1constant::boolean(3)  User Contributed Perl Documentation constant::boolean(3)
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NAME

6       constant::boolean - Define TRUE and FALSE constants.
7

SYNOPSIS

9         use constant::boolean;
10
11         use File::Spec;
12
13         sub is_package_exist {
14           my ($package) = @_;
15           return FALSE unless defined $package;
16           foreach my $inc (@INC) {
17               my $filename = File::Spec->catfile(
18                   split( /\//, $inc ), split( /\::/, $package )
19               ) . '.pm';
20               return TRUE if -f $filename;
21           };
22           return FALSE;
23         };
24
25         no constant::boolean;
26

DESCRIPTION

28       Defines "TRUE" and "FALSE" constants in caller's namespace.  You could
29       use simple values like empty string or zero for false, or any non-empty
30       and non-zero string value as true, but the "TRUE" and "FALSE" constants
31       are more descriptive.
32
33       It is virtually the same as:
34
35         # double "not" operator is used for converting scalar to boolean value
36         use constant TRUE => !! 1;
37         use constant FALSE => !! '';
38
39       The constants exported by "constant::boolean" are not reported by
40       Test::Pod::Coverage, so it is more convenient to use this module than
41       to define "TRUE" and "FALSE" constants by yourself.
42
43       The constants can be removed from class API with "no constant::boolean"
44       pragma or some universal tool like namespace::clean.
45

BUGS

47       If you find the bug or want to implement new features, please report it
48       at <http://rt.cpan.org/NoAuth/Bugs.html?Dist=constant-boolean>
49

AUTHOR

51       Piotr Roszatycki <dexter@cpan.org>
52

LICENSE

54       Copyright 2008, 2009 by Piotr Roszatycki <dexter@cpan.org>.
55
56       This program is free software; you can redistribute it and/or modify it
57       under the same terms as Perl itself.
58
59       See <http://www.perl.com/perl/misc/Artistic.html>
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63perl v5.34.0                      2021-07-23              constant::boolean(3)
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