Convenience function to check for 1/0/true/false/on/off/yes/no

[koha.git] / C4 / Boolean.pm

diff --git a/C4/Boolean.pm b/C4/Boolean.pm
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+package C4::Boolean;
+
+# $Id$
+
+#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., 59 Temple Place,
+# Suite 330, Boston, MA  02111-1307 USA
+
+use strict;
+use POSIX;
+require Exporter;
+
+use vars qw($VERSION @ISA @EXPORT @EXPORT_OK);
+
+# set the version for version checking
+$VERSION = 0.01;
+
+=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
+
+@ISA = qw(Exporter);
+@EXPORT = (
+       &INVALID_BOOLEAN_STRING_EXCEPTION
+    );
+
+@EXPORT_OK = qw(
+       true_p
+    );
+
+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
+
+require '/u/acli/lib/cvs.pl';
+sub true_p ($) {
+    my($x) = @_;
+    my $it;
+    if (!defined $x || ref($x) ne '') {
+       die INVALID_BOOLEAN_STRING_EXCEPTION;
+    }
+    $x = lc($x);
+    $x =~ s/\s//g;
+    if (defined $strings{$x}) {
+       $it = $strings{$x};
+    } else {
+       die INVALID_BOOLEAN_STRING_EXCEPTION;
+    }
+    return $it;
+}
+
+
+#---------------------------------
+
+END { }       # module clean-up code here (global destructor)
+
+1;
+__END__
+
+=back
+
+=head1 AUTHOR
+
+Koha Developement team <info@koha.org>
+
+=cut