Sub::SmartMatch - Use smart matching to define multi subs
use Sub::SmartMatch;
use SmartMatch::Sugar qw(any);
# variants will be tried in a given/when
# clause in the order they are defined
multi fact => [ 0 ], sub { 1 };
multi fact => any, sub {
my $n = shift;
return $n * fact($n - 1);
}
This module provides Haskell/ML style subroutine variants based on Perl's smartmatch operator.
This doesn't do argument binding, just value matching.
To define methods use SmartMatch::Sugar's object test:
multi new [ class ] => sub {
# invoked as a class method
}
multi new [ object ] => sub {
# invoked as an object method
# this should clone, i guess
}
This marks this case for exact matching. This means that it will match on \@_, not on the slice <[ @_[0 .. $#$case] ]>.
This only applies to cases which are array references themselves.
Define a variant for the sub name $name.
$case will be smartmatched against an array reference of the arguments to the subroutine.
As a special case to allow variable arguments at the end of the list, if $case is an array reference it will only be matched against the slice of @_ with the corresponding number of elements, not all of @_. Use exactly to do a match on all of @_. This does not apply to an empty array (otherwise that would always match, instead of matching empty arrays).
Define the default for a multi sub. This variant is always tried last if no other variant matched.
Define a multi sub in one go.
def_multi foo => (
$case => $body,
... => ...,
default => $default,
);
SmartMatch::Sugar, Sub::PatternMatch, perlsyn, Class::Multimethods::Pure
This module is maintained using Darcs. You can get the latest version from http://nothingmuch.woobling.org/code, and use darcs send to commit changes.
Yuval Kogman <nothingmuch@woobling.org>
Copyright (c) 2008 Yuval Kogman. All rights reserved
This program is free software; you can redistribute
it and/or modify it under the same terms as Perl itself.
