2 Sub::Prototype::Util - Prototype-related utility routines.
8 use Sub::Prototype::Util qw/flatten recall wrap/;
11 my @args = ( \@a, 1, { d => 2 }, undef, 3 );
13 my @flat = flatten '\@$;$', @args; # ('a', 'b', 'c', 1, { d => 2 })
14 recall 'CORE::push', @args; # @a contains 'a', 'b', 'c', 1, { d => 2 }, undef, 3
15 my $splice = wrap 'CORE::splice', compile => 1;
16 my @b = $splice->(\@a, 4, 2); # @a is now ('a', 'b', 'c', 1, 3) and @b is ({ d => 2 }, undef)
19 Prototypes are evil, but sometimes you just have to bear with them,
20 especially when messing with core functions. This module provides
21 several utilities aimed at facilitating "overloading" of prototyped
24 They all handle 5.10's "_" prototype.
27 "flatten $proto, @args"
28 Flattens the array @args according to the prototype $proto. When @args
29 is what @_ is after calling a subroutine with prototype $proto,
30 "flatten" returns the list of what @_ would have been if there were no
34 Calls the function $name with the prototyped argument list @args. That
35 is, @args should be what @_ is when you define a subroutine with the
36 same prototype as $name. For example,
39 recall 'CORE::push', $a, 1, 2, 3;
41 will call "push @$a, 1, 2, 3" and so fill the arrayref $a with "1, 2,
42 3". This is especially needed for core functions because you can't
45 You can also force the use of a specific prototype. In this case, $name
46 must be a hash reference that holds exactly one key/value pair, the key
47 being the function name and the value the prototpye that should be used
50 recall { 'CORE::push' => '\@$' }, $a, 1, 2, 3; # will only push 1
52 This allows you to recall into "CORE::grep" and "CORE::map" by using the
55 sub mygrep (&@) { recall { 'CORE::grep' => '\&@' }, @_ } # the prototypes are intentionally different
58 Generates a wrapper that does the same thing as "recall", but
59 specialized for a given function. This wrapper can be compiled once for
60 all to avoid calling "eval" at each run (like "recall" does). You can
61 still force the prototype by passing "{ $name => $proto }" as the first
62 argument. Others arguments are seen as key / value pairs and tune the
63 code generated by "wrap". Valid keys are :
66 Specifies the function used in the generated code to test the
67 reference type of scalars. Defaults to 'ref'. You may also want to
68 use "Scalar::Util::reftype".
71 The code executed when a reference of incorrect type is encountered.
72 The result of this snippet is also the result of the generated code,
73 hence it defaults to 'undef'. It's a good place to "croak" or "die"
77 Encloses the code into a "sub { }" block. Default is true.
80 Makes "wrap" compile the code generated and return the resulting
81 code reference. Implies "sub => 1". Be careful that in this case
82 "ref" must be a fully qualified function name. Defaults to false.
84 This is how you make your own "push" that pushes into array references :
87 my $push = wrap 'CORE::push', compile => 1;
88 $push->(\@a, 3 .. 7); # returns 3 + 5 = 8, and @a now contains 0 .. 7
91 The functions "flatten", "recall" and "wrap" are only exported on
92 request, either by providing their name or by the ':funcs' and ':all'
96 Carp, Exporter (core modules since perl 5), Scalar::Util (since 5.7.3).
99 Vincent Pit, "<perl at profvince.com>", <http://www.profvince.com>.
101 You can contact me by mail or on #perl @ FreeNode (vincent or
105 Please report any bugs or feature requests to "bug-sub-prototype-util at
106 rt.cpan.org", or through the web interface at
107 <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Sub-Prototype-Util>. I
108 will be notified, and then you'll automatically be notified of progress
109 on your bug as I make changes.
112 You can find documentation for this module with the perldoc command.
114 perldoc Sub::Prototype::Util
116 Tests code coverage report is available at
117 <http://www.profvince.com/perl/cover/Sub-Prototype-Util>.
120 Copyright 2008 Vincent Pit, all rights reserved.
122 This program is free software; you can redistribute it and/or modify it
123 under the same terms as Perl itself.