NAME
    constant::boolean - Define TRUE and FALSE constants.

SYNOPSIS
      use constant::boolean;

      use File::Spec;

      sub is_package_exist {
        my ($package) = @_;
        return FALSE unless defined $package;
        foreach my $inc (@INC) {
            my $filename = File::Spec->catfile(
                split( /\//, $inc ), split( /\::/, $package )
            ) . '.pm';
            return TRUE if -f $filename;
        };
        return FALSE;
      };

      no constant::boolean;

DESCRIPTION
    Defines `TRUE' and `FALSE' constants in caller's namespace. You could
    use simple values like empty string or zero for false, or any non-empty
    and non-zero string value as true, but the `TRUE' and `FALSE' constants
    are more descriptive.

    It is virtually the same as:

      # double "not" operator is used for converting scalar to boolean value
      use constant TRUE => !! 1;
      use constant FALSE => !! '';

    The constants exported by `constant::boolean' are not reported by
    Test::Pod::Coverage, so it is more convenient to use this module than to
    define `TRUE' and `FALSE' constants by yourself.

    The constants can be removed from class API with `no constant::boolean'
    pragma or some universal tool like namespace::clean.

AUTHOR
    Piotr Roszatycki <dexter@cpan.org>

LICENSE
    Copyright 2008, 2009 by Piotr Roszatycki <dexter@cpan.org>.

    This program is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.

    See http://www.perl.com/perl/misc/Artistic.html