Provided by: liblopsub-dev_1.0.3-2_amd64 bug


       lopsub-suite - lopsub suite syntax


       A  lopsub  suite describes the options to a command line utility with zero or more related
       subcommands. The lopsubgen(1) utility translates a lopsub suite into either C source  code
       or  a  manual  page.  The  generated  C code can be compiled and linked against the lopsub
       library to produce command line parsers for the main command and all  subcommands  defined
       in the suite.

       This document explains the format of a lopsub suite. The overall structure is as follows:

            [suite mysuite]
            suite directives

            [supercommand sup_cmd]
                 command directives for sup_cmd
                 [option opt1]
                 ... (further options)

            [subcommand sub1]
                 command directives for sub1
                 [option opt_1_to_sub1]
                      option directives for opt_1
                 ... (further options)

            ... (further subcommands)

            [section see also]
            ... (optional extra section for man page)

            ... (further extra sections)

       A  suite  begins  with  a  [suite]  line  which  declares the name of the suite. The suite
       directives, all subsequent lines up to the  first  [supercommand]  or  [subcommand]  line,
       state  further  properties of the suite which are unrelated to any particular command, for
       example the version number. All available suite directives are summarized below.

       The [supercommand] and [subcommand] lines indicate the  beginning  of  a  command  of  the
       suite.  The  part  between  this  line  and  the  first [option] line contains the command
       directives, for example the purpose and the description of the  named  command.   See  the
       section on command directives below.

       Supercommands  and  subcommands  share  the  same set of possible command directives. They
       differ mainly in the way the documentation is formated. There can only be one supercommand
       but  arbitrary  many  subcommands.  For example, the supercommand could be the name of the
       application, and the subcommands could be "load", "save" "info" and "quit". The subcommand
       would  be passed as the first non-option argument to the supercommand, followed by options
       specific to that subcommand.

       Of course it is possible to define no subcommands at all. Conversely, one can define  only
       subcommands  but  no  supercommand. This makes sense if the commands are run by some other
       means, for example in an interactive session from a command prompt.

       Within the command section, an [option] line starts an option to the current  command.  It
       is  followed  by  option directives, which specify, for example, whether or not the option
       takes an argument. All supported option directives are listed in the corresponding section

       Further  material  for  man  output  can  be included between the [section] and [/section]
       markers.  This text will not be included in the generated .c and .h files and is thus also
       not  part  of  the  short and long help available at run time. The text is not interpreted
       except that leading whitespace is stripped from each line. Arbitrary roff  source  can  be
       included here.

       Empty lines and lines starting with a hash character (#) are ignored.


       Most   directives   of   this  section  are  only  relevant  for  man  page  output  (with
       aux_info_default being the exception), they are ignored for C output.

              The optional text for an unnumbered section heading at the beginning of the  manual

       title  Sets  the  title of the man page. Defaults to the name of the supercommand. If this
              is not given and the suite has no supercommand, the .TH macro to set the  title  of
              the man page is omitted.

              Sets  the  man  page section. Defaults to 1 (user commands). Both title and section
              are positioned at the left and right in the header line.

       date   This text is positioned in the middle of the footer line of the  man  page.  It  is
              common  to  set this to the date of the last nontrivial change that was made to the
              man page. Defaults to the current date.

              Positioned at the left in the footer line. Defaults to the empty string. The  value
              of this directive is ignored if a version string is explicitly requested by passing
              --version-string to losubgen.

              Centered in the header line. Defaults to "User commands".

              The text enclosed between [introduction] and [/introduction] is shown  between  the
              supercommand  (if  any)  and  the  subcommand  list.   Concluding remarks after the
              subcommand list may be added in the same way with [conclusion]  and  [/conclusion].
              Both  texts  will become part of the manual page, but are not not part of the short
              or long help. Like for the section directive, arbitrary roff source may be included

              This  text  is shown at the bottom of each command before the value of the aux_info
              directive. If no aux_info is specified for a command,  the  prefix  is  omitted  as
              well. If aux_info_prefix is not given, the empty string is assumed.

              This  text  is  only  used for header output.  The argument for the generated macro
              call is set to this value for all commands  for  which  no  aux_info  directive  is
              given.  If  no  aux_info_default  directive  is  given,  the value 0 is used as the
              argument for the macro.


              A single line containing the purpose of the command. This text is  printed  in  the
              short and long help, and is also included in the man page.

              Arbitrary  plain  text enclosed between [description] and [/description].  The text
              may  be  split  over  multiple  lines  and  paragraphs.  The  description  of   the
              supercommand  (if  any)  becomes the description of the manual page, which is shown
              after the command summary and before the list of options. The descriptions  of  all
              commands  are  included in the manual page and in the long help text but not in the
              short help.

              Closing remarks for the command can be added in a similar way  by  enclosing  plain
              text  between  [closing]  and  [/closing].   This text will be positioned after the
              option list.

              Custom synopsis of the command. If this is not given, the  synopsis  text  will  be
              auto-generated from the options and the value of the non-opts-name directive.

              Name of the command line arguments which are not related to any option, for example
              file names. This text will be included  in  the  automatically  generated  synopsis

              If  this  is  not given, the command is assumed to take no arguments other than the
              specified options and their arguments. For such commands the attempt  to  parse  an
              argv[] vector fails if it contains further non-option arguments.

