Commit | Line | Data |
---|---|---|
a0d0e21e | 1 | package less; |
6d39ae0a JJ |
2 | use strict; |
3 | use warnings; | |
f06db76b | 4 | |
7eb1ae03 | 5 | our $VERSION = '0.03'; |
6d39ae0a JJ |
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 | ||
a725df95 RS |
17 | sub stash_name { $_[0] } |
18 | ||
6d39ae0a JJ |
19 | sub of { |
20 | my $class = shift @_; | |
21 | ||
22 | # If no one wants the result, don't bother computing it. | |
23 | return unless defined wantarray; | |
24 | ||
25 | my $hinthash = ( caller 0 )[10]; | |
26 | my %tags; | |
a725df95 | 27 | @tags{ _unpack_tags( $hinthash->{ $class->stash_name } ) } = (); |
6d39ae0a JJ |
28 | |
29 | if (@_) { | |
30 | exists $tags{$_} and return !!1 for @_; | |
31 | return; | |
32 | } | |
33 | else { | |
34 | return keys %tags; | |
35 | } | |
36 | } | |
37 | ||
38 | sub import { | |
39 | my $class = shift @_; | |
12d0f8b2 | 40 | my $stash = $class->stash_name; |
6d39ae0a JJ |
41 | |
42 | @_ = 'please' if not @_; | |
43 | my %tags; | |
12d0f8b2 | 44 | @tags{ _unpack_tags( @_, $^H{ $stash } ) } = (); |
6d39ae0a | 45 | |
12d0f8b2 | 46 | $^H{$stash} = _pack_tags( keys %tags ); |
6d39ae0a JJ |
47 | return; |
48 | } | |
49 | ||
50 | sub unimport { | |
51 | my $class = shift @_; | |
52 | ||
53 | if (@_) { | |
54 | my %tags; | |
55 | @tags{ _unpack_tags( $^H{$class} ) } = (); | |
56 | delete @tags{ _unpack_tags(@_) }; | |
57 | my $new = _pack_tags( keys %tags ); | |
58 | ||
59 | if ( not length $new ) { | |
a725df95 | 60 | delete $^H{ $class->stash_name }; |
6d39ae0a JJ |
61 | } |
62 | else { | |
a725df95 | 63 | $^H{ $class->stash_name } = $new; |
6d39ae0a JJ |
64 | } |
65 | } | |
66 | else { | |
a725df95 | 67 | delete $^H{ $class->stash_name }; |
6d39ae0a JJ |
68 | } |
69 | ||
70 | return; | |
71 | } | |
72 | ||
aa96fdb0 RGS |
73 | 1; |
74 | ||
6d39ae0a | 75 | __END__ |
b75c8c73 | 76 | |
f06db76b AD |
77 | =head1 NAME |
78 | ||
6d39ae0a | 79 | less - perl pragma to request less of something |
cb1a09d0 AD |
80 | |
81 | =head1 SYNOPSIS | |
82 | ||
6d39ae0a | 83 | use less 'CPU'; |
f06db76b AD |
84 | |
85 | =head1 DESCRIPTION | |
86 | ||
6d39ae0a JJ |
87 | This is a user-pragma. If you're very lucky some code you're using |
88 | will know that you asked for less CPU usage or ram or fat or... we | |
89 | just can't know. Consult your documentation on everything you're | |
90 | currently using. | |
91 | ||
92 | For general suggestions, try requesting C<CPU> or C<memory>. | |
f06db76b AD |
93 | |
94 | use less 'memory'; | |
95 | use less 'CPU'; | |
96 | use less 'fat'; | |
97 | ||
6d39ae0a JJ |
98 | If you ask for nothing in particular, you'll be asking for C<less |
99 | 'please'>. | |
100 | ||
101 | use less 'please'; | |
102 | ||
103 | =head1 FOR MODULE AUTHORS | |
104 | ||
105 | L<less> has been in the core as a "joke" module for ages now and it | |
106 | hasn't had any real way to communicating any information to | |
107 | anything. Thanks to Nicholas Clark we have user pragmas (see | |
108 | L<perlpragma>) and now C<less> can do something. | |
109 | ||
110 | You can probably expect your users to be able to guess that they can | |
111 | request less CPU or memory or just "less" overall. | |
112 | ||
113 | If the user didn't specify anything, it's interpreted as having used | |
114 | the C<please> tag. It's up to you to make this useful. | |
115 | ||
116 | # equivalent | |
117 | use less; | |
118 | use less 'please'; | |
119 | ||
120 | =head2 C<< BOOLEAN = less->of( FEATURE ) >> | |
121 | ||
122 | The class method C<< less->of( NAME ) >> returns a boolean to tell you | |
123 | whether your user requested less of something. | |
124 | ||
125 | if ( less->of( 'CPU' ) ) { | |
126 | ... | |
127 | } | |
128 | elsif ( less->of( 'memory' ) ) { | |
129 | ||
130 | } | |
131 | ||
132 | =head2 C<< FEATURES = less->of() >> | |
133 | ||
134 | If you don't ask for any feature, you get the list of features that | |
135 | the user requested you to be nice to. This has the nice side effect | |
136 | that if you don't respect anything in particular then you can just ask | |
137 | for it and use it like a boolean. | |
138 | ||
139 | if ( less->of ) { | |
140 | ... | |
141 | } | |
142 | else { | |
143 | ... | |
144 | } | |
145 | ||
146 | =head1 CAVEATS | |
147 | ||
148 | =over | |
149 | ||
150 | =item This probably does nothing. | |
151 | ||
152 | =item This works only on 5.10+ | |
153 | ||
154 | At least it's backwards compatible in not doing much. | |
155 | ||
156 | =back | |
f06db76b AD |
157 | |
158 | =cut |