1UNIVERSAL::ref(3)     User Contributed Perl Documentation    UNIVERSAL::ref(3)
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NAME

6       UNIVERSAL::ref - Turns ref() into a multimethod
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SYNOPSIS

9         # True! Wrapper pretends to be Thing.
10         ref( Wrapper->new( Thing->new ) )
11           eq ref( Thing->new );
12
13         package Thing;
14         sub new { bless [], shift }
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16         package Wrapper;
17         sub new {
18             my ($class,$proxy) = @_;
19             bless \ $proxy, $class;
20         }
21         sub ref {
22             my $self = shift @_;
23             return $$self;
24         }
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DESCRIPTION

27       This module changes the behavior of the builtin function ref(). If
28       ref() is called on an object that has requested an overloaded ref, the
29       object's "->ref" method will be called and its return value used
30       instead.
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USING

33       To enable this feature for a class, "use UNIVERSAL::ref" in your class.
34       Here is a sample proxy module.
35
36         package Pirate;
37         # Pirate pretends to be a Privateer
38         use UNIVERSAL::ref;
39         sub new { bless {}, shift }
40         sub ref { return 'Privateer' }
41
42       Anywhere you call "ref($obj)" on a "Pirate" object, it will allow
43       "Pirate" to lie and pretend to be something else.
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METHODS

46       import
47           A pragma for ref()-enabling your class. This adds the calling class
48           name to a global list of ref()-enabled classes.
49
50               package YourClass;
51               use UNIVERSAL::ref;
52               sub ref { ... }
53
54       unimport
55           A pragma for ref()-disabling your class. This removes the calling
56           class name from a global list of ref()-enabled classes.
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TODO

59       Currently UNIVERSAL::ref must be installed before any ref() calls that
60       are to be affected.
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62       I think ref() always occurs in an implicit scalar context. There is no
63       accomodation for list context.
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65       UNIVERSAL::ref probably shouldn't allow a module to lie to itself. Or
66       should it?
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ACKNOWLEDGEMENTS

69       ambrus for the excellent idea to overload defined() to allow Perl 5 to
70       have Perl 6's "interesting values of undef."
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72       chromatic for pointing out how utterly broken ref() is. This fix covers
73       its biggest hole.
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AUTHOR

76       Joshua ben Jore - jjore@cpan.org
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LICENSE

79       The standard Artistic / GPL license most other perl code is typically
80       using.
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84perl v5.32.1                      2021-01-27                 UNIVERSAL::ref(3)
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