not have read permission.

       fake-parameters
              This  is  used  by  the completion function for parameter names.
              Its values are names of parameters that might not yet be set but
              should be completed nonetheless.  Each name may also be followed
              by a colon and a string specifying the  type  of  the  parameter
              (like  ‘scalar’,  ‘array’  or ‘integer’).  If the type is given,
              the name will only be completed if parameters of that  type  are
              required  in the particular context.  Names for which no type is
              specified will always be completed.

       file-list
              This style controls whether files completed using  the  standard
              builtin  mechanism  are to be listed with a long list similar to
              ls -l.  Note that this feature uses the  shell  module  zsh/stat
              for  file  information;  this  loads the builtin stat which will
              replace  any  external  stat  executable.   To  avoid  this  the
              following code can be included in an initialization file:

                     zmodload -i zsh/stat
                     disable stat

              The  style  may either be set to a true value (or ‘all’), or one
              of the values ‘insert’ or ‘list’, indicating that files  are  to
              be   listed  in  long  format  in  all  circumstances,  or  when
              attempting to insert a file name, or  when  listing  file  names
              without attempting to insert one.

              More  generally,  the  value may be an array of any of the above
              values, optionally followed by =num.  If num is present it gives
              the  maximum number of matches for which long listing style will
              be used.  For example,

                     zstyle:completion:*file-list list=20 insert=10

              specifies that long format will be used when listing  up  to  20
              files  or  inserting  a  file  with up to 10 matches (assuming a
              listing is to be shown at  all,  for  example  on  an  ambiguous
              completion), else short format will be used.

                     zstyle -e:completion:*file-list(( ${+NUMERIC} )) && reply=(true)’

              specifies  that  long  format  will  be  used any time a numeric
              argument is supplied, else short format.

       file-patterns
              This is used by the standard function for completing  filenames,
              _files.   If  the  style  is unset up to three tags are offered,
              ‘globbed-files’,‘directories’ and ‘all-files’, depending on  the
              types of files  expected by the caller of _files.  The first two
              (‘globbed-files’  and  ‘directories’)   are   normally   offered
              together to make it easier to complete files in sub-directories.

              The file-patterns style provides  alternatives  to  the  default
              tags, which are not used.  Its value consists of elements of the
              form ‘pattern:tag’; each string may contain any number  of  such
              specifications separated by spaces.

              The  pattern  is  a  pattern  that  is  to  be  used to generate
              filenames.  Any occurrence of the sequence ‘%p’ is  replaced  by
              any pattern(s) passed by the function calling _files.  Colons in
              the pattern must  be  preceded  by  a  backslash  to  make  them
              distinguishable from the colon before the tag.  If more than one
              pattern is needed, the patterns  can  be  given  inside  braces,
              separated by commas.

              The  tags  of all strings in the value will be offered by _files
              and used when looking up other styles.  Any  tags  in  the  same
              word  will  be  offered at the same time and before later words.
              If no ‘:tag’ is given the ‘files’ tag will be used.

              The tag may also be followed by an optional second colon  and  a
              description, which will be used for the ‘%d’ in the value of the
              format style (if that is set) instead of the default description
              supplied  by  the completion function.  If the description given
              here  contains  itself  a  ‘%d’,  that  is  replaced  with   the
              description supplied by the completion function.

              For example, to make the rm command first complete only names of
              object files and then the names of all  files  if  there  is  no
              matching object file:

                     zstyle:completion:*:*:rm:*file-patterns \*.o:object-files’ ’%p:all-files’

              To alter the default behaviour of file completion -- offer files
              matching a pattern and directories on the  first  attempt,  then
              all  files -- to offer only matching files on the first attempt,
              then directories, and finally all files:

                     zstyle:completion:*file-patterns \%p:globbed-files’ ’*(-/):directories’ ’*:all-files’

              This works even  where  there  is  no  special  pattern:  _files
              matches  all  files  using the pattern ‘*’ at the first step and
              stops when it sees this pattern.  Note also it will never try  a
              pattern more than once for a single completion attempt.

              During  the execution of completion functions, the EXTENDED_GLOB
              option is in effect, so the characters ‘#’,  ‘~’  and  ‘^’  have
              special meanings in the patterns.

       file-sort
              The  standard  filename  completion  function  uses  this  style
              without a tag to determine in which order the  names  should  be
              listed;  menu  completion  will  cycle  through them in the same
              order.  The possible values are: ‘size’ to sort by the  size  of
              the  file;  ‘links’  to sort by the number of links to the file;
              ‘modification’ (or  ‘time’  or  ‘date’)  to  sort  by  the  last
              modification time; ‘access’ to sort by the last access time; and
              ‘inode’ (or ‘change’) to sort by the last inode change time.  If
              the  style is set to any other value, or is unset, files will be
              sorted alphabetically by name.  If the value contains the string
              ‘reverse’, sorting is done in the opposite order.

       filter This is used by the LDAP plugin for e-mail address completion to
              specify the attributes to match against when filtering  entries.
              So  for  example,  if the style is set to ‘sn’, matching is done
              against surnames.  Standard LDAP filtering  is  used  so  normal
              completion  matching is bypassed.  If this style is not set, the
              LDAP plugin is skipped.  You may also need to  set  the  command
              style to specify how to connect to your LDAP server.

       force-list
              This forces a list of completions to be shown at any point where
              listing is done, even in cases where the list would  usually  be
              suppressed.   For  example,  normally  the list is only shown if
              there are at least two different matches.  By setting this style
              to  ‘always’,  the  list  will always be shown, even if there is
              only a single match that  will  immediately  be  accepted.   The
              style  may  also be set to a number.  In this case the list will
              be shown if there are at least that many matches, even  if  they
              would all insert the same string.

              This style is tested for the default tag as well as for each tag
              valid for the current completion.   Hence  the  listing  can  be
              forced only for certain types of match.

       format If  this is set for the descriptions tag, its value is used as a
              string to  display  above  matches  in  completion  lists.   The
              sequence  ‘%d’  in  this  string  will  be replaced with a short
              description of what these matches are.   This  string  may  also
              contain  the  sequences  to  specify  output attributes, such as
              ‘%B’, ‘%S’ and ‘%{...%}’.

              The style  is  tested  with  each  tag  valid  for  the  current
              completion  before it is tested for the descriptions tag.  Hence
              different format strings can be defined for different  types  of
              match.

              Note  also  that  some  completer  functions  define  additional
              ‘%’-sequences.  These are described for the completer  functions
              that make use of them.

              Some   completion   functions   display  messages  that  may  be
              customised by setting this style for the  messages  tag.   Here,
              the  ‘%d’  is  replaced  with  a message given by the completion
              function.

              Finally, the format string is looked up with the  warnings  tag,
              for use when no matches could be generated at all.  In this case
              the ‘%d’ is replaced with the descriptions for the matches  that
              were  expected  separated  by  spaces.   The  sequence  ‘%D’  is
              replaced with the same descriptions separated by newlines.

              It is possible to use printf-style field width  specifiers  with
              ‘%d’  and  similar  escape  sequences.   This  is handled by the
              zformat  builtin  command  from  the   zsh/zutil   module,   see
              zshmodules(1).

       glob   This  is  used by the _expand completer.  If it is set to ‘true’
              (the default), globbing will be attempted on the words resulting
              from  a previous substitution (see the substitute style) or else
              the original string from the line.

       global If this is  set  to  ‘true’  (the  default),  the  _expand_alias
              completer  and  bindable  command  will  try  to  expand  global
              aliases.

       group-name
              The completion system can  group  different  types  of  matches,
              which  appear in separate lists.  This style can be used to give
              the names of  groups  for  particular  tags.   For  example,  in
              command  position  the  completion  system  generates  names  of
              builtin and external commands, names of aliases, shell functions
              and  parameters  and reserved words as possible completions.  To
              have  the  external  commands   and   shell   functions   listed
              separately:

                     zstyle:completion:*:*:-command-:*:commandsgroup-name commands
                     zstyle:completion:*:*:-command-:*:functionsgroup-name functions

              As  a consequence, any match with the same tag will be displayed
              in the same group.

              If the name given is the empty string the name of  the  tag  for
              the  matches will be used as the name of the group.  So, to have
              all different types of matches  displayed  separately,  one  can
              just set:

                     zstyle:completion:*group-name ’’

              All  matches for which no group name is defined will be put in a
              group named -default-.

       group-order
              This style is additional to the group-name style to specify  the
              order  for  display of the groups defined by that style (compare
              tag-order, which determines which completions  appear  at  all).
              The  groups named are shown in the given order; any other groups
              are shown in the order defined by the completion function.

              For example, to have names of builtin commands, shell  functions
              and  external  commands  appear in that order when completing in
              command position:

                     zstyle:completion:*:*:-command-:*group-order \
                            builtins functions commands

       groups A list of names of UNIX groups.  If this is not set, group names
              are taken from the YP database or the file ‘/etc/group’.

       hidden If  this  is set to true, matches for the given context will not
              be listed, although any description for the matches set with the
              format style will be shown.  If it is set to ‘all’, not even the
              description will be displayed.

              Note that the matches will still be completed; they are just not
              shown  in  the  list.   To  avoid  having  matches considered as
              possible completions at all, the tag-order style can be modified
              as described below.

       hosts  A  list  of names of hosts that should be completed.  If this is
              not set, hostnames are taken from the file ‘/etc/hosts’.

       hosts-ports
              This style is used by commands that need or accept hostnames and
              network  ports.   The strings in the value should be of the form
              ‘host:port’.  Valid ports are  determined  by  the  presence  of
              hostnames; multiple ports for the same host may appear.

       ignore-line
              This  is  tested  for each tag valid for the current completion.
              If it is set to ‘true’, none of the words that  are  already  on
              the  line  will be considered as possible completions.  If it is
              set to ‘current’,  the  word  the  cursor  is  on  will  not  be
              considered  as a possible completion.  The value ‘current-shown’
              is similar but only  applies  if  the  list  of  completions  is
              currently  shown on the screen.  Finally, if the style is set to
              ‘other’, no word apart from the current one will  be  considered
              as a possible completion.

              The  values  ‘current’  and  ‘current-shown’  are a bit like the
              opposite of the accept-exact style:  only strings  with  missing
              characters will be completed.

              Note  that you almost certainly don’t want to set this to ‘true’
              or ‘other’ for a general context such as ‘:completion:*’.   This
              is because it would disallow completion of, for example, options
              multiple times even if  the  command  in  question  accepts  the
              option more than once.

       ignore-parents
              The  style  is  tested  without a tag by the function completing
              pathnames in order to determine whether to ignore the  names  of
              directories  already  mentioned in the current word, or the name
              of the current working directory.  The value must include one or
              both of the following strings:

              parent The name of any directory whose path is already contained
                     in the word on the line is ignored.   For  example,  when
                     completing  after  foo/../, the directory foo will not be
                     considered a valid completion.

              pwd    The name of the current working  directory  will  not  be
                     completed;  hence, for example, completion after ../ will
                     not use the name of the current directory.

              In addition, the value may include one or both of:

              ..     Ignore the specified directories only when  the  word  on
                     the line contains the substring ‘../’.

              directory
                     Ignore  the  specified  directories  only  when  names of
                     directories are completed, not when completing  names  of
                     files.

              Excluded  values  act  in  a  similar  fashion  to values of the
              ignored-patterns style, so they can be restored to consideration
              by the _ignored completer.

       ignored-patterns
              A  list  of  patterns;  any trial completion matching one of the
              patterns will be  excluded  from  consideration.   The  _ignored
              completer  can  appear  in the list of completers to restore the
              ignored matches.  This is a more  configurable  version  of  the
              shell parameter $fignore.

              Note  that  the EXTENDED_GLOB option is set during the execution
              of completion functions, so the characters ‘#’, ‘~’ and ‘^’ have
              special meanings in the patterns.

       insert This  style  is  used  by  the  _all_matches completer to decide
              whether to  insert  the  list  of  all  matches  unconditionally
              instead of adding the list as another match.

       insert-ids
              When  completing  process  IDs,  for example as arguments to the
              kill and wait builtins the name of a command may be converted to
              the  appropriate  process ID.  A problem arises when the process
              name typed is not unique.  By default (or if this style  is  set
              explicitly  to ‘menu’) the name will be converted immediately to
              a set of possible IDs, and menu completion will  be  started  to
              cycle through them.

              If the value of the style is ‘single’, the shell will wait until
              the user has typed enough to  make  the  command  unique  before
              converting  the  name  to  an ID; attempts at completion will be
              unsuccessful until that  point.   If  the  value  is  any  other
              string, menu completion will be started when the string typed by
              the user is longer than the common prefix to  the  corresponding
              IDs.

       insert-tab
              If  this  is  set to ‘true’, the completion system will insert a
              TAB character (assuming  that  was  used  to  start  completion)
              instead  of  performing  completion  when  there is no non-blank
              character to the left of the cursor.  If it is set  to  ‘false’,
              completion will be done even there.

              The   value   may  also  contain  the  substrings  ‘pending’  or
              ‘pending=val’.  In  this  case,  the  typed  character  will  be
              inserted instead of staring completion when there is unprocessed
              input pending.  If a val is given, completion will not  be  done
              if there are at least that many characters of unprocessed input.
              This is often useful when pasting characters  into  a  terminal.
              Note  however,  that it relies on the $PENDING special parameter
              from  the  zsh/zle  module  being  set  properly  which  is  not
              guaranteed on all platforms.

              The  default value of this style is ‘true’ except for completion
              within vared builtin command where it is ‘false’.

       insert-unambiguous
              This is used by the _match and _approximate  completers.   These
              completers  are  often  used with menu completion since the word
              typed may bear  little  resemblance  to  the  final  completion.
              However,  if this style is ‘true’, the completer will start menu
              completion only if it could find no unambiguous  initial  string
              at least as long as the original string typed by the user.

              In  the  case of the _approximate completer, the completer field
              in the context will already have been set to one of  correct-num
              or  approximate-num, where num is the number of errors that were
              accepted.

              In the case of the _match completer, the style may also  be  set
              to  the  string ‘pattern’.  Then the pattern on the line is left
              unchanged if it does not match unambiguously.

       keep-prefix
              This style is used by the _expand completer.  If it  is  ‘true’,
              the  completer  will  try to keep a prefix containing a tilde or
              parameter expansion.  Hence,  for  example,  the  string  ‘~/f*’
              would  be  expanded  to ‘~/foo’ instead of ‘/home/user/foo’.  If
              the style is set to ‘changed’ (the  default),  the  prefix  will
              only  be  left unchanged if there were other changes between the
              expanded words and the original word from the command line.  Any
              other value forces the prefix to be expanded unconditionally.

              The  behaviour  of  expand  when  this style is true is to cause
              _expand to give up when a single  expansion  with  the  restored
              prefix  is  the  same  as  the  original;  hence  any  remaining
              completers may be called.

       last-prompt
              This is a more flexible form of the  ALWAYS_LAST_PROMPT  option.
              If  it  is  true,  the  completion system will try to return the
              cursor  to  the  previous  command  line  after   displaying   a
              completion  list.   It  is  tested  for  all  tags valid for the
              current completion, then the default tag.  The  cursor  will  be
              moved  back to the previous line if this style is ‘true’ for all
              types of match.  Note that unlike the ALWAYS_LAST_PROMPT  option
              this is independent of the numeric prefix argument.

       known-hosts-files
              This  style  should  contain  a list of files to search for host
              names and (if the use-ip style is set) IP addresses in a  format
              compatible  with  ssh  known_hosts files.  If it is not set, the
              files /etc/ssh/ssh_known_hosts and ~/.ssh/known_hosts are  used.

       list   This  style  is  used  by  the  _history_complete_word  bindable
              command.  If it is set to ‘true’ it has no effect.  If it is set
              to  ‘false’  matches  will  not  be  listed.  This overrides the
              setting  of  the  options  controlling  listing  behaviour,   in
              particular   AUTO_LIST.    The   context   always   starts  with
              ‘:completion:history-words’.

       list-colors
              If the zsh/complist module is loaded, this style can be used  to
              set  color  specifications.   This mechanism replaces the use of
              the ZLS_COLORS  and  ZLS_COLOURS  parameters  described  in  the
              section  ‘The  zsh/complist  Module’  in  zshmodules(1), but the
              syntax is the same.

