1constant::tiny(3) User Contributed Perl Documentation constant::tiny(3)
2
6 constant::tiny - Perl pragma to declare constants
7
9 use constant::tiny;
10 use constant PI => 4 * atan2(1, 1);
11 use constant DEBUG => 0;
12 print "Pi equals ", PI, "...\n" if DEBUG;
14
16 This module is a lightweight version of the Perl standard module
17 "constant.pm". Here are the keys differences:
18 · only works on Perl 5.10+ in order to simplify a good part of the
20 code
21 · doesn't support Unicode names; please use the standard
23 "constant.pm" module if you need to create constants with Unicode
24 names
25 · stricter rules about valid names, only allow names with alphanums
27 ("[a-zA-Z0-9]" and underscore ("_"), allowing one optional leading
28 underscore
29 In order to simplify its usage, "constant:tiny" uses the normal
31 "constant" API. The main advatange is that switching your code to
32 "constant::tiny" means simply adding it before the first "use
33 constant". The disadvantage is that, obviously, both modules can't be
34 used at the same time. If the normal "constant" was loaded before
35 "constant::tiny", the latter won't do anything, letting the normal
36 "constant" do the work.
37 Other than this, the usage is (nearly) exactly the same as with the
39 standard "constant" module. For more details, please read constant.
40 Rationale
42 The original reason to write this module was that, starting with
43 version 1.24, "constant" always loaded utf8_heavy.pl, which consumes
44 some memory. Usually, this is not problematic, but in some particular
45 cases (embedded Perl, frequently forked programs a la CGI), the
46 increased memory cost can become a concern.
47 Therefore, this module was written as a alternative solution, with no
49 support for Unicode names, so that programs working in memory
50 constrained environments could have a better control.
51 Funnily enough, the day "constant::tiny" was released on CPAN (the code
53 had been written two months earlier as a proof of concept), Brad
54 Gilbert proposed a patch for "constant" in order to delay loading
55 utf8_heavy.pl until necessary.
56 Therefore "constant::tiny" is less useful (which is good news), but can
58 still address specific needs, if you want to restrict constant names to
59 alphanums only.
60
62 You can find documentation for this module with the perldoc command.
63 perldoc constant::tiny
65 You can also look for information at:
67 · Search CPAN
69 <http://search.cpan.org/dist/constant-tiny/>
71 · Meta CPAN
73 <https://metacpan.org/module/constant::tiny>
75 · RT: CPAN's request tracker (report bugs here)
77 <https://rt.cpan.org/Public/Dist/Display.html?Name=constant-tiny>.
79 · AnnoCPAN: Annotated CPAN documentation
81 <http://annocpan.org/dist/constant-tiny>
83 · CPAN Ratings
85 <http://cpanratings.perl.org/d/constant-tiny>
87
89 Please report any bugs or feature requests to "contant-tiny at
90 rt.cpan.org", or through the web interface at
91 <https://rt.cpan.org/Public/Dist/Display.html?Name=constant-tiny>. I
92 will be notified, and then you'll automatically be notified of progress
93 on your bug as I make changes.
94
96 This module is heavily based on "constant.pm", originaly written by Tom
97 Phoenix, Casey West, Nicholas Clark, Zefram and many other folks from
98 the Perl 5 Porters.
99
101 Sebastien Aperghis-Tramoni "<sebastien at aperghis.net>"
102
104 This module is free software; you can redistribute it or modify it
105 under the same terms as Perl itself.
106perl v5.28.0 2018-07-15 constant::tiny(3)