use strict;
use warnings;
-# mro.pm versions < 1.00 reserved for possible CPAN mro dist
-# (for partial back-compat to 5.[68].x)
+# mro.pm versions < 1.00 reserved for MRO::Compat
+# for partial back-compat to 5.[68].x
our $VERSION = '1.00';
sub import {
mro::set_mro(scalar(caller), $_[1]) if $_[1];
}
+package # hide me from PAUSE
+ next;
+
+sub can { mro::_nextcan($_[0], 0) }
+
+sub method {
+ my $method = mro::_nextcan($_[0], 1);
+ goto &$method;
+}
+
+package # hide me from PAUSE
+ maybe::next;
+
+sub method {
+ my $method = mro::_nextcan($_[0], 0);
+ goto &$method if defined $method;
+ return;
+}
+
1;
__END__
=head1 SYNOPSIS
+ use mro; # enables next::method and friends globally
+
use mro 'dfs'; # enable DFS MRO for this class (Perl default)
use mro 'c3'; # enable C3 MRO for this class
It's possible to change the MRO of a given class either by using C<use
mro> as shown in the synopsis, or by using the L</mro::set_mro> function
-below. The functions do not require loading the C<mro> module, as they
-are actually provided by the core perl interpreter. The C<use mro> syntax
-is just syntactic sugar for setting the current package's MRO.
+below. The functions in the mro namespace do not require loading the
+C<mro> module, as they are actually provided by the core perl interpreter.
+
+The special methods C<next::method>, C<next::can>, and
+C<maybe::next::method> are not available until this C<mro> module
+has been loaded via C<use> or C<require>.
=head1 The C3 MRO
In simple cases, it is equivalent to:
- $self->next::method(@_) if $self->next_can;
+ $self->next::method(@_) if $self->next::can;
But there are some cases where only this solution
works (like C<goto &maybe::next::method>);
-=head1 PERFORMANCE CONSIDERATIONS
-
-Specifying the mro type of a class before setting C<@ISA> will
-be faster than the other way around. Also, making all of your
-C<@ISA> manipulations in a single assignment statement will be
-faster that doing them one by one via C<push> (which is what
-C<use base> does currently).
-
-Examples:
-
- # The slowest way
- package Foo;
- use base qw/A B C/;
- use mro 'c3';
-
- # The fastest way
- # (not exactly equivalent to above,
- # as base.pm can do other magic)
- use mro 'c3';
- use A ();
- use B ();
- use C ();
- our @ISA = qw/A B C/;
-
-Generally speaking, every time C<@ISA> is modified, the MRO
-of that class will be recalculated, because of the way array
-magic works. Pushing multiple items onto C<@ISA> in one push
-statement still counts as multiple modifications. However,
-assigning a list to C<@ISA> only counts as a single
-modification. Thus if you really need to do C<push> as
-opposed to assignment, C<@ISA = (@ISA, qw/A B C/);>
-will still be faster than C<push(@ISA, qw/A B C/);>
-
=head1 SEE ALSO
=head2 The original Dylan paper