              If this style is set for the default tag,  the  strings  in  the
              value   are   taken  as  specifications  that  are  to  be  used
              everywhere.  If it is set for other tags, the specifications are
              used  only  for  matches  of the type described by the tag.  For
              this to work best, the group-name style must be set to an  empty
              string.

              In  addition  to  setting  styles  for specific tags, it is also
              possible  to  use  group  names  specified  explicitly  by   the
              group-name tag together with the ‘(group)’ syntax allowed by the
              ZLS_COLORS and  ZLS_COLOURS  parameters  and  simply  using  the
              default tag.

              It  is  possible  to use any color specifications already set up
              for the GNU version of the ls command:

                     zstyle:completion:*:defaultlist-colors ${(s.:.)LS_COLORS}

              The default colors are the same as for the GNU  ls  command  and
              can  be  obtained  by setting the style to an empty string (i.e.
              ’’).

       list-grouped
              If this style is ‘true’ (the  default),  the  completion  system
              will  try  to  make  certain completion listings more compact by
              grouping matches.  For example, options for commands  that  have
              the  same  description  (shown  when the verbose style is set to
              ‘true’) will appear as a single entry.  However, menu  selection
              can be used to cycle through all the matches.

       list-packed
              This is tested for each tag valid in the current context as well
              as the default tag.  If it is set to ‘true’,  the  corresponding
              matches  appear  in  listings  as if the LIST_PACKED option were
              set.  If it is set to ‘false’, they are listed normally.

       list-prompt
              If this style is set for the default tag, completion lists  that
              don’t  fit on the screen can be scrolled (see the description of
              the zsh/complist module in zshmodules(1)).  The  value,  if  not
              the  empty  string,  will be displayed after every screenful and
              the shell will prompt for a key press; if the style  is  set  to
              the empty string, a default prompt will be used.

              The  value may contain the escape sequences: ‘%l’ or ‘%L’, which
              will be replaced by the number of the last  line  displayed  and
              the total number of lines; ‘%m’ or ‘%M’, the number of the  last
              match shown and the total number of matches; and ‘%p’ and  ‘%P’,
              ‘Top’  when  at  the beginning of the list, ‘Bottom’ when at the
              end and the position shown as a percentage of the  total  length
              otherwise.  In each case the form with the uppercase letter will
              be replaced by a string of fixed width,  padded  to  the   right
              with  spaces,  while  the  lowercase  form will be replaced by a
              variable width string.  As in other prompt strings,  the  escape
              sequences  ‘%S’,  ‘%s’,  ‘%B’, ‘%b’, ‘%U’, ‘%u’ for entering and
              leaving the display modes standout, bold and underline are  also
              available,  as  is  the  form  ‘%{...%}’  for  enclosing  escape
              sequences which display with zero width.

              After deleting this prompt the  variable  LISTPROMPT  should  be
              unset for the the removal to take effect.

       list-rows-first
              This  style  is  tested in the same way as the list-packed style
              and determines whether matches are to be listed in a  rows-first
              fashion as if the LIST_ROWS_FIRST option were set.

       list-suffixes
              This style is used by the function that completes filenames.  If
              it is true, and completion is attempted on a  string  containing
              multiple  partially  typed  pathname  components,  all ambiguous
              components will be shown.  Otherwise, completion  stops  at  the
              first ambiguous component.

       list-separator
              The  value  of  this  style  is  used  in  completion listing to
              separate the string to complete from a description when possible
              (e.g.  when  completing  options).   It  defaults  to  ‘--’ (two
              hyphens).

       local  This is for use with functions that complete URLs for which  the
              corresponding  files  are  available  directly  from  the filing
              system.  Its value should consist of three strings: a  hostname,
              the  path  to  the  default  web  pages  for the server, and the
              directory name used by a user placing  web  pages  within  their
              home area.

              For example:

                     zstyle:completion:*local toast \
                         /var/http/public/toast public_html

              Completion  after  ‘http://toast/stuff/’  will look for files in
              the directory  /var/http/public/toast/stuff,   while  completion
              after   ‘http://toast/~yousir/’  will  look  for  files  in  the
              directory ~yousir/public_html.

       mail-directory
              If set, zsh will assume that mailbox files can be found  in  the
              directory specified.  It defaults to ‘~/Mail’.

       match-original
              This  is  used  by  the _match completer.  If it is set to only,
              _match will try to generate matches without inserting a  ‘*’  at
              the  cursor  position.   If set to any other non-empty value, it
              will first try to generate matches without inserting the ‘*’ and
              if  that  yields  no  matches,  it  will  try again with the ‘*’
              inserted.  If it is unset or set to the empty  string,  matching
              will only be performed with the ‘*’ inserted.

       matcher
              This  style  is  tested  separately  for  each  tag valid in the
              current context.  Its value is added to any match specifications
              given  by  the  matcher-list  style.   It  should be in the form
              described in the section ‘Matching Control’ in zshcompwid(1).

       matcher-list
              This style can be set to a list of match specifications that are
              to  be applied everywhere. Match specifications are described in
              the section ‘Matching Control’ in zshcompwid(1).  The completion
              system  will  try  them  one  after  another  for each completer
              selected.  For example, to try first simple completion  and,  if
              that generates no matches, case-insensitive completion:

                     zstyle:completion:*matcher-list ’’ ’m:{a-zA-Z}={A-Za-z}’

              By   default  each  specification  replaces  the  previous  one;
              however, if a specification is prefixed with +, it is  added  to
              the  existing list.  Hence it is possible to create increasingly
              general specifications without repetition:

                     zstyle:completion:*matcher-list ’’ ’+m{a-Z}={A-Z}’ ’+m{A-Z}={a-z}’

              It  is  possible  to  create  match  specifications  valid   for
              particular  completers  by using the third field of the context.
              For example, to use the completers  _complete  and  _prefix  but
              only allow case-insensitive completion with _complete:

                     zstyle:completion:*completer _complete _prefix
                     zstyle:completion:*:complete:*matcher-list \
                            ’’ ’m:{a-zA-Z}={A-Za-z}’

              User-defined  names,  as  explained for the completer style, are
              available.  This makes it possible to  try  the  same  completer
              more  than  once  with different match specifications each time.
              For  example,  to  try  normal  completion   without   a   match
              specification,  then  normal  completion  with  case-insensitive
              matching, then correction, and finally partial-word completion:

                     zstyle:completion:*completer _complete _correct _complete:foo
                     zstyle:completion:*:complete:*matcher-list \
                         ’’ ’m:{a-zA-Z}={A-Za-z}zstyle:completion:*:foo:*matcher-list \m:{a-zA-Z}={A-Za-z} r:|[-_./]=* r:|=*’

              If the style is unset in any context no match  specification  is
              applied.   Note  also  that some completers such as _correct and
              _approximate do not use the match specifications at all,  though
              these  completers  will  only  ever  called  once  even  if  the
              matcher-list contains more than one element.

              Where multiple specifications are useful, note that  the  entire
              completion  is  done for each element of matcher-list, which can
              quickly reduce the shell’s performance.   As  a  rough  rule  of
              thumb,  one  to  three strings will give acceptable performance.
              On the other hand, putting multiple space-separated values  into
              the   same  string  does  not  have  an  appreciable  impact  on
              performance.

       max-errors
              This  is  used  by  the  _approximate  and  _correct   completer
              functions  to  determine  the maximum number of errors to allow.
              The completer will try to generate completions by first allowing
              one  error,  then two errors, and so on, until either a match or
              matches were found or the maximum number of errors given by this
              style has been reached.

              If  the  value for this style contains the string ‘numeric’, the
              completer function will take any numeric argument as the maximum
              number of errors allowed. For example, with

                     zstyle:completion:*:approximate:::max-errors 2 numeric

              two errors are allowed if no numeric argument is given, but with
              a numeric argument of six (as in ‘ESC-6 TAB’), up to six  errors
              are  accepted.  Hence with a value of ‘0 numeric’, no correcting
              completion will be attempted unless a numeric argument is given.

              If  the  value  contains the string ‘not-numeric’, the completer
              will not try to generate  corrected  completions  when  given  a
              numeric  argument,  so  in  this case the number given should be
              greater than zero.  For example, ‘2 not-numeric’ specifies  that
              correcting completion with two errors will usually be performed,
              but if a numeric argument is given, correcting  completion  will
              not be performed.

              The default value for this style is ‘2 numeric’.

       max-matches-width
              This  style is used to determine the trade off between the width
              of the display used for matches and the  width  used  for  their
              descriptions  when  the  verbose  style is in effect.  The value
              gives the number of display columns to reserve for the  matches.
              The default is half the width of the screen.

              This  has  the  most  impact  when several matches have the same
              description and so will be  grouped  together.   Increasing  the
              style will allow more matches to be grouped together; decreasing
              it will allow more of the description to be visible.

       menu   If this is true in the context of any of the  tags  defined  for
              the  current completion menu completion will be used.  The value
              for a specific tag  will  take  precedence  over  that  for  the
              ‘default’ tag.

              If none of the values found in this way is true but at least one
              is set to ‘auto’, the shell behaves as if the  AUTO_MENU  option
              is set.

              If one of the values is explicitly set to false, menu completion
              will be explicitly  turned  off,  overriding  the  MENU_COMPLETE
              option and other settings.

              In the form ‘yes=num’, where ‘yes’ may be any of the true values
              (‘yes’, ‘true’, ‘on’ and ‘1’), menu completion will be turned on
              if there are at least num matches.  In the form ‘yes=long’, menu
              completion will be turned on if the list does  not  fit  on  the
              screen.   This  does  not activate menu completion if the widget
              normally only lists completions,  but  menu  completion  can  be
              activated   in   that   case   with  the  value  ‘yes=long-list’
              (Typically, the value ‘select=long-list’ described later is more
              useful as it provides control over scrolling.)

              Similarly,  with any of the ‘false’ values (as in ‘no=10’), menu
              completion will not be used if there are num or more matches.

              The value of  this  widget  also  controls  menu  selection,  as
              implemented  by  the  zsh/complist module.  The following values
              may appear either alongside or instead of the values above.

              If the value contains the string ‘select’, menu  selection  will
              be started unconditionally.

              In the form ‘select=num’, menu selection will only be started if
              there are at least num matches.  If the values for more than one
              tag provide a number, the smallest number is taken.

              Menu  selection can be turned off explicitly by defining a value
              containing the string‘no-select’.

              It is also possible to start menu selection only if the list  of
              matches   does  not  fit  on  the  screen  by  using  the  value
              ‘select=long’.  To start menu  selection  even  if  the  current
              widget  only performs listing, use the value ‘select=long-list’.

              To turn on menu completion or menu selection when a there are  a
              certain number of matches or the list of matches does not fit on
              the screen, both of ‘yes=’ and ‘select=’  may  be  given  twice,
              once with a number and once with ‘long’ or ‘long-list’.

              Finally,  it  is  possible to activate two special modes of menu
              selection.   The  word  ‘interactive’  in   the   value   causes
              interactive  mode  to be entered immediately when menu selection
              is started; see the description of the  zsh/complist  module  in
              zshmodules(1).RE   for   a   description  of  interactive  mode.
              Including the string ‘search’  does  the  same  for  incremental
              search mode.  To select backward incremental search, include the
              string ‘search-backward’.  )

              muttrc If set, gives the  location  of  the  mutt  configuration
                     file.  It defaults to ‘~/.muttrc’.

              numbers
                     This  is  used  with  the jobs tag.  If it is ‘true’, the
                     shell will complete job numbers instead of  the  shortest
                     unambiguous prefix of the job command text.  If the value
                     is a number, job numbers will only be used if  that  many
                     words  from  the job descriptions are required to resolve
                     ambiguities.  For example, if the value is  ‘1’,  strings
                     will only be used if all jobs differ in the first word on
                     their command lines.

              old-list
                     This is used by the _oldlist completer.  If it is set  to
                     ‘always’,  then  standard  widgets  which perform listing
                     will retain the current list  of  matches,  however  they
                     were  generated;  this  can be turned off explicitly with
                     the value  ‘never’,  giving  the  behaviour  without  the
                     _oldlist  completer.  If the style is unset, or any other
                     value, then the existing list of completions is displayed
                     if  it is not already; otherwise, the standard completion
                     list is generated;  this  is  the  default  behaviour  of
                     _oldlist.   However,  if  there  is  an old list and this
                     style contains the name of the  completer  function  that
                     generated  the  list, then the old list will be used even
                     if it was  generated  by  a  widget  which  does  not  do
                     listing.

                     For   example,   suppose   you   type   ^Xc  to  use  the
                     _correct_word  widget,  which   generates   a   list   of
                     corrections  for  the  word  under  the cursor.  Usually,
                     typing ^D would generate a standard list  of  completions
                     for  the  word  on the command line, and show that.  With
                     _oldlist, it will instead show the  list  of  corrections
                     already generated.

                     As  another  example  consider the _match completer: with
                     the insert-unambiguous style set  to  ‘true’  it  inserts
                     only  a  common prefix string, if there is any.  However,
                     this may remove parts of the original  pattern,  so  that
                     further completion could produce more matches than on the
                     first attempt.   By  using  the  _oldlist  completer  and
                     setting  this  style  to  _match,  the  list  of  matches
                     generated on the first attempt will be used again.

              old-matches
                     This is used by the _all_matches completer to  decide  if
                     an  old  list  of  matches  should be used if one exists.
                     This is selected by one of the ‘true’ values  or  by  the
                     string ‘only’.  If the value is ‘only’, _all_matches will
                     only use an old list and won’t have  any  effect  on  the
                     list of matches currently being generated.

                     If  this  style is set it is generally unwise to call the
                     _all_matches completer unconditionally.  One possible use
                     is  for  either  this  style or the completer style to be
                     defined with the -e option to zstyle to  make  the  style
                     conditional.

              old-menu
                     This  is used by the _oldlist completer.  It controls how
                     menu completion behaves when  a  completion  has  already
                     been  inserted  and  the user types a standard completion
                     key such as TAB.  The default behaviour  of  _oldlist  is
                     that  menu  completion always continues with the existing
                     list of completions.  If this style is  set  to  ‘false’,
                     however,  a new completion is started if the old list was
                     generated by a different completion command; this is  the
                     behaviour without the _oldlist completer.

                     For  example,  suppose you type ^Xc to generate a list of
                     corrections, and menu completion is started in one of the
                     usual  ways.   Usually,  or with this style set to false,
                     typing TAB at this point would start trying  to  complete
                     the  line  as  it now appears.  With _oldlist, it instead
                     continues to cycle through the list of corrections.

              original
                     This is used by the _approximate and _correct  completers
                     to  decide  if  the  original string should be added as a
                     possible completion.  Normally,  this  is  done  only  if
                     there  are at least two possible corrections, but if this
                     style is set to ‘true’, it is always  added.   Note  that
                     the  style  will  be examined with the completer field in
                     the context name set to correct-num  or  approximate-num,
                     where num is the number of errors that were accepted.

              packageset
                     This  style  is  used  when  completing  arguments of the
                     Debian ‘dpkg’ program.  It contains an override  for  the
                     default package set for a given context.  For example,

                             zstyle:completion:*:complete:dpkg:option--status-1:*\
                                            packageset avail

                     causes  available  packages,  rather  than only installed
                     packages, to be completed for ‘dpkg --status’.

              path   The function that completes color names uses  this  style
                     with the colors tag.  The value should be the pathname of
                     a file containing color names in the  format  of  an  X11
                     rgb.txt  file.   If the style is not set but this file is
                     found in one of various standard  locations  it  will  be
                     used as the default.

              pine-directory
                     If  set,  specifies the directory containing PINE mailbox
                     files.  There is no default, since recursively  searching
                     this directory is inconvenient for anyone who doesn’t use
                     PINE.

              ports  A list of  Internet  service  names  (network  ports)  to
                     complete.   If  this  is not set, service names are taken
                     from the file ‘/etc/services’.

              prefix-hidden
                     This is used for certain completions which share a common
                     prefix,   for  example  command  options  beginning  with
                     dashes.  If it is ‘true’, the prefix will not be shown in
                     the list of matches.

