NAME
MRO::Compat - mro::* interface compatibility for Perls < 5.9.5
SYNOPSIS
package FooClass; use base qw/X Y Z/;
package X; use base qw/ZZZ/;
package Y; use base qw/ZZZ/;
package Z; use base qw/ZZZ/;
package main;
use MRO::Compat;
my $linear = mro::get_linear_isa('FooClass');
print join(q{, }, @$linear);
# Prints: "FooClass, X, ZZZ, Y, Z"DESCRIPTION
The "mro" namespace provides several utilities for dealing with method resolution order and method caching in general in Perl 5.9.5 and higher.
This module provides those interfaces for earlier versions of Perl (back to 5.6.0 anyways).
It is a harmless no-op to use this module on 5.9.5+. If you're writing a piece of software that would like to use the parts of 5.9.5+'s mro:: interfaces that are supported here, and you want compatibility with older Perls, this is the module for you.
This module never exports any functions. All calls must be fully qualified with the mro:: prefix.
VERSION 0.01_01
This is the first dev release of this new module, and on top of that, the Perl 5.9.5 it seeks to provide compatibility with isn't even out yet. Consider it not fully stabilized for the time being. These interfaces are not necessarily nailed down yet.
Functions
mro::get_linear_isa($classname[, $type])
Returns an arrayref which is the linearized MRO of the given class. Uses whichever MRO is currently in effect for that class by default, or the given MRO (either c3 or dfs if specified as $type).
The linearized MRO of a class is a single ordered list of all of the classes that would be visited in the process of resolving a method on the given class, starting with itself. It does not include any duplicate entries.
Note that UNIVERSAL (and any members of UNIVERSAL's MRO) are not part of the MRO of a class, even though all classes implicitly inherit methods from UNIVERSAL and its parents.
mro::import
This allows the use mro 'dfs' and use mro 'c3' syntaxes, providing you "use MRO::Compat" first. Please see the "USING C3" section for additional details.
mro::set_mro($classname, $type)
Sets the mro of $classname to one of the types dfs or c3. Please see the "USING C3" section for additional details.
mro::get_mro($classname)
Returns the MRO of the given class (either c3 or dfs).
It considers any Class::C3-using class to have C3 MRO even before Class::C3::initialize() is called.
mro::get_isarev($classname)
Returns an array of classes who are subclasses of the given classname. In other words, classes who we exists, however indirectly, in the @ISA inheritancy hierarchy of.
This is much slower on pre-5.9.5 Perls with MRO::Compat than it is on 5.9.5+, as it has to search the entire package namespace.
mro::is_universal($classname)
Returns a boolean status indicating whether or not the given classname is either UNIVERSAL itself, or one of UNIVERSAL's parents by @ISA inheritance.
Any class for which this function returns true is "universal" in the sense that all classes potentially inherit methods from it.
mro::invalidate_all_method_caches
Increments PL_sub_generation, which invalidates method caching in all packages.
mro::method_changed_in($classname)
Invalidates the method cache of any classes dependent on the given class. In MRO::Compat on pre-5.9.5 Perls, this is an alias for mro::invalidate_all_method_caches above, as pre-5.9.5 Perls have no other way to do this. It will still enforce the requirement that you pass it a classname, for compatibility.
USING C3
While this module makes the 5.9.5+ syntaxes use mro 'c3' and mro::set_mro("Foo", 'c3') available on older Perls, it does so merely by passing off the work to Class::C3.
It does not remove the need for you to call Class::C3's initialize(), reinitialize(), and/or uninitialize() at the appropriate times as documented in the Class::C3 docs.
Because MRO::Compat has Class::C3 as a pre-requisite, and requires it at use time, you can blindly call those functions in code that uses MRO::Compat. Under 5.9.5+ with MRO::Compat, your calls to those functions will become a no-op and everything will work fine.
SEE ALSO
AUTHOR
Brandon L. Black, <blblack@gmail.com>
COPYRIGHT AND LICENSE
Copyright 2007 Brandon L. Black <blblack@gmail.com>
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.