Ubuntu Manpage: cmdline - Procedures to process command lines and options.

NAME

       cmdline - Procedures to process command lines and options.

SYNOPSIS

       package require Tcl  8.2

       package require cmdline  ?1.3.3?

       ::cmdline::getopt argvVar optstring optVar valVar

       ::cmdline::getKnownOpt argvVar optstring optVar valVar

       ::cmdline::getoptions arglistVar optlist ?usage?

       ::cmdline::getKnownOptions arglistVar optlist ?usage?

       ::cmdline::usage optlist ?usage?

       ::cmdline::getfiles patterns quiet

       ::cmdline::getArgv0

_________________________________________________________________________________________________

DESCRIPTION

       This package provides commands to parse command lines and options.

::ARGV HANDLING

       One of the most common variables this package will be used with is ::argv, which holds the
       command line of the current application. This variable has a  companion  ::argc  which  is
       initialized to the number of elements in ::argv at the beginning of the application.

       The commands in this package will not modify the ::argc companion when called with ::argv.
       Keeping the value consistent, if such is desired or required, is the responsibility of the
       caller.

API

::cmdline::getopt argvVar optstring optVar valVar
This command works in a fashion like the standard C based getopt function. Given
an option string and a pointer to an array of args this command will process the
first argument and return info on how to proceed. The command returns 1 if an
option was found, 0 if no more options were found, and -1 if an error occurred.

argvVar contains the name of the list of arguments to process. If options are found
the list is modified and the processed arguments are removed from the start of the
list.

optstring contains a list of command options that the application will accept. If
the option ends in ".arg" the command will use the next argument as an argument to
the option, or extract it from the current argument, if it is of the form
"option=value". Otherwise the option is a boolean that is set to 1 if present.

optVar refers to the variable the command will store the found option into (without
the leading '-' and without the .arg extension).

valVar refers to the variable to store either the value for the specified option
into upon success or an error message in the case of failure. The stored value
comes from the command line for .arg options, otherwise the value is 1.

::cmdline::getKnownOpt argvVar optstring optVar valVar
Like ::cmdline::getopt, but ignores any unknown options in the input.

::cmdline::getoptions arglistVar optlist ?usage?
Processes the set of command line options found in the list variable named by
arglistVar and fills in defaults for those not specified. This also generates an
error message that lists the allowed flags if an incorrect flag is specified. The
optional usage-argument contains a string to include in front of the generated
message. If not present it defaults to "options:".

optlist contains a list of lists where each element specifies an option in the
form: flag default comment.

If flag ends in ".arg" then the value is taken from the command line. Otherwise it
is a boolean and appears in the result if present on the command line. If flag ends
in ".secret", it will not be displayed in the usage.

The options -?, -help, and -- are implicitly understood. The first two abort option
processing by throwing an error and force the generation of the usage message,
whereas the the last aborts option processing without an error, leaving all
arguments coming after for regular processing, even if starting with a dash.

The result of the command is a dictionary mapping all options to their values, be
they user-specified or defaults.

::cmdline::getKnownOptions arglistVar optlist ?usage?
Like ::cmdline::getoptions, but ignores any unknown options in the input.

::cmdline::usage optlist ?usage?
Generates and returns an error message that lists the allowed flags. optlist is
defined as for ::cmdline::getoptions. The optional usage-argument contains a string
to include in front of the generated message. If not present it defaults to
"options:".

::cmdline::getfiles patterns quiet
Given a list of file patterns this command computes the set of valid files. On
windows, file globbing is performed on each argument. On Unix, only file existence
is tested. If a file argument produces no valid files, a warning is optionally
generated (set quiet to true).

This code also uses the full path for each file. If not given it prepends the
current working directory to the filename. This ensures that these files will never
conflict with files in a wrapped zip file. The last sentence refers to the pro-
tools.

::cmdline::getArgv0
This command returns the "sanitized" version of argv0. It will strip off the
leading path and removes the extension ".bin". The latter is used by the pro-apps
because they must be wrapped by a shell script.

ERROR CODES
Starting with version 1.5 all errors thrown by the package have a proper ::errorCode for
use with Tcl's try command. This code always has the word CMDLINE as its first element.

EXAMPLES

                      package require Tcl 8.5
                      package require try         ;# Tcllib.
                      package require cmdline 1.5 ;# First version with proper error-codes.

                      # Notes:
                      # - Tcl 8.6+ has 'try' as a builtin command and therefore does not
                      #   need the 'try' package.
                      # - Before Tcl 8.5 we cannot support 'try' and have to use 'catch'.
                      #   This then requires a dedicated test (if) on the contents of
                      #   ::errorCode to separate the CMDLINE USAGE signal from actual errors.

                      set options {
                          {a          "set the atime only"}
                          {m          "set the mtime only"}
                          {c          "do not create non-existent files"}
                          {r.arg  ""  "use time from ref_file"}
                          {t.arg  -1  "use specified time"}
                      }
                      set usage ": MyCommandName \[options] filename ...\noptions:"

                      try {
                          array set params [::cmdline::getoptions argv $options $usage]
                      } trap {CMDLINE USAGE} {msg o} {
                          # Trap the usage signal, print the message, and exit the application.
                          # Note: Other errors are not caught and passed through to higher levels!
                    puts $msg
                    exit 1
                      }

                      if {  $params(a) } { set set_atime "true" }
                      set has_t [expr {$params(t) != -1}]
                      set has_r [expr {[string length $params(r)] > 0}]
                      if {$has_t && $has_r} {
                          return -code error "Cannot specify both -r and -t"
                      } elseif {$has_t} {
                    ...
                      }

       This  example,  taken  (and slightly modified) from the package fileutil, shows how to use
       cmdline.  First, a list of options is created, then the 'args' list is passed  to  cmdline
       for  processing.   Subsequently,  different  options  are checked to see if they have been
       passed to the script, and what their value is.

BUGS, IDEAS, FEEDBACK

       This document, and the package it describes,  will  undoubtedly  contain  bugs  and  other
       problems.    Please   report   such  in  the  category  cmdline  of  the  Tcllib  Trackers
       [http://core.tcl.tk/tcllib/reportlist].  Please also report any ideas for enhancements you
       may have for either package and/or documentation.

KEYWORDS

       argument processing, argv, argv0, cmdline processing, command line processing