                     The default value for this style is ‘false’.

              prefix-needed
                     This,  too, is used for matches with a common prefix.  If
                     it is set to ‘true’ this common prefix must be  typed  by
                     the user to generate the matches.  In the case of command
                     options, this means that the initial ‘-’,  ‘+’,  or  ‘--’
                     must  be  typed  explicitly  before  option names will be
                     completed.

                     The default value for this style is ‘true’.

              preserve-prefix
                     This style is used when completing path names.  Its value
                     should  be  a  pattern  matching an initial prefix of the
                     word to complete that should be left unchanged under  all
                     circumstances.   For  example,  on some Unices an initial
                     ‘//’ (double slash) has a special meaning;  setting  this
                     style  to  the  string ‘//’ will preserve it.  As another
                     example, setting this style to ‘?:/’ under  Cygwin  would
                     allow completion after ‘a:/...’ and so on.

              range  This   is   used   by  the  _history  completer  and  the
                     _history_complete_word bindable command to  decide  which
                     words should be completed.

                     If  it  is a singe number, only the last N words from the
                     history will be completed.

                     If it is a range of the form ‘max:slice’, the last  slice
                     words  will be completed; then if that yields no matches,
                     the slice words before those will be  tried  and  so  on.
                     This  process  stops  either  when at least one match was
                     been found, or max words have been tried.

                     The default is to complete all words from the history  at
                     once.

              regular
                     This  style  is  used  by the _expand_alias completer and
                     bindable  command.   If  set  to  ‘true’  (the  default),
                     regular  aliases  will  be  expanded  but only in command
                     position.  If it is set to ‘false’, regular aliases  will
                     never  be  expanded.    If it is set to ‘always’, regular
                     aliases will be expanded even if not in command position.

              rehash If  this  is  set  when completing external commands, the
                     internal list (hash) of commands will be updated for each
                     search  by  issuing the rehash command.  There is a speed
                     penalty for this which is only likely  to  be  noticeable
                     when directories in the path have slow file access.

              remote-access
                     If  set to false, certain commands will be prevented from
                     making   Internet   connections   to   retrieve    remote
                     information.   This  includes  the completion for the CVS
                     command.

                     It is not always possible to know if connections  are  in
                     fact   to  a  remote  site,  so  some  may  be  prevented
                     unnecessarily.

              remove-all-dups
                     The  _history_complete_word  bindable  command  and   the
                     _history  completer  use  this to decide if all duplicate
                     matches should be removed, rather than  just  consecutive
                     duplicates.

              select-prompt
                     If  this  is  set  for the default tag, its value will be
                     displayed during  menu  selection  (see  the  menu  style
                     above)  when  the  completion  list  does  not fit on the
                     screen  as  a  whole.   The  same  escapes  as  for   the
                     list-prompt style are understood, except that the numbers
                     refer to the match or line the mark  is  on.   A  default
                     prompt is used when the value is the empty string.

              select-scroll
                     This  style  is tested for the default tag and determines
                     how a completion list is scrolled during a menu selection
                     (see  the menu style above) when the completion list does
                     not fit on the screen as a whole.  If the  value  is  ‘0’
                     (zero), the list is scrolled by half-screenfuls; if it is
                     a positive integer, the list is  scrolled  by  the  given
                     number  of lines; if it is a negative number, the list is
                     scrolled by a screenful minus the absolute value  of  the
                     given  number  of  lines.   The  default  is to scroll by
                     single lines.

              separate-sections
                     This style is used with the manuals tag  when  completing
                     names  of  manual  pages.   If  it is ‘true’, entries for
                     different sections are added separately using  tag  names
                     of  the  form  ‘manual.X’, where X is the section number.
                     When the group-name style is also in effect,  pages  from
                     different sections will appear separately.  This style is
                     also used similarly with the words style when  completing
                     words   for  the  dict  command.  It  allows  words  from
                     different dictionary databases to  be  added  separately.
                     The default for this style is ‘false’.

              show-completer
                     Tested whenever a new completer is tried.  If it is true,
                     the completion system outputs a progress message  in  the
                     listing  area showing what completer is being tried.  The
                     message  will  be  overwritten   by   any   output   when
                     completions  are found and is removed after completion is
                     finished.

              single-ignored
                     This is used by the _ignored completer when there is only
                     one match.  If its value is ‘show’, the single match will
                     be displayed but not inserted.  If the value  is  ‘menu’,
                     then  the  single  match and the original string are both
                     added as matches and menu completion is  started,  making
                     it easy to select either of them.

              sort   Many  completion  widgets call _description at some point
                     which decides whether the matches  are  added  sorted  or
                     unsorted  (often  indirectly  via _wanted or _requested).
                     This style can be set explicitly to one of the usual true
                     or false values as an override.  If it is not set for the
                     context, the standard behaviour of the calling widget  is
                     used.

                     The  style  is  tested  first  against  the  full context
                     including the tag, and if that fails to produce  a  value
                     against the context without the tag.

                     If   the  calling  widget  explicitly  requests  unsorted
                     matches, this is usually honoured.  However, the  default
                     (unsorted)   behaviour  of  completion  for  the  command
                     history may be overridden by setting the style to true.

                     In the _expand completer, if it is  set  to  ‘true’,  the
                     expansions generated will always be sorted.  If it is set
                     to ‘menu’, then the expansions are only sorted when  they
                     are  offered  as  single  strings  but  not in the string
                     containing all possible expansions.

              special-dirs
                     Normally,  the  completion  code  will  not  produce  the
                     directory names ‘.’ and ‘..’ as possible completions.  If
                     this style is set to ‘true’, it will  add  both  ‘.’  and
                     ‘..’  as possible completions; if it is set to ‘..’, only
                     ‘..’ will be added.

                     The following example sets special-dirs to ‘..’ when  the
                     current  prefix  is  empty,  is a single ‘.’, or consists
                     only of a path beginning with ‘../’.  Otherwise the value
                     is ‘false’.

                             zstyle -e:completion:*special-dirs \[[ $PREFIX = (../)#(|.|..) ]] && reply=(..)squeeze-slashes
                     If  set to ‘true’, sequences of slashes in filename paths
                     (for example in ‘foo//bar’) will be treated as  a  single
                     slash.   This  is  the  usual  behaviour  of  UNIX paths.
                     However, by default the file completion function  behaves
                     as if there were a ‘*’ between the slashes.

              stop   If  set  to  ‘true’,  the _history_complete_word bindable
                     command will stop once when reaching the beginning or end
                     of  the  history.   Invoking  _history_complete_word will
                     then wrap around to the opposite end of the history.   If
                     this   style   is   set   to   ‘false’   (the   default),
                     _history_complete_word will loop immediately as in a menu
                     completion.

              strip-comments
                     If set to ‘true’, this style causes non-essential comment
                     text to be removed from completion matches.  Currently it
                     is  only  used  when completing e-mail addresses where it
                     removes any display name from the addresses, cutting them
                     down to plain user@host form.

              subst-globs-only
                     This  is  used by the _expand completer.  If it is set to
                     ‘true’, the expansion will only be used  if  it  resulted
                     from globbing; hence, if expansions resulted from the use
                     of the substitute style described below, but  these  were
                     not  further  changed by globbing, the expansions will be
                     rejected.

                     The default for this style is ‘false’.

              substitute
                     This boolean style controls whether the _expand completer
                     will  first try to expand all substitutions in the string
                     (such as ‘$(...)’ and ‘${...}’).

                     The default is ‘true’.

              suffix This is used by the _expand completer if the word  starts
                     with a tilde or contains a parameter expansion.  If it is
                     set to ‘true’, the word  will  only  be  expanded  if  it
                     doesn’t  have  a  suffix,  i.e.  if  it is something like
                     ‘~foo’ or  ‘$foo’  rather  than  ‘~foo/’  or  ‘$foo/bar’,
                     unless  that  suffix  itself contains characters eligible
                     for expansion.  The default for this style is ‘true’.

              tag-order
                     This provides  a  mechanism  for  sorting  how  the  tags
                     available in a particular context will be used.

                     The  values  for  the  style  are sets of space-separated
                     lists of tags.  The tags in each value will be  tried  at
                     the  same  time;  if no match is found, the next value is
                     used.  (See the file-patterns style for an  exception  to
                     this behavior.)

                     For example:

                             zstyle:completion:*:complete:-command-:*tag-order \commands functions’

                     specifies  that  completion  in  command  position  first
                     offers external commands and shell functions.   Remaining
                     tags will be tried if no completions are found.

                     In  addition  to  tag names, each string in the value may
                     take one of the following forms:

                      -      If any value consists of only a hyphen, then only
                             the  tags  specified  in  the  other  values  are
                             generated.   Normally  all  tags  not  explicitly
                             selected  are  tried  last  if the specified tags
                             fail to generate any matches.  This means that  a
                             single  value  consisting only of a single hyphen
                             turns off completion.

                     ! tags...
                             A  string  starting  with  an  exclamation   mark
                             specifies  names of tags that are not to be used.
                             The effect is the same as if all  other  possible
                             tags for the context had been listed.

                     tag:label ...
                             Here,  tag  is one of the standard tags and label
                             is an arbitrary name.  Matches are  generated  as
                             normal  but  the  name  label is used in contexts
                             instead of tag.  This  is  not  useful  in  words
                             starting with !.

                             If  the  label  starts  with a hyphen, the tag is
                             prepended to the label to form the name used  for
                             lookup.   This can be used to make the completion
                             system  try  a  certain  tag  more   than   once,
                             supplying   different  style  settings  for  each
                             attempt; see below for an example.

                     tag:label:description
                             As before, but description will replace the  ‘%d’
                             in  the  value of the format style instead of the
                             default description supplied  by  the  completion
                             function.   Spaces  in  the  description  must be
                             quoted with a backslash.   A  ‘%d’  appearing  in
                             description  is  replaced  with  the  description
                             given by the completion function.

                     In any of the forms above the tag may  be  a  pattern  or
                     several  patterns  in the form ‘{pat1,pat2...}’.  In this
                     case all matching tags will be used except for any  given
                     explicitly in the same string.

                     One  use  of  these  features is to try one tag more than
                     once, setting other styles differently on  each  attempt,
                     but  still  to  use  all the other tags without having to
                     repeat them all.  For  example,  to  make  completion  of
                     function   names  in  command  position  ignore  all  the
                     completion functions  starting  with  an  underscore  the
                     first time completion is tried:

                             zstyle:completion:*:*:-command-:*tag-order \functions:-non-comp *functions
                             zstyle:completion:*:functions-non-compignored-patterns_*’

                     On  the  first  attempt, all tags will be offered but the
                     functions tag will  be  replaced  by  functions-non-comp.
                     The ignored-patterns style is set for this tag to exclude
                     functions starting with an underscore.  If there  are  no
                     matches,  the second value of the tag-order style is used
                     which completes functions using  the  default  tag,  this
                     time presumably including all function names.

                     The  matches  for  one  tag  can  be split into different
                     groups.  For example:

                             zstyle:completion:*tag-order \options:-long:long\ options
                                  options:-short:short\ options
                                  options:-single-letter:single\ letter\ options’

                             zstyle ’:completion:*:options-long’ ignored-patterns ’[-+](|-|[^-]*)’
                             zstyle ’:completion:*:options-short’ ignored-patterns ’--*’ ’[-+]?’
                             zstyle ’:completion:*:options-single-letter’ ignored-patterns ’???*’

                     With the group-names style set,  options  beginning  with
                     ‘--’,  options  beginning  with  a  single ‘-’ or ‘+’ but
                     containing multiple characters, and single-letter options
                     will  be  displayed  in  separate  groups  with different
                     descriptions.

                     Another  use  of  patterns  is  to  try  multiple   match
                     specifications one after another.  The matcher-list style
                     offers something similar, but it is tested very early  in
                     the  completion  system and hence can’t be set for single
                     commands nor for more specific contexts.  Here is how  to
                     try  normal  completion  without  any match specification
                     and,  if  that  generates  no  matches,  try  again  with
                     case-insensitive  matching,  restricting  the  effect  to
                     arguments of the command foo:

                             zstyle:completion:*:*:foo:*tag-order*’ ’*:-casezstyle:completion:*-casematcherm:{a-z}={A-Z}’

                     First, all the tags offered when completing after foo are
                     tried  using  the  normal tag name.  If that generates no
                     matches, the second value of  tag-order  is  used,  which
                     tries all tags again except that this time each has -case
                     appended to its name for lookup of  styles.   Hence  this
                     time the value for the matcher style from the second call
                     to zstyle in the  example  is  used  to  make  completion
                     case-insensitive.

                     It is possible to use the -e option of the zstyle builtin
                     command to specify conditions for the use  of  particular
                     tags.  For example:

                             zstyle -e*:-command-:*tag-orderif [[ -n $PREFIX$SUFFIX ]]; then
                                   reply=( )
                                 else
                                   reply=( - )
                                 fi’

                     Completion  in command position will be attempted only if
                     the string typed so far is not  empty.   This  is  tested
                     using  the PREFIX special parameter; see zshcompwid for a
                     description  of  parameters  which  are  special   inside
                     completion  widgets.   Setting  reply  to  an empty array
                     provides the default behaviour  of  trying  all  tags  at
                     once;  setting  it  to  an array containing only a hyphen
                     disables  the  use  of  all  tags  and   hence   of   all
                     completions.

                     If no tag-order style has been defined for a context, the
                     strings  ‘(|*-)argument-*   (|*-)option-*   values’   and
                     ‘options’   plus  all  tags  offered  by  the  completion
                     function will be  used  to  provide  a  sensible  default
                     behavior  that  causes  arguments (whether normal command
                     arguments or arguments of options) to be completed before
                     option names for most commands.

              urls   This  is used together with the the urls tag by functions
                     completing URLs.

                     If the value consists of more than one string, or if  the
                     only  string  does  not  name  a  file  or directory, the
                     strings are used as the URLs to complete.

                     If the value contains only one string which is  the  name
                     of a normal file the URLs are taken from that file (where
                     the URLs may be separated by white space or newlines).

                     Finally,  if  the  only  string  in  the  value  names  a
                     directory,   the   directory  hierarchy  rooted  at  this
                     directory gives the completions.  The top level directory
                     should  be the file access method, such as ‘http’, ‘ftp’,
                     ‘bookmark’ and so on.  In many cases the  next  level  of
                     directories  will be a filename.  The directory hierarchy
                     can descend as deep as necessary.

                     For example,

                             zstyle:completion:*urls ~/.urls
                             mkdir -p ~/.urls/ftp/ftp.zsh.org/pub/development

                     allows completion  of  all  the  components  of  the  URL
                     ftp://ftp.zsh.org/pub/development after suitable commands
                     such as ‘netscape’ or ‘lynx’.  Note, however, that access
                     methods  and  files  are  completed separately, so if the
                     hosts  style  is  set  hosts  can  be  completed  without
                     reference to the urls style.

                     See the description in the function _urls itself for more
                     information (e.g. ‘more $^fpath/_urls(N)’).

              use-cache
                     If this is set, the completion caching layer is activated
                     for  any  completions which use it (via the _store_cache,
                     _retrieve_cache,  and  _cache_invalid  functions).    The
                     directory  containing the cache files can be changed with
                     the cache-path style.

              use-compctl
                     If this style is set to a string not equal to  false,  0,
                     no, and off, the completion system may use any completion
                     specifications defined with the compctl builtin  command.
                     If  the  style  is  unset,  this  is  done  only  if  the
                     zsh/compctl  module  is  loaded.   The  string  may  also
                     contain  the substring ‘first’ to use completions defined
                     with ‘compctl -T’, and the substring ‘default’ to use the
                     completion defined with ‘compctl -D’.

