1Monkey::Patch(3) User Contributed Perl Documentation Monkey::Patch(3)
2
6 Monkey::Patch - Scoped monkeypatching (you can at least play nice)
7
9 version 0.03
10
12 use Monkey::Patch qw(:all);
13 sub some_subroutine {
15 my $pkg = patch_class 'Some::Class' => 'something' => sub {
16 my $original = shift;
17 say "Whee!";
18 $original->(@_);
19 };
20 Some::Class->something(); # says Whee! and does whatever
21 undef $pkg;
22 Some::Class->something(); # no longer says Whee!
23 my $obj = Some::Class->new;
25 my $obj2 = Some::Class->new;
26 my $whoah = patch_object $obj, 'twiddle' => sub {
28 my $original = shift;
29 my $self = shift;
30 say "Whoah!";
31 $self->$original(@_);
32 };
33 $obj->twiddle(); # says Whoah!
35 $obj2->twiddle(); # doesn't
36 $obj->twiddle() # still does
37 undef $whoah;
38 $obj->twiddle(); # but not any more
39
41 The following subroutines are available (either individually or via
42 :all)
43 patch_package (package, subname, code)
45 Wraps "package"'s subroutine named <subname> with your <code>. Your
46 code receives the original subroutine as its first argument, followed
47 by any arguments the subroutine would have normally gotten. You can
48 always call the subroutine ref your received; if there was no
49 subroutine by that name, the coderef will simply do nothing.
50 patch_class (class, methodname, code)
52 Just like "patch_package", except that the @ISA chain is walked when
53 you try to call the original subroutine if there wasn't any subroutine
54 by that name in the package.
55 patch_object (object, methodname, code)
57 Just like "patch_class", except that your code will only get called on
58 the object you pass, not the entire class.
59
61 All the "patch" functions return a handle object. As soon as you lose
62 the value of the handle (by calling in void context, assigning over the
63 variable, undeffing the variable, letting it go out of scope, etc), the
64 monkey patch is unwrapped. You can stack monkeypatches and let go of
65 the handles in any order; they obey a stack discipline, and the most
66 recent valid monkeypatch will always be called. Calling the "original"
67 argument to your wrapper routine will always call the next-most-recent
68 monkeypatched version (or, the original subroutine, of course).
69
71 This magic is only faintly black, but mucking around with the symbol
72 table is not for the faint of heart. Help make this module better by
73 reporting any strange behavior that you see!
74perl v5.34.0 2021-07-22 Monkey::Patch(3)