Commit | Line | Data |
---|---|---|
a0d0e21e | 1 | package less; |
6d39ae0a JJ |
2 | use strict; |
3 | use warnings; | |
f06db76b | 4 | |
6d39ae0a JJ |
5 | our $VERSION = '0.02'; |
6 | ||
7 | sub _pack_tags { | |
8 | return join ' ', @_; | |
9 | } | |
10 | ||
11 | sub _unpack_tags { | |
12 | return grep { defined and length } | |
13 | map { split ' ' } | |
14 | grep {defined} @_; | |
15 | } | |
16 | ||
17 | sub of { | |
18 | my $class = shift @_; | |
19 | ||
20 | # If no one wants the result, don't bother computing it. | |
21 | return unless defined wantarray; | |
22 | ||
23 | my $hinthash = ( caller 0 )[10]; | |
24 | my %tags; | |
25 | @tags{ _unpack_tags( $hinthash->{$class} ) } = (); | |
26 | ||
27 | if (@_) { | |
28 | exists $tags{$_} and return !!1 for @_; | |
29 | return; | |
30 | } | |
31 | else { | |
32 | return keys %tags; | |
33 | } | |
34 | } | |
35 | ||
36 | sub import { | |
37 | my $class = shift @_; | |
38 | ||
39 | @_ = 'please' if not @_; | |
40 | my %tags; | |
41 | @tags{ _unpack_tags( @_, $^H{$class} ) } = (); | |
42 | ||
43 | $^H{$class} = _pack_tags( keys %tags ); | |
44 | return; | |
45 | } | |
46 | ||
47 | sub unimport { | |
48 | my $class = shift @_; | |
49 | ||
50 | if (@_) { | |
51 | my %tags; | |
52 | @tags{ _unpack_tags( $^H{$class} ) } = (); | |
53 | delete @tags{ _unpack_tags(@_) }; | |
54 | my $new = _pack_tags( keys %tags ); | |
55 | ||
56 | if ( not length $new ) { | |
57 | delete $^H{$class}; | |
58 | } | |
59 | else { | |
60 | $^H{$class} = $new; | |
61 | } | |
62 | } | |
63 | else { | |
64 | delete $^H{$class}; | |
65 | } | |
66 | ||
67 | return; | |
68 | } | |
69 | ||
70 | __END__ | |
b75c8c73 | 71 | |
f06db76b AD |
72 | =head1 NAME |
73 | ||
6d39ae0a | 74 | less - perl pragma to request less of something |
cb1a09d0 AD |
75 | |
76 | =head1 SYNOPSIS | |
77 | ||
6d39ae0a | 78 | use less 'CPU'; |
f06db76b AD |
79 | |
80 | =head1 DESCRIPTION | |
81 | ||
6d39ae0a JJ |
82 | This is a user-pragma. If you're very lucky some code you're using |
83 | will know that you asked for less CPU usage or ram or fat or... we | |
84 | just can't know. Consult your documentation on everything you're | |
85 | currently using. | |
86 | ||
87 | For general suggestions, try requesting C<CPU> or C<memory>. | |
f06db76b AD |
88 | |
89 | use less 'memory'; | |
90 | use less 'CPU'; | |
91 | use less 'fat'; | |
92 | ||
6d39ae0a JJ |
93 | If you ask for nothing in particular, you'll be asking for C<less |
94 | 'please'>. | |
95 | ||
96 | use less 'please'; | |
97 | ||
98 | =head1 FOR MODULE AUTHORS | |
99 | ||
100 | L<less> has been in the core as a "joke" module for ages now and it | |
101 | hasn't had any real way to communicating any information to | |
102 | anything. Thanks to Nicholas Clark we have user pragmas (see | |
103 | L<perlpragma>) and now C<less> can do something. | |
104 | ||
105 | You can probably expect your users to be able to guess that they can | |
106 | request less CPU or memory or just "less" overall. | |
107 | ||
108 | If the user didn't specify anything, it's interpreted as having used | |
109 | the C<please> tag. It's up to you to make this useful. | |
110 | ||
111 | # equivalent | |
112 | use less; | |
113 | use less 'please'; | |
114 | ||
115 | =head2 C<< BOOLEAN = less->of( FEATURE ) >> | |
116 | ||
117 | The class method C<< less->of( NAME ) >> returns a boolean to tell you | |
118 | whether your user requested less of something. | |
119 | ||
120 | if ( less->of( 'CPU' ) ) { | |
121 | ... | |
122 | } | |
123 | elsif ( less->of( 'memory' ) ) { | |
124 | ||
125 | } | |
126 | ||
127 | =head2 C<< FEATURES = less->of() >> | |
128 | ||
129 | If you don't ask for any feature, you get the list of features that | |
130 | the user requested you to be nice to. This has the nice side effect | |
131 | that if you don't respect anything in particular then you can just ask | |
132 | for it and use it like a boolean. | |
133 | ||
134 | if ( less->of ) { | |
135 | ... | |
136 | } | |
137 | else { | |
138 | ... | |
139 | } | |
140 | ||
141 | =head1 CAVEATS | |
142 | ||
143 | =over | |
144 | ||
145 | =item This probably does nothing. | |
146 | ||
147 | =item This works only on 5.10+ | |
148 | ||
149 | At least it's backwards compatible in not doing much. | |
150 | ||
151 | =back | |
f06db76b AD |
152 | |
153 | =cut | |
154 | ||
a0d0e21e | 155 | 1; |