1SUPER(3)              User Contributed Perl Documentation             SUPER(3)
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NAME

6       SUPER - control superclass method dispatch
7

SYNOPSIS

9       Find the parent method that would run if this weren't here:
10
11           sub my_method
12           {
13               my $self = shift;
14               my $super = $self->super('my_method'); # Who's your daddy?
15
16               if ($want_to_deal_with_this)
17               {
18                   # ...
19               }
20               else
21               {
22                   $super->($self, @_)
23               }
24           }
25
26       Or Ruby-style:
27
28           sub my_method
29           {
30               my $self = shift;
31
32               if ($want_to_deal_with_this)
33               {
34                   # ...
35               }
36               else
37               {
38                   super;
39               }
40           }
41
42       Or call the super method manually, with respect to inheritance, and
43       passing different arguments:
44
45           sub my_method
46           {
47               my $self = shift;
48
49               # parent handles args backwardly
50               $self->SUPER( reverse @_ );
51           }
52

DESCRIPTION

54       When subclassing a class, you occasionally want to dispatch control to
55       the superclass -- at least conditionally and temporarily. The Perl syn‐
56       tax for calling your superclass is ugly and unwieldy:
57
58           $self->SUPER::method(@_);
59
60       especially when compared to its Ruby equivalent:
61
62           super;
63
64       It's even worse in that the normal Perl redispatch mechanism only dis‐
65       patches to the parent of the class containing the method at compile
66       time.  That doesn't work very well for mixins and roles.
67
68       This module provides nicer equivalents, along with the universal method
69       "super" to determine a class' own superclass. This allows you to do
70       things such as:
71
72           goto &{$_[0]->super('my_method')};
73
74       if you don't like wasting precious stack frames. (Because "super"
75       returns a coderef, much like "can" in UNIVERSAL, this doesn't break
76       "use strict 'refs'".)
77
78       If you are using roles or mixins or otherwise pulling in methods from
79       other packages that need to dispatch to their super methods, or if you
80       want to pass different arguments to the super method, use the "SUPER()"
81       method:
82
83           $self->SUPER( qw( other arguments here ) );
84

FUNCTIONS and METHODS

86       This module provides the following functions and methods:
87
88       "super()"
89           This function calls the super method of the currently-executing
90           method, no matter where the super method is in the hierarchy.
91
92           This takes no arguments; it passes the same arguments passed to the
93           currently-executing method.
94
95           The module exports this function by default.
96
97           Note: you must have the appropriate "package" declaration in place
98           for this to work.  That is, you must have compiled the method in
99           which you use this function in the package from which you want to
100           use it.  Them's the breaks with Perl 5.
101
102       "find_parent( $class, $method, $prune, $invocant )"
103           Attempts to find a parent implementation of $method starting with
104           $class.  If you pass $prune, it will not ignore the method found in
105           that package, if it exists there.  Pass $invocant if the object
106           itself might have a different idea of its parents.
107
108           The module does not export this function by default.  Call it
109           directly.
110
111       "get_all_parents( $invocant, $class )"
112           Returns all of the parents for the $invocant, if it supports the
113           "__get_parents()" method or the contents of @ISA for $class.  You
114           probably oughtn't call this on your own.
115
116       "SUPER()"
117           Calls the super method of the currently-executing method.  You can
118           pass arguments.  This is a method.
119

NOTES

121       Beware: if you do weird things with code generation, be sure to name
122       your anonymous subroutines.  See Perl Hacks #57.
123
124       Using "super" doesn't let you pass alternate arguments to your super‐
125       class's method. If you want to pass different arguments, use "SUPER"
126       instead.  D'oh.
127
128       This module does a small amount of Deep Magic to find the arguments of
129       method calling "super()" itself.  This may confuse tools such as
130       "Devel::Cover".
131
132       In your own code, if you do complicated things with proxy objects and
133       the like, define "__get_parents()" to return a list of all parents of
134       the object to which you really want to dispatch.
135

AUTHOR

137       Created by Simon Cozens, "simon@cpan.org".
138
139       Maintained by chromatic, <chromatic at wgz dot org> after version 1.01.
140
141       Thanks to Joshua ben Jore for bug reports and suggestions.
142

LICENSE

144       You may use and distribute this silly little module under the same
145       terms as Perl itself.
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149perl v5.8.8                       2007-04-18                          SUPER(3)