SUPER(3) User Contributed Perl Documentation SUPER(3)NAMESUPER - control superclass method dispatch
SYNOPSIS
Find the parent method that would run if this weren't here:
sub my_method
{
my $self = shift;
my $super = $self->super('my_method'); # Who's your daddy?
if ($want_to_deal_with_this)
{
# ...
}
else
{
$super->($self, @_)
}
}
Or Ruby-style:
sub my_method
{
my $self = shift;
if ($want_to_deal_with_this)
{
# ...
}
else
{
super;
}
}
Or call the super method manually, with respect to inheritance, and
passing different arguments:
sub my_method
{
my $self = shift;
# parent handles args backwardly
$self->SUPER( reverse @_ );
}
DESCRIPTION
When subclassing a class, you occasionally want to dispatch control to
the superclass -- at least conditionally and temporarily. The Perl
syntax for calling your superclass is ugly and unwieldy:
$self->SUPER::method(@_);
especially when compared to its Ruby equivalent:
super;
It's even worse in that the normal Perl redispatch mechanism only
dispatches to the parent of the class containing the method at compile
time. That doesn't work very well for mixins and roles.
This module provides nicer equivalents, along with the universal method
"super" to determine a class' own superclass. This allows you to do
things such as:
goto &{$_[0]->super('my_method')};
if you don't like wasting precious stack frames. (Because "super"
returns a coderef, much like "can" in UNIVERSAL, this doesn't break
"use strict 'refs'".)
If you are using roles or mixins or otherwise pulling in methods from
other packages that need to dispatch to their super methods, or if you
want to pass different arguments to the super method, use the "SUPER()"
method:
$self->SUPER( qw( other arguments here ) );
FUNCTIONS and METHODS
This module provides the following functions and methods:
"super()"
This function calls the super method of the currently-executing
method, no matter where the super method is in the hierarchy.
This takes no arguments; it passes the same arguments passed to the
currently-executing method.
The module exports this function by default.
Note: you must have the appropriate "package" declaration in place
for this to work. That is, you must have compiled the method in
which you use this function in the package from which you want to
use it. Them's the breaks with Perl 5.
"find_parent( $class, $method, $prune, $invocant )"
Attempts to find a parent implementation of $method starting with
$class. If you pass $prune, it will not ignore the method found in
that package, if it exists there. Pass $invocant if the object
itself might have a different idea of its parents.
The module does not export this function by default. Call it
directly.
"get_all_parents( $invocant, $class )"
Returns all of the parents for the $invocant, if it supports the
"__get_parents()" method or the contents of @ISA for $class. You
probably oughtn't call this on your own.
"SUPER()"
Calls the super method of the currently-executing method. You can
pass arguments. This is a method.
NOTES
Beware: if you do weird things with code generation, be sure to name
your anonymous subroutines. See Perl Hacks #57.
Using "super" doesn't let you pass alternate arguments to your
superclass's method. If you want to pass different arguments, use
"SUPER" instead. D'oh.
This module does a small amount of Deep Magic to find the arguments of
method calling "super()" itself. This may confuse tools such as
"Devel::Cover".
In your own code, if you do complicated things with proxy objects and
the like, define "__get_parents()" to return a list of all parents of
the object to which you really want to dispatch.
AUTHOR
Created by Simon Cozens, "simon@cpan.org". Copyright (c) 2003 Simon
Cozens.
Maintained by chromatic, <chromatic at wgz dot org> after version 1.01.
Copyright (c) 2004-2009 chromatic.
Thanks to Joshua ben Jore for bug reports and suggestions.
LICENSE
You may use and distribute this silly little module under the same
terms as Perl itself.
perl v5.14.2 2012-03-06 SUPER(3)
