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Commandable::Finder::SubAttributes(3pm) User Contributed Perl Documentation Commandable::Finder::SubAttributes(3pm)

"Commandable::Finder::SubAttributes" - find commands stored as subs with attributes

   use Commandable::Finder::SubAttributes;
   my $finder = Commandable::Finder::SubAttributes->new(
      package => "MyApp::Commands",
   );
   my $help_command = $finder->find_command( "help" );
   foreach my $command ( $finder->find_commands ) {
      ...
   }

This implementation of Commandable::Finder looks for functions that define commands, where each command is provided by an individual sub in a given package.

   use Commandable::Finder::SubAttributes ':attrs';
   sub command_example
      :Command_description("An example of a command")
   {
      ...
   }

Properties about each command are stored as attributes on the named function, using Attribute::Storage.

The following attributes are available on the calling package when imported with the ":attrs" symbol:

   :Command_description("description text")

Gives a plain string description text for the command.

   :Command_arg("argname", "description")

Gives a named argument for the command and its description.

If the name is suffixed by a "?", this argument is optional. (The "?" itself will be removed from the name).

If the name is suffixed by "...", this argument is slurpy. (The "..." itself will be removed from the name).

   :Command_opt("optname", "description")

Gives a named option for the command and its description.

If the name contains "|" characters it provides multiple name aliases for the same option.

If the name field ends in a ":" character, a value is expected for the option. It can either be parsed from the next input token, or after an "=" sign of the same token:

   --optname VALUE
   --optname=VALUE

An optional third argument may be present to specify a default value, if not provided by the invocation:

   :Command_opt("optname", "description", "default")


   $finder = Commandable::Finder::SubAttributes->new( %args )

Constructs a new instance of "Commandable::Finder::SubAttributes".

Takes the following named arguments:

The name of the package to look in for command subs.
Optional. Gives the name prefix to use to filter for subs that actually provide a command, and to strip off to find the name of the command. Default "command_".
Optional. If true, sub names that contain underscores will be converted into hyphens. This is often useful in CLI systems, allowing commands to be typed with hyphenated names (e.g. "get-thing") while the Perl sub that implements it is named with an underscores (e.g. "command_get_thing"). Defaults true, but can be disabled by passing a defined-but-false value such as 0 or ''.

Any additional arguments are passed to the "configure" method to be used as configuration options.

   $finder = Commandable::Finder::SubAttributes->new_for_caller( %args )
   $finder = Commandable::Finder::SubAttributes->new_for_main( %args )

Convenient wrapper constructors that pass either the caller's package name or "main" as the package name. Combined with the "find_and_invoke_ARGV" method these are particularly convenient for wrapper scripts:

   #!/usr/bin/perl
   use v5.14;
   use warnings;
   use Commandable::Finder::SubAttributes ':attrs';
   exit Commandable::Finder::SubAttributes->new_for_main
      ->find_and_invoke_ARGV;
   # command subs go here...

Paul Evans <leonerd@leonerd.org.uk>

2023-01-08 perl v5.36.0