https://github.com/ap/sub-argshortcut

simplify writing functions that use default arguments
https://github.com/ap/sub-argshortcut

perl

Last synced: 10 days ago
JSON representation

simplify writing functions that use default arguments

• Host: GitHub
• URL: https://github.com/ap/sub-argshortcut
• Owner: ap
• Created: 2015-01-05T08:49:04.000Z (almost 10 years ago)
• Default Branch: master
• Last Pushed: 2022-09-04T15:59:08.000Z (over 2 years ago)
• Last Synced: 2024-11-06T03:03:58.682Z (about 2 months ago)
• Topics: perl
• Language: Perl
• Homepage: https://metacpan.org/release/Sub-ArgShortcut
• Size: 17.6 KB
• Stars: 0
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.pod
  • Changelog: Changes

Awesome Lists containing this project

README

        
use 5.006; use strict; use warnings;

package Sub::ArgShortcut;

our $VERSION = '1.022';

sub argshortcut(&) {

	my ( $code ) = @_;

	return sub {

		my @byval;

		my $nondestructive = defined wantarray;

		$code->(

			$nondestructive

			? ( @byval = @_ ? @_ : $_ )

			: (          @_ ? @_ : $_ )

		);

		return $nondestructive ? @byval[ 0 .. $#byval ] : ();

	};

}

sub import {

	my $class = shift;

	my $install_pkg = caller;

	die q(Something mysterious happened) if not defined $install_pkg;

	{ no strict 'refs'; *{"${install_pkg}::argshortcut"} = \&argshortcut; }

}

1;

__END__

=pod

=encoding UTF-8

=head1 NAME

Sub::ArgShortcut - simplify writing functions that use default arguments

=head1 SYNOPSIS

 use Sub::ArgShortcut::Attr;

 sub mychomp : ArgShortcut { chomp @_ }

 while ( <> ) {

     # make a chomped copy of $_ without modifying it

     my $chomped_line = mychomp;

 

     # or, modify $_ in place

     mychomp;

 

     # ...

 }

=head1 DESCRIPTION

This module encapsulates the logic required for functions that assume C<$_> as

their argument when called with an empty argument list, and which modify their

arguments in void context but return modified copies in any other context. You

only need to write code which modifies the elements of C<@_> in-place.

=head1 INTERFACE

=head2 C

This function takes a code reference as input, wraps a function around it and

returns a reference to that function. The code that is passed in should modify

the values in C<@_> in whatever fashion desired. The function from the

L could therefore also be written like this:

 use Sub::ArgShortcut;

 my $mychomp = argshortcut { chomp @_ };

=head2 C<:ArgShortcut>

Instead of using L> to wrap a code reference,

you can write regular subs and then add Sub::ArgShortcut functionality to them

implicitly. Simply C instead of Sub::Shortcut, then

request its behaviour using the C<:ArgShortcut> attribute on functions:

 sub mychomp : ArgShortcut { chomp @_ }

 my $mychomp = sub : ArgShortcut { chomp @_ };

=head1 EXPORTS

Sub::ArgShortcut exports C by default.

=head1 BUGS AND LIMITATIONS

Passing an empty array to a shortcutting function will probably surprise you:

assuming C is a function with C<:ArgShortcut> and C<@bar> is an empty

array, then calling C will cause C to operate on C<$_>! This

is because C has no way of distinguishing whether it was called without

any arguments or called with arguments that evaluate to an empty list.

=cut