App::Cmd::Simple (3)

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(The comments found at the beginning of the groff file "man3/App::Cmd::Simple.3pm".)

NAME

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

VERSION

version 0.331

SYNOPSIS

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

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.

usage_desc

This method should be overridden to provide the top level usage line. It's a one-line summary of how the command is to be invoked, and should be given in the format used for the $usage_desc parameter to "describe_options" in Getopt::Long::Descriptive.

If not overridden, it returns something that prints out like:

  yourapp [-?h] [long options...]

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

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

Ricardo Signes <rjbs@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2016 by Ricardo Signes.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.