natural — number is a natural number
Verification of the form field value succeeds if the passed value is a natural number, greater than zero.
Example: Natural number check, displaying a custom error message
FORM_FIELD_NAME=natural "Number is not a natural number"
Up to Interchange 5.5.2, there was a problem in implementation of this order check which allowed negative values and zero to pass as valid.
Interchange 5.9.0:
Source: code/OrderCheck/natural.oc
Lines: 30
# Copyright 2005-2007 Interchange Development Group and others # # This program 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. See the LICENSE file for details. # # $Id: natural.oc,v 1.4 2008-04-28 12:08:38 docelic Exp $ CodeDef natural OrderCheck CodeDef natural Description Natural number CodeDef natural Routine <<EOR sub { my ($ref, $name, $value, $code) = @_; if ($value and $value > 0 and "$value" eq int($value)) { return (1, $name, ''); } $code =~ s/\\/\\\\/g; $code =~ s/^\s*(["'])(.+?)\1$/$2/; if ($code =~ /\S/) { return (0, $name, $code); } else { return (0, $name, 'no natural number'); } } EOR