App::Cmd::Simple - a helper for building one-command App::Cmd applications


App-Cmd documentation Contained in the App-Cmd distribution.

Index


Code Index:

NAME

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App::Cmd::Simple - a helper for building one-command App::Cmd applications

VERSION

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version 0.311

SYNOPSIS

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in simplecmd:

  use YourApp::Cmd;
  Your::Cmd->run;

in YourApp/Cmd.pm:

  package YourApp::Cmd;
  use base qw(App::Cmd::Simple);

  sub opt_spec {
    return (
      [ "blortex|X",  "use the blortex algorithm" ],
      [ "recheck|r",  "recheck all results"       ],
    );
  }

  sub validate_args {
    my ($self, $opt, $args) = @_;

    # no args allowed but options!
    $self->usage_error("No args allowed") if @$args;
  }

  sub execute {
    my ($self, $opt, $args) = @_;

    my $result = $opt->{blortex} ? blortex() : blort();

    recheck($result) if $opt->{recheck};

    print $result;
  }

and, finally, at the command line:

  knight!rjbs$ simplecmd --recheck

  All blorts successful.

SUBCLASSING

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When writing a subclass of App::Cmd:Simple, there are only a few methods that you might want to implement. They behave just like the same-named methods in App::Cmd.

opt_spec

This method should be overridden to provide option specifications. (This is list of arguments passed to describe_options from Getopt::Long::Descriptive, after the first.)

If not overridden, it returns an empty list.

validate_args

  $cmd->validate_args(\%opt, \@args);

This method is passed a hashref of command line options (as processed by Getopt::Long::Descriptive) and an arrayref of leftover arguments. It may throw an exception (preferably by calling usage_error) if they are invalid, or it may do nothing to allow processing to continue.

execute

  Your::App::Cmd::Simple->execute(\%opt, \@args);

This method does whatever it is the command should do! It is passed a hash reference of the parsed command-line options and an array reference of left over arguments.

WARNINGS

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This should be considered experimental! Although it is probably not going to change much, don't build your business model around it yet, okay?

App::Cmd::Simple is not rich in black magic, but it does do some somewhat gnarly things to make an App::Cmd::Simple look as much like an App::Cmd::Command as possible. This means that you can't deviate too much from the sort of thing shown in the synopsis as you might like. If you're doing something other than writing a fairly simple command, and you want to screw around with the App::Cmd-iness of your program, Simple might not be the best choice.

One specific warning... if you are writing a program with the App::Cmd::Simple class embedded in it, you must call import on the class. That's how things work. You can just do this:

  YourApp::Cmd->import->run;

AUTHOR

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Ricardo Signes <rjbs@cpan.org>

COPYRIGHT AND LICENSE

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App-Cmd documentation Contained in the App-Cmd distribution.

use strict;
use warnings;

package App::Cmd::Simple;
BEGIN {
  $App::Cmd::Simple::VERSION = '0.311';
}
use App::Cmd::Command;
BEGIN { our @ISA = 'App::Cmd::Command' }

# ABSTRACT: a helper for building one-command App::Cmd applications

use App::Cmd;
use Sub::Install;


# The idea here is that the user will someday replace "Simple" in his ISA with
# "Command" and then write a standard App::Cmd package.  To make that possible,
# we produce a behind-the-scenes App::Cmd object when the user says 'use
# MyApp::Simple' and redirect MyApp::Simple->run to that.
my $i;
BEGIN { $i = 0 }

sub import {
  my ($class) = @_;
  return if $class eq __PACKAGE__;

  # This signals that something has already set the target up.
  return $class if $class->_cmd_pkg;

  my $core_execute = App::Cmd::Command->can('execute');
  my $our_execute  = $class->can('execute');
  Carp::confess(
    "App::Cmd::Simple subclasses must implement ->execute, not ->run"
  ) unless $our_execute and $our_execute != $core_execute;

  # I doubt the $i will ever be needed, but let's start paranoid.
  my $generated_name = join('::', $class, '_App_Cmd', $i++);

  {
    no strict 'refs';
    *{$generated_name . '::ISA'} = [ 'App::Cmd' ];
  }

  Sub::Install::install_sub({
    into => $class,
    as   => '_cmd_pkg',
    code => sub { $generated_name },
  });

  Sub::Install::install_sub({
    into => $generated_name,
    as   => '_command',
    code => sub { { only => $class } },
  });

  Sub::Install::install_sub({
    into => $generated_name,
    as   => 'default_command',
    code => sub { 'only' },
  });

  Sub::Install::install_sub({
    into => $generated_name,
    as   => '_cmd_from_args',
    code => sub {
      my ($self, $args) = @_;

      return ('only', $args);
    },
  });

  Sub::Install::install_sub({
    into => $class,
    as   => 'run',
    code => sub {
      $generated_name->new({
        no_help_plugin     => 1,
        no_commands_plugin => 1,
      })->run(@_);
    }
  });

  return $class;
}

sub usage_desc {
  return "%c %o"
}

sub _cmd_pkg { }


1;

__END__