                     Note  that this is only intended to smooth the transition
                     from  compctl  to  the  new  completion  system  and  may
                     disappear in the future.

                     Note  also that the definitions from compctl will only be
                     used if there is no specific completion function for  the
                     command in question.  For example, if there is a function
                     _foo to complete arguments to the  command  foo,  compctl
                     will  never  be  invoked  for  foo.  However, the compctl
                     version  will  be  tried  if  foo   only   uses   default
                     completion.

              use-ip By default, the function _hosts that completes host names
                     strips IP addresses from entries read from host databases
                     such  as  NIS  and ssh files.  If this style is true, the
                     corresponding IP addresses  can  be  completed  as  well.
                     This  style  is  not  use  in any context where the hosts
                     style is set; note also it must be set before  the  cache
                     of   host   names   is  generated  (typically  the  first
                     completion attempt).

              use-perl
                     Various parts of the function system use awk  to  extract
                     words  from  files  or command output as this universally
                     available.  However, many versions of awk have  arbitrary
                     limits  on the size of input.  If this style is set, perl
                     will be used instead.  This is almost  always  preferable
                     if perl is available on your system.

                     Currently  this  is  only used in completions for ‘make’,
                     but  it  may   be   extended   depending   on   authorial
                     frustration.

              users  This  may  be set to a list of usernames to be completed.
                     If it is not set all usernames will be  completed.   Note
                     that  if  it  is  set  only  that  list  of users will be
                     completed; this is because on some systems  querying  all
                     users can take a prohibitive amount of time.

              users-hosts
                     The   values   of  this  style  should  be  of  the  form
                     ‘user@host’ or ‘user:host’. It is used for commands  that
                     need  pairs  of user- and hostnames.  These commands will
                     complete usernames  from  this  style  (only),  and  will
                     restrict  subsequent  hostname completion to hosts paired
                     with that user in one of the values of the style.

                     It is possible to group values for sets of commands which
                     allow  a  remote  login, such as rlogin and ssh, by using
                     the my-accounts  tag.   Similarly,  values  for  sets  of
                     commands  which  usually  refer  to the accounts of other
                     people, such as talk and finger, can be grouped by  using
                     the other-accounts tag.  More ambivalent commands may use
                     the accounts tag.

              users-hosts-ports
                     Like users-hosts but used for commands  like  telnet  and
                     containing strings of the form ‘user@host:port’.

              verbose
                     If  set,  as  it is by default, the completion listing is
                     more  verbose.   In   particular   many   commands   show
                     descriptions for options if this style is ‘true’.

              word   This  is  used by the _list completer, which prevents the
                     insertion  of  completions  until  a  second   completion
                     attempt when the line has not changed.  The normal way of
                     finding out if the line has changed  is  to  compare  its
                     entire contents between the two occasions.  If this style
                     is true, the comparison is instead performed only on  the
                     current  word.   Hence  if  completion  is  performed  on
                     another word with the same contents, completion will  not
                     be delayed.

CONTROL FUNCTIONS

       The  initialization  script  compinit  redefines  all the widgets which
       perform completion to call the supplied widget function _main_complete.
       This  function  acts  as  a  wrapper  calling the so-called ‘completer’
       functions that generate matches.   If  _main_complete  is  called  with
       arguments,  these  are  taken as the names of completer functions to be
       called in the order given.  If no  arguments  are  given,  the  set  of
       functions  to  try  is taken from the completer style.  For example, to
       use normal completion and  correction  if  that  doesn’t  generate  any
       matches:

              zstyle:completion:*completer _complete _correct

       after  calling compinit. The default value for this style is ‘_complete
       _ignored’, i.e. normally only ordinary completion is tried, first  with
       the  effect  of  the  ignored-patterns  style and then without it.  The
       _main_complete  function  uses  the  return  status  of  the  completer
       functions  to  decide  if  other  completers  should be called.  If the
       return  status  is  zero,  no  other  completers  are  tried  and   the
       _main_complete function returns.

       If  the  first  argument  to  _main_complete  is  a  single hyphen, the
       arguments will not be taken  as  names  of  completers.   Instead,  the
       second  argument  gives  a  name  to  use in the completer field of the
       context and the other arguments give a command name  and  arguments  to
       call to generate the matches.

       The  following  completer  functions are contained in the distribution,
       although users may write their own.  Note that in contexts the  leading
       underscore  is  stripped,  for example basic completion is performed in
       the context ‘:completion::complete:...’.

       _all_matches
              This completer can be used to add a  string  consisting  of  all
              other matches.  As it influences later completers it must appear
              as the first completer in the list.  The list of all matches  is
              affected by the avoid-completer and old-matches styles described
              above.

              It may be useful to use the _generic function described below to
              bind _all_matches to its own keystroke, for example:

                     zle -C all-matches complete-word _generic
                     bindkey^Xaall-matches
                     zstyle:completion:all-matches:*old-matches only
                     zstyle:completion:all-matches::::completer _all_matches

              Note  that  this does not generate completions by itself.  First
              use  any  of  the  standard  ways  of  generating  a   list   of
              completions, then use ^Xa to show all matches.

       _approximate
              This  is similar to the basic _complete completer but allows the
              completions to  undergo  corrections.   The  maximum  number  of
              errors  can  be  specified  by  the  max-errors  style;  see the
              description of approximate matching in zshexpn(1) for how errors
              are  counted.   Normally this completer will only be tried after
              the normal _complete completer:

                     zstyle:completion:*completer _complete _approximate

              This will give correcting  completion  if  and  only  if  normal
              completion  yields  no  possible  completions.   When  corrected
              completions are found, the completer will  normally  start  menu
              completion allowing you to cycle through these strings.

              This  completer  uses  the  tags  corrections  and original when
              generating the possible corrections  and  the  original  string.
              The  format  style  for  the  former  may contain the additional
              sequences ‘%e’ and ‘%o’ which will be replaced by the number  of
              errors  accepted  to  generate  the corrections and the original
              string, respectively.

              The completer  progressively  increases  the  number  of  errors
              allowed  up  to  the  limit  by the max-errors style, hence if a
              completion is found with one  error,  no  completions  with  two
              errors will be shown, and so on.  It modifies the completer name
              in the context to indicate the number of errors being tried:  on
              the  first  try the completer field contains ‘approximate-1’, on
              the second try ‘approximate-2’, and so on.

              When _approximate is called from another function, the number of
              errors to accept may be passed with the -a option.  The argument
              is in the same format  as  the  max-errors  style,  all  in  one
              string.

              Note  that  this completer (and the _correct completer mentioned
              below) can be quite expensive to call, especially when  a  large
              number  of  errors are allowed.  One way to avoid this is to set
              up the completer style using the -e option  to  zstyle  so  that
              some  completers  are  only  used when completion is attempted a
              second time on the same string, e.g.:

                     zstyle -e:completion:*completerif [[ $_last_try != "$HISTNO$BUFFER$CURSOR" ]]; then
                         _last_try="$HISTNO$BUFFER$CURSOR"
                         reply=(_complete _match _prefix)
                       else
                         reply=(_ignored _correct _approximate)
                       fi’

              This uses the HISTNO parameter and the BUFFER and CURSOR special
              parameters  that are available inside zle and completion widgets
              to find out if the command line hasn’t changed  since  the  last
              time completion was tried.  Only then are the _ignored, _correct
              and _approximate completers called.

       _complete
              This  completer  generates  all  possible   completions   in   a
              context-sensitive  manner,  i.e. using the settings defined with
              the compdef function explained above and the current settings of
              all  special  parameters.   This  gives  the  normal  completion
              behaviour.

              To complete arguments of commands, _complete  uses  the  utility
              function  _normal,  which is in turn responsible for finding the
              particular function; it is described below.  Various contexts of
              the  form  -context-  are  handled  specifically.  These are all
              mentioned above as possible arguments to the #compdef tag.

              Before trying  to  find  a  function  for  a  specific  context,
              _complete  checks if the parameter ‘compcontext’ is set. Setting
              ‘compcontext’ allows the  usual  completion  dispatching  to  be
              overridden  which  is  useful  in places such as a function that
              uses vared for input. If it is set to an array, the elements are
              taken  to  be the possible matches which will be completed using
              the tag ‘values’ and the description ‘value’. If it is set to an
              associative array, the keys are used as the possible completions
              and the values (if non-empty) are used as descriptions  for  the
              matches.  If ‘compcontext’ is set to a string containing colons,
              it should be of the form ‘tag:descr:action’.  In this  case  the
              tag and descr give the tag and description to use and the action
              indicates what should be completed in one of the forms  accepted
              by the _arguments utility function described below.

              Finally, if ‘compcontext’ is set to a string without colons, the
              value is taken as the  name  of  the  context  to  use  and  the
              function  defined  for  that  context  will be called.  For this
              purpose, there is a special context  named  -command-line-  that
              completes  whole  command  lines (commands and their arguments).
              This is  not  used  by  the  completion  system  itself  but  is
              nonetheless handled when explicitly called.

       _correct
              Generate corrections, but not completions, for the current word;
              this is similar to _approximate but will not allow any number of
              extra  characters  at  the  cursor  as that completer does.  The
              effect  is  similar  to  spell-checking.    It   is   based   on
              _approximate,  but  the  completer  field in the context name is
              correct.

              For example, with:

                     zstyle:completion:::::completer _complete _correct _approximate
                     zstyle:completion:*:correct:::max-errors 2 not-numeric
                     zstyle:completion:*:approximate:::max-errors 3 numeric

              correction will accept up to two errors.  If a numeric  argument
              is  given,  correction  will  not  be  performed, but correcting
              completion will be, and will accept as many errors as  given  by
              the   numeric  argument.   Without  a  numeric  argument,  first
              correction and then correcting completion will  be  tried,  with
              the  first one accepting two errors and the second one accepting
              three errors.

              When _correct is called as a function, the number of  errors  to
              accept may be given following the -a option.  The argument is in
              the same form a values to the accept style, all in one string.

              This completer function is  intended  to  be  used  without  the
              _approximate  completer  or,  as in the example, just before it.
              Using it after  the  _approximate  completer  is  useless  since
              _approximate  will  at  least  generate  the  corrected  strings
              generated by the _correct completer -- and probably more.

       _expand
              This completer function does not really perform completion,  but
              instead  checks  if the word on the command line is eligible for
              expansion and, if it is, gives detailed control  over  how  this
              expansion  is  done.   For this to happen, the completion system
              needs to be invoked with complete-word,  not  expand-or-complete
              (the  default  binding for TAB), as otherwise the string will be
              expanded by the shell’s internal mechanism before the completion
              system  is  started.   Note also this completer should be called
              before the _complete completer function.

              The tags used when generating expansions are all-expansions  for
              the  string  containing all possible expansions, expansions when
              adding the possible expansions as single  matches  and  original
              when  adding  the  original  string from the line.  The order in
              which these strings are generated, if at all, can be  controlled
              by the group-order and tag-order styles, as usual.

              The  format  string  for  all-expansions  and for expansions may
              contain the sequence ‘%o’ which will be replaced by the original
              string from the line.

              The  kind  of  expansion  to  be  tried  is  controlled  by  the
              substitute, glob and subst-globs-only styles.

              It is also possible to call _expand as a function, in which case
              the  different  modes  may  be  selected  with  options:  -s for
              substitute, -g for glob and -o for subst-globs-only.

       _expand_alias
              If the word the cursor is on is an alias, it is expanded and  no
              other  completers are called.  The types of aliases which are to
              be expanded can be controlled with the  styles  regular,  global
              and disabled.

              This  function  is  also  a  bindable  command,  see the section
              ‘Bindable Commands’ below.

       _history
              Complete  words  from  the  shell’s  command    history.    This
              completer  can  be  controlled  by the remove-all-dups, and sort
              styles as for the _history_complete_word bindable  command,  see
              the   section   ‘Bindable   Commands’   below  and  the  section
              ‘Completion System Configuration’ above.

       _ignored
              The ignored-patterns style can be set  to  a  list  of  patterns
              which  are  compared against possible completions; matching ones
              are  removed.   With  this  completer  those  matches   can   be
              reinstated,  as  if  no  ignored-patterns  style  were set.  The
              completer actually generates its  own  list  of  matches;  which
              completers  are invoked is determined in the same way as for the
              _prefix completer.  The single-ignored style is  also  available
              as described above.

       _list  This  completer  allows  the  insertion of matches to be delayed
              until completion is attempted a second time without the word  on
              the  line being changed.  On the first attempt, only the list of
              matches will be shown.  It is affected by the  styles  condition
              and  word,  see  the  section  ‘Completion System Configuration’
              above.

       _match This completer is  intended  to  be  used  after  the  _complete
              completer.   It  behaves similarly but the string on the command
              line may be a pattern to match against trial completions.   This
              gives the effect of the GLOB_COMPLETE option.

              Normally completion will be performed by taking the pattern from
              the line, inserting a ‘*’ at the cursor position  and  comparing
              the  resulting  pattern with the possible completions generated.
              This can be modified with  the  match-original  style  described
              above.

              The  generated  matches  will  be  offered  in a menu completion
              unless the insert-unambiguous style is set to  ‘true’;  see  the
              description above for other options for this style.

              Note that matcher specifications defined globally or used by the
              completion functions (the styles matcher-list and matcher)  will
              not be used.

       _menu  This  completer  was  written as simple example function to show
              how menu completion can be enabled in shell  code.  However,  it
              has  the notable effect of disabling menu selection which can be
              useful with _generic based widgets. It should  be  used  as  the
              first  completer  in the list.  Note that this is independent of
              the setting of the MENU_COMPLETE option and does not  work  with
              the other menu completion widgets such as reverse-menu-complete,
              or accept-and-menu-complete.

       _oldlist
              This completer controls  how  the  standard  completion  widgets
              behave  when  there is an existing list of completions which may
              have  been  generated  by   a   special   completion   (i.e.   a
              separately-bound  completion  command).   It allows the ordinary
              completion keys to continue to use the list of completions  thus
              generated,   instead   of  producing  a  new  list  of  ordinary
              contextual  completions.   It  should  appear  in  the  list  of
              completers before any of the widgets which generate matches.  It
              uses  two  styles:  old-list  and  old-menu,  see  the   section
              ‘Completion System Configuration’ above.

       _prefix
              This  completer  can  be  used to try completion with the suffix
              (everything after the cursor)  ignored.   In  other  words,  the
              suffix  will  not  be  considered  to  be  part  of  the word to
              complete.      The     effect     is     similar     to      the
              expand-or-complete-prefix command.

              The completer style is used to decide which other completers are
              to be called to generate matches.  If this style is  unset,  the
              list  of  completers  set  for  the  current  context is used --
              except, of course, the _prefix completer  itself.   Furthermore,
              if  this  completer  appears  more  than  once  in  the  list of
              completers only those completers not already tried by  the  last
              invocation of _prefix will be called.

              For example, consider this global completer style:

                     zstyle:completion:*completer \
                         _complete _prefix _correct _prefix:foo

              Here, the _prefix completer tries normal completion but ignoring
              the suffix.  If that doesn’t generate any matches,  and  neither
              does  the  call to the _correct completer after it, _prefix will
              be called a second time and, now only trying correction with the
              suffix  ignored.  On the second invocation the completer part of
              the context appears as ‘foo’.

              To use _prefix as the last resort and try only normal completion
              when it is invoked:

                     zstyle:completion:*completer _complete ... _prefix
                     zstyle:completion::prefix:*completer _complete

              The  add-space  style is also respected.  If it is set to ‘true’
              then _prefix will insert a space between the  matches  generated
              (if any) and the suffix.

              Note  that this completer is only useful if the COMPLETE_IN_WORD
              option is set; otherwise, the cursor will be moved to the end of
              the  current word before the completion code is called and hence
              there will be no suffix.

       bashcompinit
              This function provides compatibility  with  bash’s  programmable
              completion  system.   When  run  it  will  define the functions,
              compgen and complete which correspond to the bash builtins  with
              the  same  names.   It  will  then be possible to use completion
              specifications and functions written for bash.

