=pod

=for comment
DO NOT EDIT. This Pod was generated by Swim v0.1.43.
See http://github.com/ingydotnet/swim-pm#readme

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=head1 NAME

boolean - Boolean support for Perl

=for html
<a href="https://travis-ci.org/ingydotnet/boolean-pm"><img src="https://travis-ci.org/ingydotnet/boolean-pm.png" alt="boolean-pm"></a>

=head1 VERSION

This document describes L<boolean> version B<0.46>.

=head1 SYNOPSIS

    use boolean;

    do &always if true;
    do &never if false;

    do &maybe if boolean($value)->isTrue;

and:

    use boolean ':all';

    $guess = int(rand(2)) % 2 ? true : false;

    do &something if isTrue($guess);
    do &something_else if isFalse($guess);

=head1 DESCRIPTION

Most programming languages have a native C<Boolean> data type. Perl does not.

Perl has a simple and well known Truth System. The following scalar values
are false:

    $false1 = undef;
    $false2 = 0;
    $false3 = 0.0;
    $false4 = '';
    $false5 = '0';

Every other scalar value is true.

This module provides basic Boolean support, by defining two special objects:
C<true> and C<false>.

=head1 RATIONALE

When sharing data between programming languages, it is important to support
the same group of basic types. In Perlish programming languages, these types
include: Hash, Array, String, Number, Null and Boolean. Perl lacks native
Boolean support.

Data interchange modules like YAML and JSON can now C<use boolean> to
encodeI<decode>roundtrip Boolean values.

=head1 FUNCTIONS

This module defines the following functions:

=over

=item C<true>

This function returns a scalar value which will evaluate to true. The value is
a singleton object, meaning there is only one "true" value in a Perl process
at any time. You can check to see whether the value is the "true" object with
the isTrue function described below.

=item C<false>

This function returns a scalar value which will evaluate to false. The value
is a singleton object, meaning there is only one "false" value in a Perl
process at any time. You can check to see whether the value is the "false"
object with the isFalse function described below.

=item C<boolean($scalar)>

Casts the scalar value to a boolean value. If C<$scalar> is true, it returns
C<boolean::true>, otherwise it returns C<boolean::false>.

=item C<isTrue($scalar)>

Returns C<boolean::true> if the scalar passed to it is the C<boolean::true>
object. Returns C<boolean::false> otherwise.

=item C<isFalse($scalar)>

Returns C<boolean::true> if the scalar passed to it is the C<boolean::false>
object. Returns C<boolean::false> otherwise.

=item C<isBoolean($scalar)>

Returns C<boolean::true> if the scalar passed to it is the C<boolean::true> or
C<boolean::false> object. Returns C<boolean::false> otherwise.

=back

=head1 METHODS

Since true and false return objects, you can call methods on them.

=over

=item C<< $boolean->isTrue >>

Same as isTrue($boolean).

=item C<< $boolean->isFalse >>

Same as isFalse($boolean).

=back

=head1 USE OPTIONS

By default this module exports the C<true>, C<false> and C<boolean> functions.

The module also defines these export tags:

=over

=item C<:all>

Exports C<true>, C<false>, C<boolean>, C<isTrue>, C<isFalse>, C<isBoolean>

=back

=head1 DEPRECATIONS

This module offered an export tag, C<-truth>, that overrides the Perl
interpreter's internal values for true and false. This has been found to
corrupt the interpreter in some circumstances. Also, these overrides will no
longer be possible as of Perl 5.22. Therefore, the C<-truth> import tag is
deprecated.

=head1 JSON SUPPORT

JSON::MaybeXS (or less preferably JSON.pm ) will encode Perl data with
boolean.pm values correctly if you use the C<convert_blessed> option:

    use JSON::MaybeXS;
    use boolean -truth;
    my $json = JSON::MaybeXS->new->convert_blessed;
    say $json->encode({false => (0 == 1)});     # Says: '{"false":false}',

=head1 AUTHOR

Ingy döt Net <ingy@cpan.org>

=head1 COPYRIGHT AND LICENSE

Copyright 2007-2016. Ingy döt Net.

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

See L<http://www.perl.com/perl/misc/Artistic.html>

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