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    @EXPORT_OK = qw( true_p);
  31
  32 =head1 NAME
  33
  34 C4::Boolean - Convenience function to handle boolean values
  35 in the parameter table
  36
  37 =head1 SYNOPSIS
  38
  39   use C4::Boolean;
  40
  41 =head1 DESCRIPTION
  42
  43 In the parameter table, there are various Boolean values that
  44 variously require a 0/1, no/yes, false/true, or off/on values.
  45 This module aims to provide scripts a means to interpret these
  46 Boolean values in a consistent way which makes common sense.
  47
  48 =head1 FUNCTIONS
  49
  50 =over 2
  51
  52 =cut
  53
  54 use constant INVALID_BOOLEAN_STRING_EXCEPTION =>
  55   q{The given value does not seem to be interpretable as a Boolean value};
  56
  57 our %strings = (
  58    '0'     => 0,    '1'     => 1,    # C
  59                     '-1'    => 1,    # BASIC
  60    'nil'   => 0,    't'     => 1,    # LISP
  61    'false' => 0,    'true'  => 1,    # Pascal
  62    'off'   => 0,    'on'    => 1,
  63    'no'    => 0,    'yes'   => 1,
  64    'n'     => 0,    'y'     => 1,
  65 );
  66
  67 =item true_p
  68
  69     if ( C4::Boolean::true_p(C4::Context->preference("IndependentBranches")) ) {
  70     ...
  71     }
  72
  73 Tries to interpret the passed string as a Boolean value. Returns
  74 the value if the string can be interpreted as such; otherwise an
  75 exception is thrown.
  76
  77 =cut
  78
  79 sub true_p  {
  80     my $x = shift;
  81     my $it;
  82     if (!defined $x || ref $x ) {
  83         carp INVALID_BOOLEAN_STRING_EXCEPTION;
  84         return;
  85     }
  86     $x = lc $x;
  87     $x =~ s/\s//g;
  88     if (defined $strings{$x}) {
  89         $it = $strings{$x};
  90     } else {
  91         carp INVALID_BOOLEAN_STRING_EXCEPTION;
  92     }
  93     return $it;
  94 }
  95
  96 1;
  97 __END__
  98
  99 =back
 100
 101 =head1 AUTHOR
 102
 103 Koha Development Team <http://koha-community.org/>
 104
 105 =cut