BINDABLE COMMANDS

       In addition to the context-dependent completions  provided,  which  are
       expected to work in an intuitively obvious way, there are a few widgets
       implementing special behaviour which can be bound separately  to  keys.
       The following is a list of these and their default bindings.

       _bash_completions
              This  function  is  used by two widgets, _bash_complete-word and
              _bash_list-choices.  It exists  to  provide  compatibility  with
              completion  bindings in bash.  The last character of the binding
              determines  what  is  completed:  ‘!’,   command   names;   ‘$’,
              environment  variables;  ‘@’,  host  names; ‘/’, file names; ‘~’
              user names.   In  bash,  the  binding  preceded  by  ‘\e’  gives
              completion,  and  preceded  by  ‘^X’  lists options.  As some of
              these bindings clash with standard zsh bindings, only ‘\e~’  and
              ‘^X~’  are  bound  by  default.   To add the rest, the following
              should be added to .zshrc after compinit has been run:

                     for key in!’ ’$’ ’@’ ’/’ ’~; do
                       bindkey "\e$key" _bash_complete-word
                       bindkey "^X$key" _bash_list-choices
                     done

              This includes the bindings for ‘~’ in  case  they  were  already
              bound  to  something else; the completion code does not override
              user bindings.

       _correct_filename (^XC)
              Correct the filename path at the cursor position.  Allows up  to
              six  errors in the name.  Can also be called with an argument to
              correct a filename path, independently of zle; the correction is
              printed on standard output.

       _correct_word (^Xc)
              Performs  correction  of  the  current  argument using the usual
              contextual completions as  possible  choices.  This  stores  the
              string  ‘correct-word’ in the function field of the context name
              and then calls the _correct completer.

       _expand_alias (^Xa)
              This function can be used as  a  completer  and  as  a  bindable
              command.   It  expands  the  word  the  cursor is on if it is an
              alias.  The types of alias expanded can be controlled  with  the
              styles regular, global and disabled.

              When  used as a bindable command there is one additional feature
              that can be selected by setting the complete  style  to  ‘true’.
              In  this  case,  if  the  word  is  not  the  name  of an alias,
              _expand_alias tries to complete the word to a  full  alias  name
              without  expanding  it.  It leaves the cursor directly after the
              completed word so that invoking  _expand_alias  once  more  will
              expand the now-complete alias name.

       _expand_word (^Xe)
              Performs  expansion  on  the  current  word:   equivalent to the
              standard expand-word command, but using the  _expand  completer.
              Before  calling  it, the function field of the context is set to
              ‘expand-word’.

       _generic
              This function is not defined  as  a  widget  and  not  bound  by
              default.   However,  it  can be used to define a widget and will
              then store the name of the widget in the function field  of  the
              context  and  call  the  completion  system.  This allows custom
              completion widgets with their own set of style  settings  to  be
              defined  easily.   For example, to define a widget that performs
              normal completion and starts menu selection:

                     zle -C foo complete-word _generic
                     bindkey...foo
                     zstyle:completion:foo:*menu yes select=1

              Note in particular that the completer style may be set  for  the
              context in order to change the set of functions used to generate
              possible matches.  If _generic is called with  arguments,  those
              are  passed  through to _main_complete as the list of completers
              in place of those defined by the completer style.

       _history_complete_word (\e/)
              Complete words from the shell’s command history. This  uses  the
              list, remove-all-dups, sort, and stop styles.

       _most_recent_file (^Xm)
              Complete  the  name  of the most recently modified file matching
              the pattern on the command line (which may be blank).  If  given
              a  numeric  argument  N, complete the Nth most recently modified
              file.  Note the completion, if any, is always unique.

       _next_tags (^Xn)
              This command alters the set of matches used to that for the next
              tag,  or  set of tags, either as given by the tag-order style or
              as  set  by  default;  these  matches  would  otherwise  not  be
              available.   Successive invocations of the command cycle through
              all possible sets of tags.

       _read_comp (^X^R)
              Prompt the user for a string, and use that to perform completion
              on  the  current  word.   There  are  two  possibilities for the
              string.  First, it can be a set  of  words  beginning  ‘_’,  for
              example  ‘_files  -/’,  in  which  case  the  function  with any
              arguments  will  be  called   to   generate   the   completions.
              Unambiguous  parts  of  the  function  name  will  be  completed
              automatically (normal completion is not available at this point)
              until a space is typed.

              Second, any other string will be passed as a set of arguments to
              compadd and should hence be an expression specifying what should
              be completed.

              A  very  restricted  set  of  editing commands is available when
              reading the string:  ‘DEL’ and ‘^H’ delete the  last  character;
              ‘^U’  deletes  the  line,  and ‘^C’ and ‘^G’ abort the function,
              while ‘RET’ accepts the completion.  Note  the  string  is  used
              verbatim  as  a  command  line,  so  arguments must be quoted in
              accordance with standard shell rules.

              Once a string has been read, the next call  to  _read_comp  will
              use  the existing string instead of reading a new one.  To force
              a new  string  to  be  read,  call  _read_comp  with  a  numeric
              argument.

       _complete_debug (^X?)
              This  widget  performs  ordinary  completion,  but captures in a
              temporary file a trace of the shell  commands  executed  by  the
              completion  system.   Each completion attempt gets its own file.
              A command to view each of these files is pushed onto the  editor
              buffer stack.

       _complete_help (^Xh)
              This  widget  displays  information about the context names, the
              tags, and the completion functions used when completing  at  the
              current  cursor position. If given a numeric argument other than
              1 (as in ‘ESC-2 ^Xh’), then the styles used and the contexts for
              which they are used will be shown, too.

              Note  that  the  information  about styles may be incomplete; it
              depends  on  the  information  available  from  the   completion
              functions  called, which in turn is determined by the user’s own
              styles and other settings.

       _complete_tag (^Xt)
              This widget completes symbol tags created by the etags or  ctags
              programmes  (note  there  is  no  connection with the completion
              system’s tags) stored in a file TAGS,  in  the  format  used  by
              etags,  or  tags,  in the format created by ctags.  It will look
              back up the path hierarchy for the first  occurrence  of  either
              file;  if  both  exist,  the  file  TAGS  is preferred.  You can
              specify the full path to a TAGS or  tags  file  by  setting  the
              parameter    $TAGSFILE    or    $tagsfile   respectively.    The
              corresponding completion tags used are etags  and  vtags,  after
              emacs and vi respectively.

UTILITY FUNCTIONS

       Descriptions  follow  for  utility  functions  that  may be useful when
       writing  completion  functions.   If   functions   are   installed   in
       subdirectories,  most  of  these reside in the Base subdirectory.  Like
       the example functions for commands in  the  distribution,  the  utility
       functions  generating  matches  all  follow the convention of returning
       status zero if they generated completions and non-zero if  no  matching
       completions could be added.

       Two  more  features  are  offered  by the _main_complete function.  The
       arrays compprefuncs and comppostfuncs may contain  names  of  functions
       that  are  to be called immediately before or after completion has been
       tried.  A function will  only  be  called  once  unless  it  explicitly
       reinserts itself into the array.

       _all_labels [ -x ] [ -12VJ ] tag name descr [ command args ... ]
              This  is  a  convenient  interface  to  the _next_label function
              below, implementing the loop shown in the  _next_label  example.
              The  command  and  its  arguments  are  called  to  generate the
              matches.   The  options  stored  in  the  parameter  name   will
              automatically  be  inserted into the args passed to the command.
              Normally, they are put directly after the command, but if one of
              the  args  is a single hyphen, they are inserted directly before
              that.  If the hyphen is the last argument, it  will  be  removed
              from  the  argument  list  before  the  command is called.  This
              allows _all_labels to be used in  almost  all  cases  where  the
              matches can be generated by a single call to the compadd builtin
              command or by a call to one of the utility functions.

              For example:

                     local expl
                     ...
                     if _requested foo; then
                       ...
                       _all_labels foo expl...compadd ... - $matches
                     fi

              Will complete the strings  from  the  matches  parameter,  using
              compadd  with additional options which will take precedence over
              those generated by _all_labels.

       _alternative [ -C name ] spec ...
              This function is useful in simple cases where multiple tags  are
              available.   Essentially  it  implements  a  loop  like  the one
              described for the _tags function below.

              The tags to use and the action to perform if a tag is  requested
              are   described   using   the  specs  which  are  of  the  form:
              ‘tag:descr:action’.  The tags are offered using _tags and if the
              tag  is  requested,  the  action  is  executed  with  the  given
              description descr.   The  actions  are  those  accepted  by  the
              _arguments  function  (described below), excluding the ‘->state’
              and ‘=...’ forms.

              For example, the action may be a simple function call:

                     _alternative \users:user:_users\hosts:host:_hosts’

              offers usernames and hostnames as possible matches, generated by
              the _users and _hosts functions respectively.

              Like  _arguments, this functions uses _all_labels to execute the
              actions, which  will  loop  over  all  sets  of  tags.   Special
              handling  is  only required if there is an additional valid tag,
              for example inside a function called from _alternative.

              Like _tags this function  supports  the  -C  option  to  give  a
              different name for the argument context field.

       _arguments [ -nswWACRS ] [ -O name ] [ -M matchspec ] [ : ] spec ...
              This  function  can be used to give a complete specification for
              completion for a command whose arguments  follow  standard  UNIX
              option  and  argument  conventions.  The following forms specify
              individual sets of options and arguments;  to  avoid  ambiguity,
              these  may be separated from the options to _arguments itself by
              a single  colon.   Options  to  _arguments  itself  must  be  in
              separate words, i.e. -s -w, not -sw.

              With the option -n, _arguments sets the parameter NORMARG to the
              position of the first normal argument in the $words array,  i.e.
              the position after the end of the options.  If that argument has
              not been reached, NORMARG is  set  to  -1.   The  caller  should
              declare  ‘integer NORMARG’ if the -n option is passed; otherwise
              the parameter is not used.

              n:message:action
              n::message:action
                     This describes the n’th  normal  argument.   The  message
                     will  be  printed  above  the  matches  generated and the
                     action indicates what can be completed in  this  position
                     (see  below).  If there are two colons before the message
                     the argument is optional.  If the message  contains  only
                     white  space,  nothing  will be printed above the matches
                     unless the action adds an explanation string itself.

              :message:action
              ::message:action
                     Similar, but describes the next argument, whatever number
                     that  happens  to  be.  If all arguments are specified in
                     this  form  in  the  correct  order   the   numbers   are
                     unnecessary.

              *:message:action
              *::message:action
              *:::message:action
                     This   describes   how   arguments   (usually  non-option
                     arguments, those not beginning with - or  +)  are  to  be
                     completed  when  neither  of  the  first  two  forms  was
                     provided.  Any number of arguments can  be  completed  in
                     this fashion.

                     With  two  colons  before  the message, the words special
                     array and the CURRENT special parameter are  modified  to
                     refer  only  to  the  normal arguments when the action is
                     executed or evaluated.   With  three  colons  before  the
                     message  they  are  modified  to refer only to the normal
                     arguments covered by this description.

              optspec
              optspec:...
                     This describes an option.  The colon  indicates  handling
                     for  one  or  more  arguments to the option; if it is not
                     present, the option is assumed to take no arguments.

                     By default, options are multi-character name, one ‘-word’
                     per  option.   With -s, options may be single characters,
                     with more  than  one  option  per  word,  although  words
                     starting  with two hyphens, such as ‘--prefix’, are still
                     considered complete option names.  This is  suitable  for
                     standard GNU options.

                     The  combination  of  -s  with  -w  allows  single-letter
                     options to be combined in a single word even  if  one  or
                     more  of  the options take arguments.  For example, if -a
                     takes an argument, with no -s-ab’ is  considered  as  a
                     single  (unhandled) option; with -s -ab is an option with
                     the argument ‘b’; with both -s and -w,  -ab  may  be  the
                     option -a and the option -b with arguments still to come.

                     The option -W takes this a stage further:  it is possible
                     to  complete single-letter options even after an argument
                     that occurs in the same word.  However, it depends on the
                     action performed whether options will really be completed
                     at this point.  For more control, use a utility  function
                     like _guard as part of the action.

                     The   following  forms  are  available  for  the  initial
                     optspec, whether or not the option has arguments.

                     *optspec
                             Here optspec is one of the remaining forms below.
                             This  indicates  the  following  optspec  may  be
                             repeated.  Otherwise if the corresponding  option
                             is  already  present  on  the command line to the
                             left of the cursor it will not be offered  again.

                     -optname
                     +optname
                             In  the  simplest  form  the  optspec is just the
                             option name beginning with  a  minus  or  a  plus
                             sign, such as ‘-foo’.  The first argument for the
                             option (if any) must follow as  a  separate  word
                             directly after the option.

                             Either of ‘-+optname’ and ‘+-optname’ can be used
                             to specify that -optname and  +optname  are  both
                             valid.

                             In  all  the remaining forms, the leading ‘-’ may
                             be replaced by or paired with ‘+’ in this way.

                     -optname-
                             The  first  argument  of  the  option  must  come
                             directly  after the option name in the same word.
                             For  example,  ‘-foo-:...’  specifies  that   the
                             completed  option  and  argument  will  look like
                             ‘-fooarg’.

                     -optname+
                             The first argument may appear  immediately  after
                             optname  in  the  same  word,  or may appear as a
                             separate word after  the  option.   For  example,
                             ‘-foo+:...’  specifies  that the completed option
                             and argument will look like either  ‘-fooarg’  or
                             ‘-foo arg’.

                     -optname=
                             The  argument  may appear as the next word, or in
                             same word as the option name provided that it  is
                             separated  from it by an equals sign, for example
                             ‘-foo=arg’ or ‘-foo arg’.

                     -optname=-
                             The argument to the option must appear  after  an
                             equals  sign  in  the  same  word, and may not be
                             given in the next argument.

                     optspec[explanation]
                             An explanation string may be appended to  any  of
                             the preceding forms of optspec by enclosing it in
                             brackets, as in ‘-q[query operation]’.

                             The verbose style is used to decide  whether  the
                             explanation strings are displayed with the option
                             in a completion listing.

                             If no bracketed explanation string is  given  but
                             the  auto-description  style  is set and only one
                             argument is described for this optspec, the value
                             of the style is displayed, with any appearance of
                             the sequence ‘%d’ in it replaced by  the  message
                             of the first optarg that follows the optspec; see
                             below.

              It is possible for options with a literal ‘+’ or ‘=’ to  appear,
              but that character must be quoted, for example ‘-\+’.

              Each  optarg following an optspec must take one of the following
              forms:

              :message:action
              ::message:action
                     An argument to the option; message and action are treated
                     as  for  ordinary  arguments.   In  the  first  form, the
                     argument is mandatory, and  in  the  second  form  it  is
                     optional.

                     This  group  may  be  repeated  for  options  which  take
                     multiple      arguments.       In      other       words,
                     :message1:action1:message2:action2   specifies  that  the
                     option takes two arguments.

              :*pattern:message:action
              :*pattern::message:action
              :*pattern:::message:action
                     This describes multiple arguments.  Only the last  optarg
                     for  an  option taking multiple arguments may be given in
                     this form.  If the pattern is empty (i.e., :*:), all  the
                     remaining  words  on  the  line  are  to  be completed as
                     described by the action; otherwise, all the words  up  to
                     and  including  a  word  matching  the  pattern are to be
                     completed using the action.

                     Multiple colons are treated as for the ‘*:...’ forms  for
                     ordinary  arguments:  when the message is preceded by two
                     colons, the words special array and the  CURRENT  special
                     parameter are modified during the execution or evaluation
                     of the action to  refer  only  to  the  words  after  the
                     option.  When preceded by three colons, they are modified
                     to refer only to the words covered by this description.

       Any literal colon in an optname, message, or action must be preceded by
       a backslash, ‘\:’.

