NAME
Kavorka - function signatures with the lure of the animal
SYNOPSIS
use Kavorka;
fun maxnum (Num @numbers) {
my $max = shift @numbers;
for (@numbers) {
$max = $_ if $max < $_;
}
return $max;
}
my $biggest = maxnum(42, 3.14159, 666);
STATUS
Kavorka is still at a very early stage of development; there are likely to
be many bugs that still need to be shaken out. Certain syntax features are
a little odd and may need to be changed in incompatible ways.
DESCRIPTION
Kavorka provides `fun` and `method` keywords for declaring functions and
methods. It uses Perl 5.14's keyword API, so should work more reliably
than source filters or Devel::Declare-based modules.
The syntax provided by Kavorka is largely inspired by Perl 6, though it
has also been greatly influenced by Method::Signatures and
Function::Parameters.
For information using the keywords exported by Kavorka:
* Kavorka::Manual::Functions
* Kavorka::Manual::Methods
* Kavorka::Manual::MethodModifiers
* Kavorka::Manual::MultiSubs
Exports
`-default`
Exports `fun` and `method`.
`-modifiers`
Exports `before`, `after`, and `around`.
`-allmodifiers`
Exports `before`, `after`, `around`, `augment`, and `override`.
`-all`
Exports `fun`, `method`, `before`, `after`, `around`, `augment`,
`override`, `classmethod`, `objectmethod`, and `multi`.
For example:
# Everything except objectmethod and multi...
use Kavorka qw( -default -allmodifiers classmethod );
You can rename imported functions:
use Kavorka method => { -as => 'meth' };
You can provide alternative implementations:
# use My::Sub::Method instead of Kavorka::Sub::Method
use Kavorka method => { implementation => 'My::Sub::Method' };
Or add traits to the default implementation:
use Kavorka method => { traits => ['My::Sub::Role::Foo'] };
See Exporter::Tiny for more tips.
Function Introspection API
The coderef for any sub created by Kavorka can be passed to the
`Kavorka->info` method. This returns a blessed object that does the
Kavorka::Sub role.
fun foo (:$x, :$y) { }
my $info = Kavorka->info(\&foo);
my $function_name = $info->qualified_name;
my @named_params = $info->signature->named_params;
say $named_params[0]->named_names->[0]; # says 'x'
See Kavorka::Sub, Kavorka::Signature and Kavorka::Parameter for further
details.
If you're using Moose, consider using MooseX::KavorkaInfo to expose
Kavorka method signatures via the meta object protocol.
Kavorka::Manual::API provides more details and examples using the
introspection API.
CAVEATS
* As noted in Kavorka::Manual::PrototypeAndAttributes, subroutine
attributes don't work properly for anonymous functions.
* This module is based on Parse::Keyword, which has a chronically broken
implementation of closures. Kavorka uses PadWalker to attempt to work
around the problem. This mostly seems to work, but you may experience
some problems in edge cases, especially for anonymous functions and
methods.
* If importing Kavorka's method modifiers into Moo/Mouse/Moose classes,
pay attention to load order:
use Moose;
use Kavorka -all; # ok
If you do it this way, Moose's `before`, `after`, and `around`
keywords will stomp on top of Kavorka's...
use Kavorka -all;
use Moose; # STOMP, STOMP, STOMP! :-(
This can lead to delightfully hard to debug errors.
BUGS
Please report any bugs to
<http://rt.cpan.org/Dist/Display.html?Queue=Kavorka>.
SUPPORT
IRC: support is available through in the *#moops* channel on irc.perl.org
<http://www.irc.perl.org/channels.html>.
SEE ALSO
Kavorka::Manual.
Inspirations: <http://perlcabal.org/syn/S06.html>, Function::Parameters,
Method::Signatures.
<http://en.wikipedia.org/wiki/The_Conversion_(Seinfeld)>.
AUTHOR
Toby Inkster <tobyink@cpan.org>.
COPYRIGHT AND LICENCE
This software is copyright (c) 2013-2014 by Toby Inkster.
This is free software; you can redistribute it and/or modify it under the
same terms as the Perl 5 programming language system itself.
DISCLAIMER OF WARRANTIES
THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.