NAME¶
signatures - Subroutine signatures with no source filter
VERSION¶
version 0.09
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>
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.
CONTRIBUTORS¶
- •
- Alex Kapranoff <alex@kapranoff.ru>
- •
- Alexandr Ciornii <alexchorny@gmail.com>
- •
- Karen Etheridge <ether@cpan.org>
- •
- Peter Martini <PeterCMartini@GMail.com>
- •
- Steffen Schwigon <ss5@renormalist.net>