       Each  of  the  forms  above may be preceded by a list in parentheses of
       option names and argument numbers.  If  the  given  option  is  on  the
       command  line,  the options and arguments indicated in parentheses will
       not be offered.  For example, ‘(-two -three 1)-one:...’  completes  the
       option  ‘-one’;  if  this appears on the command line, the options -two
       and -three and the first ordinary argument will not be completed  after
       it.   ‘(-foo):...’ specifies an ordinary argument completion; -foo will
       not be completed if that argument is already present.

       Other items may appear in the list  of  excluded  options  to  indicate
       various  other  items  that  should  not  be  applied  when the current
       specification is matched: a single star  (*)  for  the  rest  arguments
       (i.e.  a specification of the form ‘*:...’); a colon (:) for all normal
       (non-option-) arguments;  and  a  hyphen  (-)  for  all  options.   For
       example,  if  ‘(*)’  appears before an option and the option appears on
       the command line, the list of remaining arguments (those shown  in  the
       above table beginning with ‘*:’) will not be completed.

       To aid in reuse of specifications, it is possible to precede any of the
       forms above with ‘!’; then  the  form  will  no  longer  be  completed,
       although  if  the  option  or argument appears on the command line they
       will be skipped as normal.  The main use for this is when the arguments
       are  given  by  an  array, and _arguments is called repeatedly for more
       specific contexts: on the first call  ‘_arguments  $global_options’  is
       used, and on subsequent calls ‘_arguments !$^global_options’.

       In each of the forms above the action determines how completions should
       be generated.  Except for the ‘->string’ form below, the action will be
       executed by calling the _all_labels function to process all tag labels.
       No special handling of tags is needed unless a function call introduces
       a new one.

       The forms for action are as follows.

         (single unquoted space)
              This  is  useful  where  an  argument  is required but it is not
              possible or desirable to generate matches for it.   The  message
              will  be displayed but no completions listed.  Note that even in
              this case the colon at the end of the message is needed; it  may
              only be omitted when neither a message nor an action is given.

       (item1 item2 ...)
              One of a list of possible matches, for example:

                     :foo:(foo bar baz)

       ((item1\:desc1 ...))
              Similar  to  the  above, but with descriptions for each possible
              match.  Note the backslash before the colon.  For example,

                     :foo:((a\:bar b\:baz))

              The matches will be listed together with their  descriptions  if
              the description style is set with the values tag in the context.

       ->string
              In this form, _arguments processes the arguments and options and
              then returns control to the calling function with parameters set
              to indicate the state of processing; the calling  function  then
              makes  its  own  arrangements  for  generating completions.  For
              example, functions that implement a state machine can  use  this
              type of action.

              Where  _arguments  encounters  a  ‘->string’,  it will strip all
              leading and trailing whitespace from string and  set  the  array
              state  to  the  set of all stringss for which an action is to be
              performed.

              By default and in common with all other well behaved  completion
              functions,  _arguments returns status zero if it was able to add
              matches and non-zero otherwise. However, if  the  -R  option  is
              given,  _arguments  will  instead  return  a  status  of  300 to
              indicate that $state is to be handled.

              In  addition  to  $state,  _arguments  also  sets   the   global
              parameters  ‘context’, ‘line’ and ‘opt_args’ as described below,
              and does not reset any changes made to  the  special  parameters
              such  as  PREFIX and words.  This gives the calling function the
              choice of resetting these parameters or propagating  changes  in
              them.

              A   function   calling  _arguments  with  at  least  one  action
              containing a ‘->string’ therefore must declare appropriate local
              parameters:

                     local context state line
                     typeset -A opt_args

              to avoid _arguments from altering the global environment.

       {eval-string}
              A  string  in  braces  is  evaluated  as  shell code to generate
              matches.  If the eval-string  itself  does  not  begin  with  an
              opening  parenthesis  or  brace  it is split into separate words
              before execution.

       = action
              If the action starts with ‘= ’ (an equals  sign  followed  by  a
              space),  _arguments  will  insert  the  contents of the argument
              field of the current context as the new  first  element  in  the
              words  special  array  and  increment  the  value of the CURRENT
              special parameter.  This has the effect  of  inserting  a  dummy
              word  onto  the  completion  command line while not changing the
              point at which completion is taking place.

              This is most useful with one of the specifiers that restrict the
              words on the command line on which the action is to operate (the
              two- and three-colon forms above).  One particular use  is  when
              an  action itself causes _arguments on a restricted range; it is
              necessary to use this trick to  insert  an  appropriate  command
              name into the range for the second call to _arguments to be able
              to parse the line.

        word...
       word...
              This covers all forms other than those  above.   If  the  action
              starts with a space, the remaining list of words will be invoked
              unchanged.

              Otherwise it will be invoked  with  some  extra  strings  placed
              after  the first word; these are to be passed down as options to
              the compadd builtin.  They ensure that the  state  specified  by
              _arguments,  in  particular  the  descriptions  of  options  and
              arguments, is correctly passed to the completion command.  These
              additional  arguments are taken from the array parameter ‘expl’;
              this will be set up before executing the action and hence may be
              referred  to  inside  it,  typically in an expansion of the form
              ‘$expl[@]’ which preserves empty elements of the array.

       During the performance of the action the array ‘line’ will  be  set  to
       the  command  name and normal arguments from the command line, i.e. the
       words from the command line excluding all options and their  arguments.
       Options  are  stored  in  the  associative array ‘opt_args’ with option
       names as keys and their arguments as the values.  For options that have
       more  than  one  argument  these  are given as one string, separated by
       colons.  All  colons  in  the  original  arguments  are  preceded  with
       backslashes.

       The  parameter  ‘context’ is set when returning to the calling function
       to perform an action of the form ‘->string’.  It is set to an array  of
       elements  corresponding  to  the elements of $state.  Each element is a
       suitable name for the argument field of the context: either a string of
       the  form ‘option-opt-n’ for the n’th argument of the option -opt, or a
       string of the form ‘argument-n’ for  the  n’th  argument.   For  ‘rest’
       arguments,  that  is  those  in  the  list  at  the  end not handled by
       position, n is the string ‘rest’.  For  example,  when  completing  the
       argument  of  the  -o  option,  the name is ‘option-o-1’, while for the
       second normal (non-option-) argument it is ‘argument-2’.

       Furthermore, during the evaluation of the action the  context  name  in
       the  curcontext  parameter is altered to append the same string that is
       stored in the context parameter.

       It is possible to specify multiple sets of options and  arguments  with
       the  sets  separated  by single hyphens.  The specifications before the
       first hyphen (if any) are shared by all the remaining sets.  The  first
       word in every other set provides a name for the set which may appear in
       exclusion lists in specifications, either alone or before  one  of  the
       possible  values  described  above.   In  the  second case a ‘-’ should
       appear between this name and the remainder.

       For example:

              _arguments \
                  -a \
                - set1 \
                  -c \
                - set2 \
                  -d \:arg:(x2 y2)’

       This defines two sets.  When the command line contains the option ‘-c’,
       the  ‘-d’  option  and  the  argument  will  not be considered possible
       completions.  When it contains ‘-d’ or an  argument,  the  option  ‘-c’
       will  not  be  considered.  However, after ‘-a’ both sets will still be
       considered valid.

       If the name given for one of the mutually exclusive sets is of the form
       ‘(name)’ then only one value from each set will ever be completed; more
       formally, all  specifications  are  mutually  exclusive  to  all  other
       specifications  in  the same set.  This is useful for defining multiple
       sets of options which are mutually exclusive and in which  the  options
       are aliases for each other.  For example:

              _arguments \
                  -a -b \
                -(compress)\
                  {-c,--compress}[compress]\
                -(uncompress)\
                  {-d,--decompress}[decompress]’

       As  the  completion  code  has to parse the command line separately for
       each set this form of argument is slow and should  only  be  used  when
       necessary.   A useful alternative is often an option specification with
       rest-arguments (as in ‘-foo:*:...’); here the option -foo  swallows  up
       all remaining arguments as described by the optarg definitions.

       The  options -S and -A are available to simplify the specifications for
       commands with standard option parsing.  With  -S,  no  option  will  be
       completed  after a ‘--’ appearing on its own on the line; this argument
       will otherwise be ignored; hence in the line

              foobar -a -- -b

       the ‘-a’ is  considered  an  option  but  the  ‘-b’  is  considered  an
       argument, while the ‘--’ is considered to be neither.

       With  -A,  no  options  will  be  completed  after the first non-option
       argument on the line.  The -A must be followed by  a  pattern  matching
       all  strings  which  are not to be taken as arguments.  For example, to
       make  _arguments  stop  completing  options  after  the  first   normal
       argument,  but ignoring all strings starting with a hyphen even if they
       are not described by one of the optspecs, the form is ‘-A "-*"’.

       The option ‘-O name’ specifies the name of an array whose elements will
       be  passed  as  arguments  to functions called to execute actions.  For
       example, this can be used to pass the  same  set  of  options  for  the
       compadd builtin to all actions.

       The  option  ‘-M  spec’ sets a match specification to use to completion
       option names and values.  It must  appear  before  the  first  argument
       specification.   The  default is ‘r:|[_-]=* r:|=*’: this allows partial
       word completion after ‘_’ and ‘-’, for example ‘-f-b’ can be  completed
       to ‘-foo-bar’.

       The  option  -C tells _arguments to modify the curcontext parameter for
       an action of the form ‘->state’.  This is the standard  parameter  used
       to  keep  track  of  the current context.  Here it (and not the context
       array) should be made local to the calling function  to  avoid  passing
       back  the modified value and should be initialised to the current value
       at the start of the function:

              local curcontext="$curcontext"

       This is useful where it is not possible for multiple states to be valid
       together.

       The option ‘--’ allows _arguments to work out the names of long options
       that support  the  ‘--help’  option  which  is  standard  in  many  GNU
       commands.   The  command  word is called with the argument ‘--help’ and
       the output examined for option names.  Clearly, it can be dangerous  to
       pass  this  to  commands  which  may  not  support  this  option as the
       behaviour of the command is unspecified.

       In addition to options, ‘_arguments --’ will try to deduce the types of
       arguments available for options when the form ‘--opt=val’ is valid.  It
       is also possible to provide hints by examining the  help  text  of  the
       command  and  adding  specifiers  of the form ‘pattern:message:action’;
       note that normal _arguments specifiers are not used.   The  pattern  is
       matched  against  the  help  text  for an option, and if it matches the
       message and action are used as  for  other  argument  specifiers.   For
       example:

              _arguments --*\*:toggle:(yes no)\*=FILE*:file:_files\*=DIR*:directory:_files -/\*=PATH*:directory:_files -/’

       Here, ‘yes’ and ‘no’ will be completed as the argument of options whose
       description ends in a star; file names will be  completed  for  options
       that  contain the substring ‘=FILE’ in the description; and directories
       will be completed for options  whose  description  contains  ‘=DIR’  or
       ‘=PATH’.   The  last  three  are in fact the default and so need not be
       given explicitly, although it is possible to override the use of  these
       patterns.  A typical help text which uses this feature is:

                -C, --directory=DIR          change to directory DIR

       so that the above specifications will cause directories to be completed
       after ‘--directory’, though not after ‘-C’.

       Note also that _arguments  tries  to  find  out  automatically  if  the
       argument  for  an option is optional.  This can be specified explicitly
       by doubling the colon before the message.

       If the pattern ends in ‘(-)’, this will removed from  the  pattern  and
       the  action  will  be used only directly after the ‘=’, not in the next
       word.  This is the behaviour of a normal specification defined with the
       form ‘=-’.

       The ‘_arguments --’ can be followed by the option ‘-i patterns’ to give
       patterns for options which are not to be completed.  The  patterns  can
       be  given  as  the  name  of an array parameter or as a literal list in
       parentheses.  For example,

              _arguments -- -i \
                  "(--(en|dis)able-FEATURE*)"

       will cause completion to  ignore  the  options  ‘--enable-FEATURE’  and
       ‘--disable-FEATURE’ (this example is useful with GNU configure).

       The  ‘_arguments  --’ form can also be followed by the option ‘-s pair’
       to describe option aliases.  Each pair consists  of  a  pattern  and  a
       replacement.  For example, some configure-scripts describe options only
       as  ‘--enable-foo’,  but  also  accept   ‘--disable-foo’.    To   allow
       completion of the second form:

              _arguments -- -s "(#--enable- --disable-)"

       Here is a more general example of the use of _arguments:

              _arguments-l+:left border:\-format:paper size:(letter A4)\*-copy:output file:_files::resolution:(300 600)\:postscript file:_files -g \*.\(ps\|eps\)\*:page number:’

       This  describes three options: ‘-l’, ‘-format’, and ‘-copy’.  The first
       takes one argument described as ‘left border’ for which  no  completion
       will  be  offered  because  of the empty action.  Its argument may come
       directly after the ‘-l’ or it may be given as  the  next  word  on  the
       line.

       The  ‘-format’ option takes one argument in the next word, described as
       ‘paper size’ for which only the  strings  ‘letter’  and  ‘A4’  will  be
       completed.

       The  ‘-copy’  option  may appear more than once on the command line and
       takes two arguments.  The first is mandatory and will be completed as a
       filename.   The  second is optional (because of the second colon before
       the description ‘resolution’) and will be completed  from  the  strings
       ‘300’ and ‘600’.

       The  last  two  descriptions say what should be completed as arguments.
       The first describes the first argument as a ‘postscript file’ and makes
       files ending in ‘ps’ or ‘eps’ be completed.  The last description gives
       all other arguments the description ‘page numbers’ but does  not  offer
       completions.

       _cache_invalid cache_identifier
              This  function  returns  status  zero  if  the completions cache
              corresponding to the given cache  identifier  needs  rebuilding.
              It  determines this by looking up the cache-policy style for the
              current context.  This should provide a function name  which  is
              run  with  the  full path to the relevant cache file as the only
              argument.

              Example:

                     _example_caching_policy () {
                         # rebuild if cache is more than a week old
                         oldp=( "$1"(Nmw+1) )
                         (( $#oldp ))
                     }

       _call_function return name [ args ... ]
              If a function name exists, it is called with the arguments args.
              The  return  argument gives the name of a parameter in which the
              return status from the function name; if return is  empty  or  a
              single hyphen it is ignored.

              The  return  status  of  _call_function  itself  is  zero if the
              function name exists and was called and non-zero otherwise.

       _call_program tag string ...
              This function provides a mechanism for the user to override  the
              use  of an external command.  It looks up the command style with
              the supplied tag.  If the style is set, its value is used as the
              command to execute.  The strings from the call to _call_program,
              or from the style if set, are concatenated with  spaces  between
              them  and  the resulting string is evaluated.  The return status
              is the return status of the command called.

       _combination [ -s pattern ] tag style spec ... field opts ...
              This function is used to complete combinations of  values,   for
              example  pairs  of  hostnames and usernames.  The style argument
              gives the style which defines the pairs; it is looked  up  in  a
              context with the tag specified.

              The style name consists of field names separated by hyphens, for
              example ‘users-hosts-ports’.  For each  field  for  a  value  is
              already known, a spec of the form ‘field=pattern’ is given.  For
              example, if the command line so far specifies a user ‘pws’,  the
              argument ‘users=pws’ should appear.

              The  next  argument  with no equals sign is taken as the name of
              the field for which completions should be generated  (presumably
              not one of the fields for which the value is known).

              The matches generated will be taken from the value of the style.
              These should contain the possible values for the combinations in
              the  appropriate  order  (users,  hosts,  ports  in  the example
              above).  The different  fields  the  values  for  the  different
              fields  are  separated  by colons.  This can be altered with the
              option -s to _combination which specifies a pattern.   Typically
              this  is  a  character  class, as for example ‘-s "[:@]"’ in the
              case  of  the   users-hosts   style.      Each   ‘field=pattern’
              specification  restricts the completions which apply to elements
              of the style with appropriately matching fields.

              If no style with the given name is defined for the given tag, or
              if  none  of  the strings in style’s value match, but a function
              name of the required field preceded by an underscore is defined,
              that  function  will  be  called  to  generate the matches.  For
              example, if there  is  no  ‘users-hosts-ports’  or  no  matching
              hostname  when  a  host  is required, the function ‘_hosts’ will
              automatically be called.

