g.parser

Langue: en

Autres versions - même langue

Version: 370481 (fedora - 01/12/10)

Section: 1 (Commandes utilisateur)

NAME

g.parser

DESCRIPTION

The g.parser module provides full parser support for GRASS scripts, including an auto-generated GUI interface, help page template, and command line option checking. In this way a simple script can very quickly be made into a full-fledged GRASS module.

OPTIONS

After parsing the arguments are stored in environment variables for use in your scripts. These variables are named "GIS_FLAG_" for flags and dqGIS_OPT_" for options. The names of variables are converted to upper case. For example if an option with key input was defined in the script header, the value will be available in variable GIS_OPT_INPUT and the value of flag with key f will be available in variable GIS_FLAG_F.

For flags, the value will be "1" if the flag was given, and "0" otherwise.

Typical header definitions are as follows:
#%Module
#% description: g.parser test script
#%End
#%flag
#% key: f
#% description: A flag
#%end
#%option
#% key: raster
#% type: string
#% gisprompt: old,cell,raster
#% description: Raster input map
#% required : yes
#%end

NOTES

An option can be instructed to allow multiple inputs by adding the following line:
While this will only directly change the Usage section of the help
screen, the option's environmental string may be easily parsed from within
a script. For example, individual comma separated identities for an option
named "input" can be parsed with the following Bash shell code:


for opt in $GIS_OPT_INPUT ; do

    ... "$opt"
done

A "guisection" field may be added to each option and flag to specify that the options should appear in multiple tabs in the auto-generated GUI. Any options without a guisection field go into the "Options" tab. For example:
would put that option in a tab named tabname.


A "<tt>key_desc" field may be added to each option to specify the text that
appears in the module's usage help section. For example:

added to an input option would create the usage summary
<tt>[input=filename].


If a script is run with --o, G_parser() will set <tt>GRASS_OVERWRITE=1,
which has the same effect as passing --o to every module which is run
from the script.
Similarly, passing --q or --v will set <tt>GRASS_VERBOSE to 0 or 3
respectively, which has the same effect as passing --q or --v to every
module which is run from the script.
Rather than checking whether --o, --q or --v were used, you should be
checking $GRASS_OVERWRITE and/or $GRASS_VERBOSE instead. If those
variables are set, the script should behave the same way regardless of
whether they were set by --o, --q or --v being passed to the script or
set by other means.

AUTOMATED SCRIPT CREATION



The flag --script added to a GRASS command,
To write out a g.parser boilerplate for easy prototyping of shell
scripts, the flag --script can be added to any GRASS command. Example:


v.in.db --script

TRANSLATION

g.parser provides some support for translating the options of scripts. If called with the -t switch before the script filename like this
g.parser -t somescriptfile
g.parser will print the text of the translatable options to stdout, one per line, and exit. This is for internal use within the build system to prepare GRASS scripts for translation.

EXAMPLES

Example code for SHELL


#!/bin/sh

# g.parser demo script for shell programing

#%Module
#% description: g.parser test script
#%End
#%flag
#% key: f
#% description: A flag
#%END
#%option
#% key: raster
#% type: string
#% gisprompt: old,cell,raster
#% description: Raster input map
#% required : yes
#%end
#%option
#% key: vector
#% type: string
#% gisprompt: old,vector,vector
#% description: Vector input map
#% required : yes
#%end
#%option
#% key: option1
#% type: string
#% description: An option
#% required : no
#%end

if [ -z "$GISBASE" ] ; then

    echo "You must be in GRASS GIS to run this program." 1>&2

    exit 1
fi

if [ "$1" != "@ARGS_PARSED@" ] ; then

    exec g.parser "$0" "$@"
fi

#### add your code below ####
echo ""

if [ $GIS_FLAG_F -eq 1 ] ; then

    echo "Flag -f set"
else

    echo "Flag -f not set"
fi

# test if parameter present:
if [ -n "$GIS_OPT_OPTION1" ] ; then

    echo "Value of GIS_OPT_OPTION1: '$GIS_OPT_OPTION1'"
fi

echo "Value of GIS_OPT_RASTER: '$GIS_OPT_RASTER'"
echo "Value of GIS_OPT_VECTOR: '$GIS_OPT_VECTOR'"

