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signatures(3pm)


NAME

   signatures - Subroutine signatures with no source filter

VERSION

   version 0.13

SYNOPSIS

       use signatures;

       sub foo ($bar, $baz) {
           return $bar + $baz;
       }

DESCRIPTION

   With this module, we can specify subroutine signatures and have
   variables automatically defined within the subroutine.

   For example, you can write

       sub square ($num) {
           return $num * $num;
       }

   and it will be automatically turned into the following at compile time:

       sub square {
           my ($num) = @_;
           return $num * $num;
       }

   Note that, although the syntax is very similar, the signatures provided
   by this module are not to be confused with the prototypes described in
   perlsub. All this module does is extracting items of @_ and assigning
   them to the variables in the parameter list. No argument validation is
   done at runtime.

   The signature definition needs to be on a single line only.

   If you want to combine sub signatures with regular prototypes a "proto"
   attribute exists:

       sub foo ($bar, $baz) : proto($$) { ... }

METHODS

   If you want subroutine signatures doing something that this module
   doesn't provide, like argument validation, typechecking and similar,
   you can subclass it and override the following methods.

   proto_unwrap ($prototype)
   Turns the extracted $prototype into code.

   The default implementation returns "my (${prototype}) = @_;" or an
   empty string, if no prototype is given.

   inject ($offset, $code)
   Inserts a $code string into the line perl currently parses at the given
   $offset. This is only called by the "callback" method.

   callback ($offset, $prototype)
   This gets called as soon as a sub definition with a prototype is
   encountered. Arguments are the $offset within the current line perl is
   parsing and extracted $prototype.

   The default implementation calls "proto_unwrap" with the prototype and
   passes the returned value and the offset to "inject".

BUGS

   prototypes aren't checked for validity yet
       You won't get a warning for invalid prototypes using the "proto"
       attribute, like you normally would with warnings enabled.

   you shouldn't alter $SIG{__WARN__} at compile time
       After this module is loaded you shouldn't make any changes to
       $SIG{__WARN__} during compile time. Changing it before the module
       is loaded or at runtime is fine.

SEE ALSO

   Method::Signatures

   MooseX::Method::Signatures

   Sub::Signatures

   Attribute::Signature

   Perl6::Subs

   Perl6::Parameters

THANKS

   Moritz Lenz and Steffen Schwigon for documentation review and
   improvement.

AUTHOR

   Florian Ragwitz <rafl@debian.org>

CONTRIBUTORS

   *   Karen Etheridge <ether@cpan.org>

   *   Peter Martini <PeterCMartini@GMail.com>

   *   Alexandr Ciornii <alexchorny@gmail.com>

   *   Father Chrysostomos <sprout@cpan.org>

   *   Alex Kapranoff <alex@kapranoff.ru>

   *   Steffen Schwigon <ss5@renormalist.net>

COPYRIGHT AND LICENSE

   This software is copyright (c) 2008 by Florian Ragwitz.

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



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