1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
|
package parent;
use strict;
use vars qw($VERSION);
$VERSION = '0.223';
sub import {
my $class = shift;
my $inheritor = caller(0);
if ( @_ and $_[0] eq '-norequire' ) {
shift @_;
} else {
for ( my @filename = @_ ) {
if ( $_ eq $inheritor ) {
warn "Class '$inheritor' tried to inherit from itself\n";
};
s{::|'}{/}g;
require "$_.pm"; # dies if the file is not found
}
}
{
no strict 'refs';
# This is more efficient than push for the new MRO
# at least until the new MRO is fixed
@{"$inheritor\::ISA"} = (@{"$inheritor\::ISA"} , @_);
};
};
"All your base are belong to us"
__END__
=head1 NAME
parent - Establish an ISA relationship with base classes at compile time
=head1 SYNOPSIS
package Baz;
use parent qw(Foo Bar);
=head1 DESCRIPTION
Allows you to both load one or more modules, while setting up inheritance from
those modules at the same time. Mostly similar in effect to
package Baz;
BEGIN {
require Foo;
require Bar;
push @ISA, qw(Foo Bar);
}
By default, every base class needs to live in a file of its own.
If you want to have a subclass and its parent class in the same file, you
can tell C<parent> not to load any modules by using the C<-norequire> switch:
package Foo;
sub exclaim { "I CAN HAS PERL" }
package DoesNotLoadFooBar;
use parent -norequire, 'Foo', 'Bar';
# will not go looking for Foo.pm or Bar.pm
This is equivalent to the following code:
package Foo;
sub exclaim { "I CAN HAS PERL" }
package DoesNotLoadFooBar;
push @DoesNotLoadFooBar::ISA, 'Foo', 'Bar';
This is also helpful for the case where a package lives within
a differently named file:
package MyHash;
use Tie::Hash;
use parent -norequire, 'Tie::StdHash';
This is equivalent to the following code:
package MyHash;
require Tie::Hash;
push @ISA, 'Tie::StdHash';
If you want to load a subclass from a file that C<require> would
not consider an eligible filename (that is, it does not end in
either C<.pm> or C<.pmc>), use the following code:
package MySecondPlugin;
require './plugins/custom.plugin'; # contains Plugin::Custom
use parent -norequire, 'Plugin::Custom';
=head1 DIAGNOSTICS
=over 4
=item Class 'Foo' tried to inherit from itself
Attempting to inherit from yourself generates a warning.
use Foo;
use parent 'Foo';
=back
=head1 HISTORY
This module was forked from L<base> to remove the cruft
that had accumulated in it.
=head1 CAVEATS
=head1 SEE ALSO
L<base>
=head1 AUTHORS AND CONTRIBUTORS
Rafaël Garcia-Suarez, Bart Lateur, Max Maischein, Anno Siegel, Michael Schwern
=head1 MAINTAINER
Max Maischein C< corion@cpan.org >
Copyright (c) 2007 Max Maischein C<< <corion@cpan.org> >>
Based on the idea of C<base.pm>, which was introduced with Perl 5.004_04.
=head1 LICENSE
This module is released under the same terms as Perl itself.
=cut
|