              If the same name is used for more than one field,  in  both  the
              ‘field=pattern’  and  the  argument  that  gives the name of the
              field to be completed, the number of the  field  (starting  with
              one)  may  be  given after the fieldname, separated from it by a
              colon.

              All arguments after  the  required  field  name  are  passed  to
              compadd  when generating matches from the style value, or to the
              functions for the fields if they are called.

       _describe [ -oO | -t tag ] descr name1 [ name2 ] opts ... -- ...
              This  function   associates   completions   with   descriptions.
              Multiple  groups  separated  by  -- can be supplied, potentially
              with different completion options opts.

              The descr is taken as a string to display above the  matches  if
              the  format  style  for  the  descriptions  tag is set.  This is
              followed by one or two names of arrays followed  by  options  to
              pass   to  compadd.   The  first  array  contains  the  possible
              completions   with    their    descriptions    in    the    form
              ‘completion:description’.  If a second array is given, it should
              have the same number of elements as the first; in this case  the
              corresponding elements are added as possible completions instead
              of the completion strings from the first array.  The  completion
              list   will  retain  the  descriptions  from  the  first  array.
              Finally, a set of completion options can appear.

              If the option  ‘-o’  appears  before  the  first  argument,  the
              matches  added will be treated as names of command options (N.B.
              not shell options), typically following a ‘-’, ‘--’  or  ‘+’  on
              the   command   line.    In   this   case   _describe  uses  the
              prefix-hidden, prefix-needed and verbose styles to find  out  if
              the   strings   should  be  added  as  completions  and  if  the
              descriptions should be shown.  Without the ‘-o’ option, only the
              verbose  style is used to decide how descriptions are shown.  If
              ‘-O’ is used instead of ‘-O’, command options are  completed  as
              above but _describe will not handle the prefix-needed style.

              With  the  -t  option  a  tag  can be specified.  The default is
              ‘values’ or, if the -o option is given, ‘options’.

              If selected by the list-grouped style,  strings  with  the  same
              description will appear together in the list.

              _describe uses the _all_labels function to generate the matches,
              so it does not need to appear inside a loop over tag labels.

       _description [ -x ] [ -12VJ ] tag name descr [ spec ... ]
              This function is not to be confused with the previous one; it is
              used  as  a helper function for creating options to compadd.  It
              is buried inside many of the higher level  completion  functions
              and so often does not need to be called directly.

              The  styles listed below are tested in the current context using
              the given tag.  The resulting options for compadd are  put  into
              the  array  named  name  (this is traditionally ‘expl’, but this
              convention  is  not  enforced).    The   description   for   the
              corresponding set of matches is passed to the function in descr.

              The styles tested are: format, hidden, matcher, ignored-patterns
              and  group-name.  The format style is first tested for the given
              tag and then for the descriptions tag if  no  value  was  found,
              while  the  remainder  are  only tested for the tag given as the
              first argument.  The function also calls _setup which tests some
              more styles.

              The  string  returned  by  the  format  style  (if  any) will be
              modified so that the sequence ‘%d’  is  replaced  by  the  descr
              given  as  the  third  argument  without any leading or trailing
              white space.  If, after removing the white space, the  descr  is
              the  empty  string,  the  format  style will not be used and the
              options put into the name array will not contain an  explanation
              string to be displayed above the matches.

              If  _description  is  called with more than three arguments, the
              additional specs should be of the form ‘char:str’.  These supply
              escape   sequence  replacements  for  the  format  style:  every
              appearance of ‘%char’ will be replaced by string.

              If the -x option is given, the description  will  be  passed  to
              compadd  using  the  -x  option instead of the default -X.  This
              means that the description will be displayed even if  there  are
              no corresponding matches.

              The  options  placed  in  the  array  name  take  account of the
              group-name style, so matches are  placed  in  a  separate  group
              where necessary.  The group normally has its elements sorted (by
              passing the option -J to compadd), but  if  an  option  starting
              with  ‘-V’,  ‘-J’, ‘-1’, or ‘-2’ is passed to _description, that
              option will be included in the array.  Hence it is possible  for
              the  completion  group to be unsorted by giving the option ‘-V’,
              ‘-1V’, or ‘-2V’.

              In most cases, the function will be used like this:

                     local expl
                     _description files expl file
                     compadd "$expl[@]" - "$files[@]"

              Note the use of the parameter expl, the hyphen, and the list  of
              matches.   Almost  all  calls  to  compadd within the completion
              system use a similar format; this  ensures  that  user-specified
              styles are correctly passed down to the builtins which implement
              the internals of completion.

       _dispatch context string ...
              This  sets  the  current  context  to  context  and  looks   for
              completion  functions  to handle this context by hunting through
              the list of command names  or  special  contexts  (as  described
              above  for  compdef)  given as string ....  The first completion
              function to be defined for one of the contexts in  the  list  is
              used  to  generate  matches.   Typically,  the  last  string  is
              -default- to cause the function for  default  completion  to  be
              used as a fallback.

              The  function  sets  the  parameter $service to the string being
              tried, and sets the context/command field (the  fourth)  of  the
              $curcontext   parameter  to  the  context  given  as  the  first
              argument.

       _files The function _files calls _path_files with all the arguments  it
              was  passed  except for -g and -/.  The use of these two options
              depends on the setting of the  file-patterns style.

              This function  accepts  the  full  set  of  options  allowed  by
              _path_files, described below.

       _gnu_generic
              This function is a simple wrapper around the _arguments function
              described above.  It can be used to determine automatically  the
              long  options  understood  by  commands that produce a list when
              passed the option ‘--help’.  It is intended  to  be  used  as  a
              top-level completion function in its own right.  For example, to
              enable option completion for the commands foo and bar, use

                     compdef _gnu_generic foo bar

              after the call to compinit.

              The completion system as supplied is conservative in its use  of
              this  function,  since  it  is  important to be sure the command
              understands the option ‘--help’.

       _guard [ options ] pattern descr
              This function is intended to be  used  in  the  action  for  the
              specifications  passed  to _arguments and similar functions.  It
              returns immediately with a non-zero return status if the  string
              to  be  completed  does  not  match the pattern.  If the pattern
              matches, the descr  is  displayed;  the  function  then  returns
              status  zero  if  the  word  to  complete is not empty, non-zero
              otherwise.

              The pattern may be preceded by any of the options understood  by
              compadd  that  are passed down from _description, namely -M, -J,
              -V, -1, -2, -n, -F  and  -X.   All  of  these  options  will  be
              ignored.   This  fits  in conveniently with the argument-passing
              conventions of actions for _arguments.

              As an example, consider a command  taking  the  options  -n  and
              -none,  where -n must be followed by a numeric value in the same
              word.  By using:

                     _arguments-n-: :_guard "[0-9]#" "numeric value"’ ’-none_arguments can be made to  both  display  the  message  ‘numeric
              value’  and  complete  options  after ‘-n<TAB>’.  If the ‘-n’ is
              already followed by one or more digits (the  pattern  passed  to
              _guard)  only  the  message  will  be  displayed; if the ‘-n’ is
              followed by another character, only options are completed.

       _message [ -r12 ] [ -VJ group ] descr
       _message -e [ tag ] descr
              The descr is used in the same way as the third argument  to  the
              _description  function,  except  that  the resulting string will
              always be shown whether or not matches were generated.  This  is
              useful  for  displaying  a  help  message  in  places  where  no
              completions can be generated.

              The format style is examined with the messages  tag  to  find  a
              message;  the usual tag, descriptions, is used only if the style
              is not set with the former.

              If the -r option is given, no style is used; the descr is  taken
              literally  as  the  string to display.  This is most useful when
              the descr comes from a pre-processed argument list which already
              contains an expanded description.

              The  -12VJ options and the group are passed to compadd and hence
              determine the group the message string is added to.

              The second form gives a description for completions with the tag
              tag  to be shown even if there are no matches for that tag.  The
              tag can be omitted and if so the tag is taken from the parameter
              $curtag;  this  is maintained by the completion system and so is
              usually correct.

       _multi_parts sep array
              The argument sep is a separator character.   The  array  may  be
              either  the name of an array parameter or a literal array in the
              form ‘(foo bar)’, a parenthesised list  of  words  separated  by
              whitespace.   The  possible completions are the strings from the
              array.  However, each chunk delimited by sep will  be  completed
              separately.  For example, the _tar function uses ‘_multi_parts /
              patharray’ to complete partial file paths from the  given  array
              of complete file paths.

              The  -i option causes _multi_parts to insert a unique match even
              if that requires multiple separators to be  inserted.   This  is
              not  usually  the expected behaviour with filenames, but certain
              other types of completion, for example those with a fixed set of
              possibilities, may be more suited to this form.

              Like  other  utility  functions, this function accepts the ‘-V’,
              ‘-J’, ‘-1’, ‘-2’, ‘-n’, ‘-f’,  ‘-X’,  ‘-M’,  ‘-P’,  ‘-S’,  ‘-r’,
              ‘-R’, and ‘-q’ options and passes them to the compadd builtin.

       _next_label [ -x ] [ -12VJ ] tag name descr [ options ... ]
              This  function  is used to implement the loop over different tag
              labels for a particular tag as described above for the tag-order
              style.   On each call it checks to see if there are any more tag
              labels; if there is it returns status zero, otherwise  non-zero.
              As  this  function  requires  a  current  tag to be set, it must
              always follow a call to _tags or _requested.

              The -x12VJ options and the first three arguments are  passed  to
              the  _description  function.   Where appropriate the tag will be
              replaced by a tag label in this call.  Any description given  in
              the  tag-order  style  is  preferred  to  the  descr  passed  to
              _next_label.

              The options given after the descr are set in the parameter given
              by  name,  and  hence  are  to  be passed to compadd or whatever
              function is called to add the matches.

              Here is a typical use of this function for  the  tag  foo.   The
              call to _requested determines if tag foo is required at all; the
              loop over _next_label handles any labels defined for the tag  in
              the tag-order style.

                     local expl ret=1
                     ...
                     if _requested foo; then
                       ...
                       while _next_label foo expl...; do
                         compadd "$expl[@]" ... && ret=0
                       done
                       ...
                     fi
                     return ret

       _normal
              This  is  the  standard  function  called  to  handle completion
              outside any special -context-.  It is called  both  to  complete
              the  command  word and also the arguments for a command.  In the
              second case, _normal looks for a  special  completion  for  that
              command,  and  if  there  is none it uses the completion for the
              -default- context.

              A second use is to reexamine the command line specified  by  the
              $words  array  and  the $CURRENT parameter after those have been
              modified.   For  example,  the   function   _precommand,   which
              completes  after  pre-command  specifiers such as nohup, removes
              the first word from the  words  array,  decrements  the  CURRENT
              parameter,  then calls _normal again.  The effect is that ‘nohup
              cmd ...’ is treated in the same way as ‘cmd ...’.

              If the command name matches one of the patterns given by one  of
              the  options  -p  or -P to compdef, the corresponding completion
              function is called and then the parameter _compskip is  checked.
              If  it  is set completion is terminated at that point even if no
              matches have been found.  This is the  same  effect  as  in  the
              -first- context.

       _options
              This  can  be  used  to complete the names of shell options.  It
              provides a matcher specification that ignores  a  leading  ‘no’,
              ignores underscores and allows upper-case letters to match their
              lower-case  counterparts   (for   example,   ‘glob’,   ‘noglob’,
              ‘NO_GLOB’  are  all completed).  Any arguments are propagated to
              the compadd builtin.

       _options_set and _options_unset
              These functions complete only set or  unset  options,  with  the
              same matching specification used in the _options function.

              Note   that   you   need   to  uncomment  a  few  lines  in  the
              _main_complete function for these functions  to  work  properly.
              The  lines  in question are used to store the option settings in
              effect before the completion widget locally sets the options  it
              needs.   Hence  these  functions  are  not generally used by the
              completion system.

       _parameters
              This is used to complete the names of shell parameters.

              The option ‘-g pattern  limits  the  completion  to  parameters
              whose type matches the pattern.  The type of a parameter is that
              shown by print ${(t)param}, hence  judicious  use  of  *  in
              pattern is probably necessary.

              All other arguments are passed to the compadd builtin.

       _path_files
              This  function  is  used  throughout  the  completion  system to
              complete filenames.  It allows completion of partial paths.  For
              example,   the   string   ‘/u/i/s/sig’   may   be  completed  to
              ‘/usr/include/sys/signal.h’.

              The options accepted by both _path_files and _files are:

              -f     Complete all filenames.  This is the default.

              -/     Specifies that only directories should be completed.

              -g pattern
                     Specifies that only files matching the pattern should  be
                     completed.

              -W paths
                     Specifies  path  prefixes that are to be prepended to the
                     string from the command line to  generate  the  filenames
                     but  that should not be inserted as completions nor shown
                     in completion listings.  Here, paths may be the  name  of
                     an  array  parameter, a literal list of paths enclosed in
                     parentheses or an absolute pathname.

              -F ignored-files
                     This behaves as  for  the  corresponding  option  to  the
                     compadd  builtin.   It  gives  direct  control over which
                     filenames should  be  ignored.   If  the  option  is  not
                     present, the ignored-patterns style is used.

              Both  _path_files  and  _files also accept the following options
              which are passed to compadd: ‘-J’, ‘-V’, ‘-1’, ‘-2’, ‘-n’, ‘-X’,
              ‘-M’, ‘-P’, ‘-S’, ‘-q’, ‘-r’, and ‘-R’.

              Finally,  the  _path_files  function   uses  the  styles expand,
              ambiguous, special-dirs, list-suffixes and  file-sort  described
              above.

       _pick_variant [ -c command ] [ -r name ] label=pattern ... label [ args
       ... ]
              This  function  is  used  to  resolve  situations where a single
              command name requires more than one  type  of  handling,  either
              because  it has more than one variant or because there is a name
              clash between two different commands.

              The command to run is taken from the first element of the  array
              words  unless this is overridden by the option -c.  This command
              is run and its output is compared with  a  series  of  patterns.
              Arguments  to  be  passed to the command can be specified at the
              end after all the other arguments.  The patterns to try in order
              are  given  by  the  arguments  label=pattern;  if the output of
              ‘command args ...’ contains pattern, then label is  selected  as
              the  label  for  the  command  variant.  If none of the patterns
              match, the final command label  is  selected  and  status  1  is
              returned.

              If  the  ‘-r  name’  is given, the label picked is stored in the
              parameter named name.

              The results are also  cached  in  the  _cmd_variant  associative
              array indexed by the name of the command run.

       _regex_arguments name spec ...
              This function generates a completion function name which matches
              the specifications spec ..., a set  of  regular  expressions  as
              described  below.   After running _regex_arguments, the function
              name should be called as  a  normal  completion  function.   The
              pattern  to  be  matched  is  given by the contents of the words
              array up to the current cursor  position  joined  together  with
              null characters; no quotation is applied.

              The  arguments  are grouped as sets of alternatives separated by
              ‘|’, which are tried one after  the  other  until  one  matches.
              Each  alternative consists of a one or more specifications which
              are tried  left  to  right,  with  each  pattern  matched  being
              stripped  in  turn from the command line being tested, until all
              of the group succeeds or until one fails; in  the  latter  case,
              the  next  alternative is tried.  This structure can be repeated
              to arbitrary depth by using parentheses; matching proceeds  from
              inside to outside.

              A  special  procedure  is  applied  if  no test succeeds but the
              remaining  command  line  string  contains  no  null   character
              (implying  the  remaining  word is the one for which completions
              are to be generated).  The completion target  is  restricted  to
              the  remaining  word  and  any  actions  for  the  corresponding
              patterns are executed.  In this case, nothing is  stripped  from
              the command line string.  The order of evaluation of the actions
              can be determined by the tag-order style;  the  various  formats
              supported  by  _alternative can be used in action.  The descr is
              used for setting up the array parameter expl.

              Specification arguments take one of following  forms,  in  which
              metacharacters such as ‘(’, ‘)’, ‘#’ and ‘|’ should be quoted.

