signatures - Subroutine signatures with no source filter

       Florian Ragwitz <rafl@debian.org>

       •   Karen Etheridge <ether@cpan.org>

       •   Peter Martini <PeterCMartini@GMail.com>

       •   Father Chrysostomos <sprout@cpan.org>

       •   Alex Kapranoff <alex@kapranoff.ru>

       •   Steffen Schwigon <ss5@renormalist.net>

       •   Alexandr Ciornii <alexchorny@gmail.com>

       •   Dave Mitchell <davem@iabyn.com>

       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.

perl v5.40.0                                       2024-10-20                                    signatures(3pm)

       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($$) { ... }

       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.

       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".

       signatures - Subroutine signatures with no source filter

       •   Method::Signatures

       •   MooseX::Method::Signatures

       •   Sub::Signatures

       •   Attribute::Signature

       •   Perl6::Subs

       •   Perl6::Parameters

       Bugs         may        be        submitted        through        the        RT        bug        tracker
       <https://rt.cpan.org/Public/Dist/Display.html?Name=signatures>       (or       bug-signatures@rt.cpan.org
       <mailto:bug-signatures@rt.cpan.org>).

           use signatures;

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

       Moritz Lenz and Steffen Schwigon for documentation review and improvement.

       version 0.14