C4/Boolean.pm

   1 package C4::Boolean;
   2
   3 #package to handle Boolean values in the parameters table
   4 # Note: This is just a utility module; it should not be instantiated.
   5
   6
   7 # Copyright 2003 Katipo Communications
   8 #
   9 # This file is part of Koha.
  10 #
  11 # Koha is free software; you can redistribute it and/or modify it
  12 # under the terms of the GNU General Public License as published by
  13 # the Free Software Foundation; either version 3 of the License, or
  14 # (at your option) any later version.
  15 #
  16 # Koha is distributed in the hope that it will be useful, but
  17 # WITHOUT ANY WARRANTY; without even the implied warranty of
  18 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  19 # GNU General Public License for more details.
  20 #
  21 # You should have received a copy of the GNU General Public License
  22 # along with Koha; if not, see <http://www.gnu.org/licenses>.
  23
  24 use strict;
  25 use warnings;
  26
  27 use Carp;
  28 use base qw(Exporter);
  29
  30 our    $VERSION = 3.07.00.049;
  31 our    @EXPORT_OK = qw( true_p);
  32
  33 =head1 NAME
  34
  35 C4::Boolean - Convenience function to handle boolean values
  36 in the parameter table
  37
  38 =head1 SYNOPSIS
  39
  40   use C4::Boolean;
  41
  42 =head1 DESCRIPTION
  43
  44 In the parameter table, there are various Boolean values that
  45 variously require a 0/1, no/yes, false/true, or off/on values.
  46 This module aims to provide scripts a means to interpret these
  47 Boolean values in a consistent way which makes common sense.
  48
  49 =head1 FUNCTIONS
  50
  51 =over 2
  52
  53 =cut
  54
  55 use constant INVALID_BOOLEAN_STRING_EXCEPTION =>
  56   q{The given value does not seem to be interpretable as a Boolean value};
  57
  58 our %strings = (
  59    '0'     => 0,    '1'     => 1,    # C
  60                     '-1'    => 1,    # BASIC
  61    'nil'   => 0,    't'     => 1,    # LISP
  62    'false' => 0,    'true'  => 1,    # Pascal
  63    'off'   => 0,    'on'    => 1,
  64    'no'    => 0,    'yes'   => 1,
  65    'n'     => 0,    'y'     => 1,
  66 );
  67
  68 =item true_p
  69
  70     if ( C4::Boolean::true_p(C4::Context->preference("IndependentBranches")) ) {
  71     ...
  72     }
  73
  74 Tries to interpret the passed string as a Boolean value. Returns
  75 the value if the string can be interpreted as such; otherwise an
  76 exception is thrown.
  77
  78 =cut
  79
  80 sub true_p  {
  81     my $x = shift;
  82     my $it;
  83     if (!defined $x || ref $x ) {
  84         carp INVALID_BOOLEAN_STRING_EXCEPTION;
  85         return;
  86     }
  87     $x = lc $x;
  88     $x =~ s/\s//g;
  89     if (defined $strings{$x}) {
  90         $it = $strings{$x};
  91     } else {
  92         carp INVALID_BOOLEAN_STRING_EXCEPTION;
  93     }
  94     return $it;
  95 }
  96
  97 1;
  98 __END__
  99
 100 =back
 101
 102 =head1 AUTHOR
 103
 104 Koha Development Team <http://koha-community.org/>
 105
 106 =cut