              /pattern/ [%lookahead%] [-guard] [:tag:descr:action]
                     This is a single primitive component.  The function tests
                     whether          the           combined           pattern
                     ‘(#b)((#B)pattern)lookahead*’  matches  the  command line
                     string.  If so,  ‘guard’  is  evaluated  and  its  return
                     status   is   examined  to  determine  if  the  test  has
                     succeeded.  The pattern string ‘[]’ is  guaranteed  never
                     to match.  The lookahead is not stripped from the command
                     line before the next pattern is examined.

                     The argument starting with : is used in the  same  manner
                     as an argument to _alternative.

                     A  component is used as follows: pattern is tested to see
                     if the component already exists on the command line.   If
                     it  does,  any  following  specifications are examined to
                     find something to complete.  If a  component  is  reached
                     but  no  such pattern exists yet on the command line, the
                     string containing the action is used to generate  matches
                     to insert at that point.

              /pattern/+ [%lookahead%] [-guard] [:tag:descr:action]
                     This  is  similar to ‘/pattern/ ...’ but the left part of
                     the command line string (i.e. the part already matched by
                     previous   patterns)  is  also  considered  part  of  the
                     completion target.

              /pattern/- [%lookahead%] [-guard] [:tag:descr:action]
                     This is similar to ‘/pattern/ ...’ but the actions of the
                     current  and previously matched patterns are ignored even
                     if the following ‘pattern’ matches the empty string.

              ( spec )
                     Parentheses may  be  used  to  groups  specs;  note  each
                     parenthesis is a single argument to _regex_arguments.

              spec # This allows any number of repetitions of spec.

              spec spec
                     The  two  specs  are to be matched one after the other as
                     described above.

              spec | spec
                     Either of the two specs can be matched.

              The function _regex_words can be used as a  helper  function  to
              generate  matches  for  a set of alternative words possibly with
              their own arguments as a command line argument.

              Examples:

                     _regex_arguments _tst /$[^\0]#\0/ \
                     /$[^\0]#\0/ :compadd aaa’

              This generates a function _tst that completes aaa  as  its  only
              argument.   The  tag  and  description  for the action have been
              omitted for brevity (this works but is not recommended in normal
              use).   The  first  component matches the command word, which is
              arbitrary; the second matches  any argument.  As the argument is
              also  arbitrary, any following component would not depend on aaa
              being present.

                     _regex_arguments _tst /$[^\0]#\0/ \
                     /$aaa\0/ :compadd aaa’

              This is a more typical use; it is  similar,  but  any  following
              patterns  would  only  match  if  aaa  was  present as the first
              argument.

                     _regex_arguments _tst /$[^\0]#\0/ \( \
                     /$aaa\0/ :compadd aaa\
                     /$bbb\0/ :compadd bbb\) \#

              In this example, an indefinite number of command  arguments  may
              be  completed.   Odd  arguments  are  completed  as aaa and even
              arguments as bbb.  Completion fails unless the set  of  aaa  and
              bbb arguments before the current one is matched correctly.

                     _regex_arguments _tst /$[^\0]#\0/ \
                     \( /$aaa\0/ :compadd aaa\| \
                     /$bbb\0/ :compadd bbb\) \#

              This  is similar, but either aaa or bbb may be completed for any
              argument.  In this case _regex_words could be used to generate a
              suitable expression for the arguments.

       _regex_words tag description spec ...
              This  function  can  be  used  to  generate  arguments  for  the
              _regex_arguments command which may  be  inserted  at  any  point
              where  a set of rules is expected.  The tag and description give
              a  standard  tag  and  description  pertaining  to  the  current
              context.  Each spec contains two or three arguments separated by
              a colon: note that there is no leading colon in this case.

              Each spec gives one of a set of words that may be  completed  at
              this  point,  together  with  arguments.   It  is  thus  roughly
              equivalent to  the  _arguments  function  when  used  in  normal
              (non-regex) completion.

              The  part  of  the spec before the first colon is the word to be
              completed.  This may contain a *; the entire  word,  before  and
              after  the  *  is  completed,  but only the text before the * is
              required  for  the  context  to  be  matched,  so  that  further
              arguments may be completed after the abbreviated form.

              The  second  part  of  spec  is a description for the word being
              completed.

              The  optional  third  part  of  the  spec  describes  how  words
              following   the   one  being  completed  are  themselves  to  be
              completed.  It will be evaluated in order to avoid problems with
              quoting.   This  means that typically it contains a reference to
              an array containing previously generated regex arguments.

              The option -t term specifies a terminator for the  word  instead
              of the usual space.  This is handled as an auto-removable suffix
              in the manner of the option -s sep to _values.

              The result of the processing by _regex_words is  placed  in  the
              array reply, which should be made local to the calling function.
              If the set of words and arguments may be matched repeatedly, a #
              should be appended to the generated array at that point.

              For example:

                     local -a reply
                     _regex_words mydb-commandsmydb commands\add:add an entry to mydb:$mydb_add_cmds\show:show entries in mydb_regex_arguments _mydb "$reply[@]"
                     _mydb "$@"

              This  shows a completion function for a command mydb which takes
              two command arguments, add and show.  show takes  no  arguments,
              while  the  arguments  for  add have already been prepared in an
              array mydb_add_cmds,  quite  possibly  by  a  previous  call  to
              _regex_words.

       _requested [ -x ] [ -12VJ ] tag [ name descr [ command args ... ] ]
              This  function  is  called  to  decide  whether  a  tag  already
              registered by a call to _tags (see below) has been requested  by
              the  user  and  hence completion should be performed for it.  It
              returns status  zero  if  the  tag  is  requested  and  non-zero
              otherwise.   The  function  is  typically used as part of a loop
              over different tags as follows:

                     _tags foo bar baz
                     while _tags; do
                       if _requested foo; then
                         ... # perform completion for foo
                       fi
                       ... # test the tags bar and baz in the same way
                       ... # exit loop if matches were generated
                     done

              Note that the test for whether matches  were  generated  is  not
              performed  until the end of the _tags loop.  This is so that the
              user can set the tag-order style to specify a set of tags to  be
              completed at the same time.

              If  name  and descr are given, _requested calls the _description
              function with these arguments together with the  options  passed
              to _requested.

              If  command  is  given,  the _all_labels function will be called
              immediately with the same arguments.  In simple cases this makes
              it  possible to perform the test for the tag and the matching in
              one go.  For example:

                     local expl ret=1
                     _tags foo bar baz
                     while _tags; do
                       _requested foo expldescription\
                           compadd foobar foobaz && ret=0
                       ...
                       (( ret )) || break
                     done

              If the command is not compadd, it must nevertheless be  prepared
              to handle the same options.

       _retrieve_cache cache_identifier
              This  function  retrieves  completion  information from the file
              given by cache_identifier, stored in a  directory  specified  by
              the  cache-path  style  which  defaults  to  ~/.zcompcache.  The
              return status is zero if retrieval was successful.  It will only
              attempt retrieval if the use-cache style is set, so you can call
              this function without worrying about whether the user wanted  to
              use the caching layer.

              See _store_cache below for more details.

       _sep_parts
              This  function  is  passed  alternating arrays and separators as
              arguments.  The arrays specify completions for parts of  strings
              to  be separated by the separators.  The arrays may be the names
              of array parameters or a quoted list of  words  in  parentheses.
              For   example,  with  the  array  ‘hosts=(ftp  news)’  the  call
              ‘_sep_parts(foo bar)@ hosts’ will complete the  string   ‘f’
              to ‘foo’ and the string ‘b@n’ to ‘bar@news’.

              This  function  accepts  the  compadd  options ‘-V’, ‘-J’, ‘-1’,
              ‘-2’, ‘-n’, ‘-X’, ‘-M’, ‘-P’, ‘-S’, ‘-r’,  ‘-R’,  and  ‘-q’  and
              passes them on to the compadd builtin used to add the matches.

       _setup tag [ group ]
              This  function  sets  up  the  special  parameters  used  by the
              completion system appropriately for the tag given as  the  first
              argument.    It   uses   the  styles  list-colors,  list-packed,
              list-rows-first, last-prompt, accept-exact, menu and force-list.

              The  optional  group supplies the name of the group in which the
              matches will be placed.  If it is not given, the tag is used  as
              the group name.

              This  function  is  called  automatically  from _description and
              hence is not normally called explicitly.

       _store_cache cache_identifier params ...
              This function, together with _retrieve_cache and _cache_invalid,
              implements  a  caching layer which can be used in any completion
              function.  Data obtained by  costly  operations  are  stored  in
              parameters;  this  function  then  dumps  the  values  of  those
              parameters to a file.  The data can then  be  retrieved  quickly
              from  that file via _retrieve_cache, even in different instances
              of the shell.

              The cache_identifier specifies the file which the data should be
              dumped  to.   The file is stored in a directory specified by the
              cache-path style which defaults to ~/.zcompcache.  The remaining
              params arguments are the parameters to dump to the file.

              The  return  status  is  zero  if  storage  was successful.  The
              function will only attempt storage if  the  use-cache  style  is
              set,  so  you  can  call  this  function  without worrying about
              whether the user wanted to use the caching layer.

              The completion function may avoid calling  _retrieve_cache  when
              it  already  has  the  completion  data available as parameters.
              However, in that case it should  call  _cache_invalid  to  check
              whether  the  data  in the parameters and in the cache are still
              valid.

              See the _perl_modules completion function for a  simple  example
              of the usage of the caching layer.

       _tags [ [ -C name ] tags ... ]
              If  called  with  arguments,  these are taken to be the names of
              tags valid for completions in the current context.   These  tags
              are stored internally and sorted by using the tag-order style.

              Next, _tags is called repeatedly without arguments from the same
              completion  function.   This  successively  selects  the  first,
              second,  etc.  set  of  tags  requested by the user.  The return
              status is zero if at least one of  the  tags  is  requested  and
              non-zero otherwise.  To test if a particular tag is to be tried,
              the _requested function should be called (see above).

              If ‘-C name’  is  given,  name  is  temporarily  stored  in  the
              argument  field  (the  fifth)  of  the context in the curcontext
              parameter during the call to _tags; the  field  is  restored  on
              exit.   This allows _tags to use a more specific context without
              having to change and reset the curcontext parameter  (which  has
              the same effect).

       _values [ -O name ] [ -s sep ] [ -S sep ] [ -wC ] desc spec ...
              This  is  used to complete arbitrary keywords (values) and their
              arguments, or lists of such combinations.

              If the first argument is the option ‘-O name’, it will  be  used
              in  the same way as by the _arguments function.  In other words,
              the elements of the name array will be passed  to  compadd  when
              executing an action.

              If the first argument (or the first argument after ‘-O name’) is
              ‘-s’, the next argument is used as the character that  separates
              multiple  values.   This  character is automatically added after
              each value in an auto-removable fashion (see below); all  values
              completed by ‘_values -s’ appear in the same word on the command
              line, unlike completion using _arguments.  If this option is not
              present, only a single value will be completed per word.

              Normally,  _values  will  only use the current word to determine
              which values are already present on the command line  and  hence
              are not to be completed again.  If the -w option is given, other
              arguments are examined as well.

              The first non-option argument is used as a string to print as  a
              description before listing the values.

              All  other  arguments  describe  the  possible  values and their
              arguments in the same format used for the description of options
              by  the  _arguments  function (see above).  The only differences
              are that no minus or plus sign is  required  at  the  beginning,
              values  can  have  only  one  argument,  and the forms of action
              beginning with an equal sign are not supported.

              The character separating a value from its argument  can  be  set
              using  the  option -S (like -s, followed by the character to use
              as the separator in the next argument).  By default  the  equals
              sign will be used as the separator between values and arguments.

              Example:

                     _values -s ,description\*foo[bar]\(two)*one[number]:first count:\two[another number]::second count:(1 2 3)’

              This describes three possible values: ‘foo’, ‘one’,  and  ‘two’.
              The  first  is  described  as  ‘bar’,  takes no argument and may
              appear more than once.  The second is described as ‘number’, may
              appear   more  than  once,  and  takes  one  mandatory  argument
              described as ‘first count’; no action is specified, so  it  will
              not be completed.  The ‘(two)’ at the beginning says that if the
              value ‘one’ is on the line, the value ‘two’ will  no  longer  be
              considered  a  possible  completion.   Finally,  the  last value
              (‘two’) is described as ‘another number’ and takes  an  optional
              argument  described  as ‘second count’ for which the completions
              (to appear after an ‘=’) are ‘1’, ‘2’,  and  ‘3’.   The  _values
              function  will  complete  lists  of  these  values  separated by
              commas.

              Like _arguments, this function temporarily adds another  context
              name  component  to  the  arguments  element  (the fifth) of the
              current context while executing the action.  Here this  name  is
              just  the name of the value for which the argument is completed.

              The style verbose is used to decide if the descriptions for  the
              values (but not those for the arguments) should be printed.

              The  associative  array  val_args  is  used to report values and
              their  arguments;  this  works   similarly   to   the   opt_args
              associative  array  used  by  _arguments.   Hence  the  function
              calling _values should declare the local parameters state, line,
              context and val_args:

                     local context state line
                     typeset -A val_args

              when using an action of the form ‘->string’.  With this function
              the context parameter will be set to the name of the value whose
              argument is to be completed.

              Note  also  that _values normally adds the character used as the
              separator between values as an auto-removable suffix (similar to
              a  ‘/’  after a directory).  However, this is not possible for a
              ‘->string’ action as the matches for the argument are  generated
              by  the  calling  function.  To get the usual behaviour, the the
              calling function can add the separator x as a suffix by  passing
              the options ‘-qS x’ either directly or indirectly to compadd.

              The option -C is treated in the same way as it is by _arguments.
              In that case the  parameter  curcontext  should  be  made  local
              instead of context (as described above).

       _wanted [ -x ] [ -C name ]  [ -12VJ ] tag name descr command args ...
              In  many  contexts,  completion can only generate one particular
              set of matches, usually corresponding to a single tag.  However,
              it  is  still  necessary  to  decide  whether  the user requires
              matches of this type.  This function is useful in such a case.

              The arguments to _wanted are the same as  those  to  _requested,
              i.e.  arguments  to be passed to _description.  However, in this
              case the command is not optional;  all the processing  of  tags,
              including  the  loop  over  both  tags  and  tag  labels and the
              generation of matches, is carried out automatically by  _wanted.

              Hence   to   offer   only   one  tag  and  immediately  add  the
              corresponding matches with the given description:

                     local expl
                     _wanted tag expldescription\
                         compadd matches...

              Note that, as for _requested, the command must be able to accept
              options to be passed down to compadd.

              Like  _tags  this  function  supports  the  -C  option to give a
              different name for the argument context field.   The  -x  option
              has the same meaning as for _description.

COMPLETION DIRECTORIES

       In  the  source  distribution,  the  files  are  contained  in  various
       subdirectories  of  the  Completion  directory.   They  may  have  been
       installed in the same structure, or into one single function directory.
       The following is a description of  the  files  found  in  the  original
       directory  structure.  If you wish to alter an installed file, you will
       need to copy it to some directory which appears earlier in  your  fpath
       than the standard directory where it appears.

       Base   The  core functions and special completion widgets automatically
              bound to keys.  You will certainly need most  of  these,  though
              will  probably  not  need  to  alter  them.   Many  of these are
              documented above.

       Zsh    Functions for completing arguments of shell builtin commands and
              utility  functions  for  this.   Some  of these are also used by
              functions from the Unix directory.

       Unix   Functions for completing  arguments  of  external  commands  and
              suites  of  commands.   They may need modifying for your system,
              although in many cases some attempt  is  made  to  decide  which
              version  of  a  command is present.  For example, completion for
              the mount command tries to determine the system  it  is  running
              on,  while  completion  for  many  other utilities try to decide
              whether the GNU version of the command  is  in  use,  and  hence
              whether the --help option is supported.

       X, AIX, BSD, ...
              Completion  and  utility function for commands available only on
              some systems.  These are not arranged  hierarchically,  so,  for
              example, both the Linux and Debian directories, as well as the X
              directory, may be useful on your system.