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| author | Franck Cuny <franckcuny@gmail.com> | 2016-08-04 11:45:44 -0700 |
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| committer | Franck Cuny <franckcuny@gmail.com> | 2016-08-04 11:45:44 -0700 |
| commit | 585b48b6a605cb71ef99dd767880e1b7ee5bf24e (patch) | |
| tree | c65377350d12bd1e62e0bdd58458c1044541c27b /posts/2009-06-22-modules-i-like-getopt-long-and-moosex-getopt.md | |
| parent | Use Bullet list for the index. (diff) | |
| parent | Mass convert all posts from markdown to org. (diff) | |
| download | lumberjaph-585b48b6a605cb71ef99dd767880e1b7ee5bf24e.tar.gz | |
Merge branch 'convert-to-org'
Diffstat (limited to 'posts/2009-06-22-modules-i-like-getopt-long-and-moosex-getopt.md')
| -rw-r--r-- | posts/2009-06-22-modules-i-like-getopt-long-and-moosex-getopt.md | 123 |
1 files changed, 0 insertions, 123 deletions
diff --git a/posts/2009-06-22-modules-i-like-getopt-long-and-moosex-getopt.md b/posts/2009-06-22-modules-i-like-getopt-long-and-moosex-getopt.md deleted file mode 100644 index 65a635d..0000000 --- a/posts/2009-06-22-modules-i-like-getopt-long-and-moosex-getopt.md +++ /dev/null @@ -1,123 +0,0 @@ -## Getopt::Long - -[Getopt::long](http://search.cpan.org/perldoc?Getopt::Long) is a useful module to parse command line arguements. - -A basic usage is something like this: - -```perl -#!/usr/bin/perl -w -use strict; -use YAML::Syck; -use Getopt::Long; - -GetOptions('config=s' => \my $cfg_file,); - -my $config = LoadFile $cfg_file -``` - -In **GetOptions**, we require a value for config with **config=s**. If we wante an integer, we replace 's' with 'i', and for a floating point, with 'f'. - -Call your script : - -```bash -% script.pl --config=file.yml #this one works -% script.pl --config file.yml #this one too! -% script.pl -c file.yml #and this one too -``` - -The three syntaxes are understood. - -A good practices is to combine this module with [Pod::Usage](http://search.cpan.org/perldoc?Pod::Usage). Let's do some modifications on the example: - -```perl -#!/usr/bin/perl -w -use strict; -use YAML::Syck; -use Getopt::Long; -use Pod::Usage; - -GetOptions('config=s' => \my $cfg_file,) or pod2usage(2); -pod2usage(2) unless @ARGV > 0; - -my $config = LoadFile $cfg_file - -__END__ -=head1 NAME - -uberscript - -=head1 SYNOPSIS - -uberscript [options] - -Options: - - --config config file - -=head1 Options - -=over 4 - -=item B<config> - -Path to the config file -``` - -then - -```bash -% perl uberscript - -Usage: - uberscript [options] - - Options: - --config config file -``` - -From now if we call our script without argument, the POD will be printed on STDIN. - -## MooseX::Getopt - -[MooseX::Getopt](http://search.cpan.org/perldoc?MooseX::Getopt) is a Role that add a `new_with_options` to your object. We create a basic Object : - -```perl -package OurShinyObject; - -use Moose; -with qw/MooseX::Getopt/; - -has 'config' => (isa => 'Str', is => 'ro', required => 1); -has 'context' => ( - isa => 'HashRef', - is => 'rw', - lazy => 1, - traits => ['NoGetopt'], - default => sub { LoadFile shift->config } -); - -... -``` - -create a script to call this object - -```perl -#!/usr/bin/perl -w -use strict; -use OurShinyObject; - -my $obj = OurShinyObject->new_from_options(); - -``` - -```sh -% script.pl --config file.yml -``` - -The role will set our attribute **context** using the value from the argument set on the command line. - -The `traits => ['NoGetopt']` indicate that this attributes will be not be read from the command line. An alternate way to do this is to prefix the attributes with **_**. - -## conclusion (?) - -When you write a script, even if you're sure you will never need to have more than one argument, or that you never will have to update the code, *please* consider to use of **Getopt::Long** instead of a `shift @ARGV`, because we all know that you will at a certain point update this script and you will more than one argument :). |
