Boolean.pm

package C4::Boolean;

#package to handle Boolean values in the parameters table
# Note: This is just a utility module; it should not be instantiated.


# Copyright 2003 Katipo Communications
#
# This file is part of Koha.
#
# Koha is free software; you can redistribute it and/or modify it under the
# terms of the GNU General Public License as published by the Free Software
# Foundation; either version 2 of the License, or (at your option) any later
# version.
#
# Koha is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
# A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with Koha; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

use strict;
use warnings;

use POSIX;

use vars qw($VERSION @ISA @EXPORT @EXPORT_OK);

BEGIN {
	# set the version for version checking
	$VERSION = 0.02;
	require Exporter;
	@EXPORT = qw(
		&INVALID_BOOLEAN_STRING_EXCEPTION
    );
	@EXPORT_OK = qw(
		true_p
    );
	@ISA = qw(Exporter);
}

=head1 NAME

C4::Boolean - Convenience functions to handle boolean values
in the parameter table

=head1 SYNOPSIS

  use C4::Boolean;

=head1 DESCRIPTION

In the parameter table, there are various Boolean values that
variously require a 0/1, no/yes, false/true, or off/on values.
This module aims to provide scripts a means to interpret these
Boolean values in a consistent way which makes common sense.

=head1 FUNCTIONS

=over 2

=cut

sub INVALID_BOOLEAN_STRING_EXCEPTION ()
    { 'The given value does not seem to be interpretable as a Boolean value' }

use vars qw( %strings );

%strings = (
   '0'     => 0,	'1'     => 1,	# C
   			'-1'    => 1,	# BASIC
   'nil'   => 0,	't'     => 1,	# LISP
   'false' => 0,	'true'  => 1,	# Pascal
   'off'   => 0,	'on'    => 1,
   'no'    => 0,	'yes'   => 1,
   'n'     => 0,	'y'     => 1,
);

=item true_p

    if ( C4::Boolean::true_p(C4::Context->preference("insecure")) ) {
	...
    }

Tries to interpret the passed string as a Boolean value. Returns
the value if the string can be interpreted as such; otherwise an
exception is thrown.

=cut

sub true_p ($) {
    my($x) = @_;
    my $it;
    if (!defined $x || ref($x) ne '') {
	warn INVALID_BOOLEAN_STRING_EXCEPTION;
    }
    $x = lc($x);
    $x =~ s/\s//g;
    if (defined $strings{$x}) {
	$it = $strings{$x};
    } else {
	warn INVALID_BOOLEAN_STRING_EXCEPTION;
    }
    return $it;
}


#---------------------------------

END { }       # module clean-up code here (global destructor)

1;
__END__

=back

=head1 AUTHOR

Koha Development Team <info@koha.org>

=cut