Example code for Python


#!/usr/bin/python

# g.parser demo script for python programing

#%Module
#% description: g.parser test script (python)
#%End
#%flag
#% key: f
#% description: A flag
#%END
#%option
#% key: raster
#% type: string
#% gisprompt: old,cell,raster
#% description: Raster input map
#% required : yes
#%end
#%option
#% key: vector
#% type: string
#% gisprompt: old,vector,vector
#% description: Vector input map
#% required : yes
#%end
#%option
#% key: option1
#% type: string
#% description: An option
#% required : no
#%end

import os
import sys

def main():


    #### add your code here ####


    print ""


    if ( os.getenv('GIS_FLAG_F') == "1" ):

        print "Flag -f set"

    else:

        print "Flag -f not set"


    # test if parameter present:

    if ( os.getenv("GIS_OPT_OPTION1") != "" ):

        print "Value of GIS_OPT_OPTION1: '%s'" % os.getenv('GIS_OPT_OPTION1')


    print "Value of GIS_OPT_RASTER: '%s'" % os.getenv('GIS_OPT_RASTER')

    print "Value of GIS_OPT_VECTOR: '%s'" % os.getenv('GIS_OPT_VECTOR')


    #### end of your code ####

    return

if __name__ == "__main__":


    if !os.getenv("GISBASE"):

        print >> sys.stderr, "You must be in GRASS GIS to run this program."

        sys.exit(0)


    if ( len(sys.argv) <= 1 or sys.argv[1] != "@ARGS_PARSED@" ):

        os.execvp("g.parser", [sys.argv[0]] + sys.argv)

    else:

        main();

The test.py script will provide following help text:




Description:

 g.parser test script (python)

 
Usage:

 test.sh [-f] option=name

 
Flags:

  -f   a flag

 
Parameters:

  option   an option

Example code for Perl


#!/usr/bin/perl -w
use strict;

# g.parser demo script

#%Module
#% description: g.parser test script (perl)
#% keywords: keyword1, keyword2
#%End
#%flag
#% key: f
#% description: A flag
#%END
#%option
#% key: raster
#% type: string
#% gisprompt: old,cell,raster
#% description: Raster input map
#% required : yes
#%end
#%option
#% key: vector
#% type: string
#% gisprompt: old,vector,vector
#% description: Vector input map
#% required : yes
#%end
#%option
#% key: option1
#% type: string
#% description: An option
#% required : no
#%end

if ( !$ENV{'GISBASE'} ) {

    printf(STDERR  "You must be in GRASS GIS to run this program.rsn");

    exit 1;
}


 
if( $ARGV[0] ne '@ARGS_PARSED@' ){

    my $arg = "";

    for (my $i=0; $i < @ARGV;$i++) {

        $arg .= " $ARGV[$i] ";

    }

    system("$ENV{GISBASE}/bin/g.parser $0 $arg");

    exit;
}

#### add your code here ####
print "rsn";
if ( $ENV{'GIS_FLAG_F'} eq "1" ){

   print "Flag -f setrsn"
}
else {

   print "Flag -f not setrsn"
}

printf ("Value of GIS_OPT_option1: '%s'rsn", $ENV{'GIS_OPT_OPTION1'});
printf ("Value of GIS_OPT_raster: '%s'rsn", $ENV{'GIS_OPT_RASTER'});
printf ("Value of GIS_OPT_vect: '%s'rsn", $ENV{'GIS_OPT_VECTOR'});

#### end of your code ####

The test.pl script will provide following help text:




Description:

 g.parser test script (perl)

 
Usage:

 test.sh [-f] option=name

 
Flags:

  -f   a flag

 
Parameters:

  option   an option

SEE ALSO

d.ask, d.menu, g.ask, g.filename, g.findfile, g.tempfile, and the SUBMITTING_SCRIPTS file in the GRASS source code.

AUTHOR

Glynn Clements

Last changed: $Date: 2007-07-16 11:19:50 +0200 (Mon, 16 Jul 2007) $