              This  directive  is  special  because its value is not included in the generated .c
              file  but  in  the  header   file.   More   precisely,   the   preprocessor   macro
              LSG_SUITENAME_AUX_INFOS will be defined which expands to a series of macro calls to
              LSG_SUITENAME_AUX_INFO(val_n), one for each command of the suite,  where  val_n  is
              the  (unquoted)  value  of  the aux_info directive of the nth command. Commands for
              which  no  aux_info  directive  was  specified  receive  a  value  of   zero.   The
              LSG_SUITENAME_AUX_INFO  macro  is supposed to be defined by the application.  Hence
              it is up to the application to make  the  expansion  of  LSG_SUITENAME_AUX_INFOS  a
              valid C construct.

              The  value,  if specified, is also copied to the man page at the end of the section
              for the command.


              The optional single-letter equivalent for the option. If  this  is  specified,  the
              option  may  be  given  either in the GNU-style long option format with two leading
              dashes or in the short form with a single dash. Otherwise only the long  form  will
              be accepted. As usual, multiple short option flags may be combined.

              A  single line which summarizes the option. This text is included in both the short
              and the long help and in the man page. Defaults to the empty string.

              A description for the type of the values for the option. The given text is  printed
              in  the  synopsis  of the command, which is part of the short and the long help and
              the man page. It defaults to the string "val".

              This directive is ignored for flag options (options without an argument).

              This directive determines whether the option takes an argument. The possible values
              are  no_arg,  required_arg  and optional_arg which indicate, respectively, that the
              option takes no argument at all, an argument which is  mandatory,  or  an  argument
              which may be omitted. The default value is no_arg.  Hence an option works as a flag
              if the arg_info directive is not given.

              Note that arguments to options which take an optional argument  must  be  given  as
              --foo=bar rather than --foo bar because the latter form would be ambiguous.

              For  flag  options  this  directive  should  be set to none, or not set at all. For
              options which take an argument, the value of the directive determines the  type  of
              the argument.  Possible values are string for options which take a string argument,
              and int32, uint32.  int64, uint64, for options which take a numeric argument.

       flag   Lopsub maintains for each option  a  bitmask  which  contains  the  value  of  each
              possible  flag  for this option. Flags may be accumulated by defining multiple flag
              directives in the suite. Note there is no equal sign between the flag directive and
              its value.

              The following flags are defined.

                     This  flag instructs the lopsub library to keep track of all given arguments
                     to an option, not just one as for ordinary options. This  is  only  relevant
                     for options which take an (optional or required) argument.

                     Instruct  the  parser  to  fail  if this option is not given in the argument
                     vector. If an option may be given at the command line or in the config file,
                     this flag should be avoided because the command line argv vector will not be
                     parsed successfully if the option is only given  in  the  config  file.  The
                     recommended  way  to  deal  with this situation is to parse command line and
                     config file separately, then merge the two parse results and  check  in  the
                     application if the option is given in the merged parse result.

                     There  is  another  disadvantage  of this flag: if the parser fails due to a
                     missing option that was declared required, it is not possible to  detect  if
                     other  options  were  given.  For  example,  if the suite defines the --help
                     option, and the application is executed with this option  only,  the  parser
                     will still return a parse error.

                     This  flag  indicates  that the current option is in fact not a real option.
                     In particular, name and short_opt are both ignored. The purpose of this flag
                     is to add additional information for the help output and the man page.

       values Create an enumerable option.

              Enumerable  options  take  one  out  of  a  fixed  set of possible values which are
              predefined in the suite. Such options are always of type string. It is an error  if
              a different argument type was specified or if the option was defined to not take an

              The syntax for the array of values is

                   values = {ID_0 = "string_0", ..., ID_N = "string_N"}

              For each option for which the values directive was specified, the lopsubgen command
              generates  a  C  enumeration  which  contains  the  given  identifiers. This allows
              referring to each possible value through a numeric constant.

              This directive makes only sense for  options  which  take  an  argument.  For  such
              options it defines the value the option parser provides automatically if the option
              is not given in the argument vector.

              If no default_val is specified in the suite, and the option is  not  given  in  the
              argument vector either, the implied value depends on the argument type. For numeric
              options, a value of zero is assumed. For options which take a  string  argument,  a
              NULL  pointer  is returned. For enum options, the first possible value (index zero)
              is taken as the default.

       help   The detailed, multi-line help text for the current option. Included in the man page
              and the long help.


       A minimal suite and the corresponding "application".

       The suite file hello.suite:

            [suite hello]
            [supercommand hello]
                 purpose = hello world
                 [option world]
                      summary = add "world"

       The "application" hello.c:

            #include <stdio.h> /* printf(3) */
            #include <stdlib.h> /* exit(3) */
            #include <lopsub.h>
            #include "hello.lsg.h"

            int main(int argc, char **argv)
                 struct lls_parse_result *lpr;
                 const struct lls_opt_result *result;
                 const struct lls_command *cmd = lls_cmd(0, hello_suite);
                 int ret;

                 ret = lls_parse(argc, argv, cmd, &lpr, NULL);
                 if (ret < 0) {
                      fprintf(stderr, "%s\n", lls_strerror(-ret));
                 result = lls_opt_result(LSG_HELLO_HELLO_OPT_WORLD, lpr);
                 if (lls_opt_given(result))
                      printf(" world");

       Generate hello.lsg.c and hello.lsg.h:

            $ lopsubgen --gen-c --gen-h < hello.suite

       Compile hello.c and hello.lsg.c to produce the hello executable:

            $ cc hello.c hello.lsg.c -o hello -llopsub

       Run it:

            $ ./hello
            $ ./hello --world
            hello world
            $ ./hello -w
            option not recognized
            $ ./hello 42
            invalid number of arguments

       Generate and examine the manual page:

            $ lopsubgen --gen-man < hello.suite
            $ man -l ./


       lopsubgen(1), lopsub(7), lopsubex(1), gengetopt(1), getopt(1), getopt(3)