NAME

Gtk2::Ex::FormFactory::Rules - Rule checking in a FormFactory framework

SYNOPSIS

Gtk2::Ex::FormFactory::Rules->new (
  rules          => Hashref of rules and their implemenation CODEREF's,
  rules_messages => Hashref of the rules' error messages,
  message_format => Format of the "Invalid rules" message thrown
  		      on the GUI,
);

DESCRIPTION

This class implements rule checking in a Gtk2::Ex::FormFactory framework. Each widget can have on or more rules which are checked against the widget's value when the user changes it. This way you can prevent the user from entering illegal data at a high level.

Once the user entered illegal data, the old (legal) value is restored and a corresponding error dialog pops up.

OBJECT HIERARCHY

Gtk2::Ex::FormFactory::Rules

ATTRIBUTES

Attributes are handled through the common get_ATTR(), set_ATTR() style accessors.

rules = HASHREF [optional]

This is a hash of user specified rules. A rule has a name (the hash key) and a CODREF (the hash value) which implements the rule. The CODEREF has the following prototype:

$error = &$CODEREF ($value)

If $value doesn't match the rule, $error is the corresponding error message. $error is undef, if $value is Ok.

rules_messages = HASHREF [optional]

This is a hash of the error messages of the user specified rules. A message should read read as follows:

{field} is an odd value.

When presented to the user, the {field} place holder is replaced with the label of the widget in question.

message_format = SCALAR [optional]

This is the format string for the error message which is displayed to the user. The default is:

Data entered is invalid.\n\n[MESSAGES]\nOld value restored.

where [MESSAGES] is replaced with the actual list of error messages.

BUILTIN RULES

This is a verbatim snapshot of the builtin rules and rules_messages hashes. Please take a look at Gtk2::Ex::FormFactory::Rules' source code for a recent list of builtin rules:

my %RULES = (
  "empty"                     => sub { $_[0] eq ''                    },
  "not-empty"                 => sub { $_[0] ne ''                    },

  "alphanumeric"              => sub { $_[0] =~ /^\w+$/               },
  "identifier"                => sub { $_[0] =~ /^[a-z_]\w*$/i        },
  "no-whitespace"             => sub { $_[0] !~ /\s/                  },

  "integer"                   => sub { $_[0] =~ /^[+-]?\d+$/          },
  "positive-integer"          => sub { $_[0] =~ /^[+]?\d+$/           },
  "negative-integer"          => sub { $_[0] =~ /^-\d+$/              },

  "float"                     => sub { $_[0] =~ /^[+-]?\d+(\.\d+)?$/  },
  "positive-float"            => sub { $_[0] =~ /^[+]?\d+(\.\d+)?$/   },
  "negative-float"            => sub { $_[0] =~ /^-\d+(\.\d+)?$/      },

  "odd"                       => sub {   $_[0] % 2                    },
  "even"                      => sub { !($_[0] % 2)                   },
  
  "file-executable"           => sub { (-f $_[0] && -x $_[0])         },
  "file-writable"             => sub { (-f $_[0] && -w $_[0])         },
  "file-readable"             => sub { (-f $_[0] && -r $_[0])         },
  
  "dir-writable"              => sub { (-d $_[0] && -w $_[0])         },
  "dir-readable"              => sub { (-d $_[0] && -r $_[0])         },

  "parent-dir-writable"       => sub { -w dirname($_[0])              },
  "parent-dir-readable"       => sub { -r dirname($_[0])              },
);

my %RULES_MESSAGES = (
  "empty"                     => "{field} is not empty.",
  "not-empty"                 => "{field} is empty.",

  "alphanumeric"              => "{field} is not alphanumeric.",
  "identifier"                => "{field} is no identifier.",
  "no-whitespace"             => "{field} contains whitespace.",

  "integer"                   => "{field} is no integer.",
  "positive-integer"          => "{field} is no positive integer.",
  "negative-integer"          => "{field} is no negative integer.",

  "float"                     => "{field} is no float.",
  "positive-float"            => "{field} is no positive float.",
  "negative-float"            => "{field} is no negativ float.",

  "odd"                       => "{field} is not odd.",
  "even"                      => "{field} is not even.",
  
  "file-executable"           => "{field} is no file and/or not executable.",
  "file-writable"             => "{field} is no file and/or not writable.",
  "file-readable"             => "{field} is no file and/or not readable.",
  
  "dir-writable"              => "{field} is no directory and/or not writable.",
  "dir-readable"              => "{field} is no directory and/or not readable.",

  "parent-dir-writable"       => "{field} has no writable parent directory.",
  "parent-dir-readable"       => "{field} has no readable parent directory.",
);

AUTHORS

Jörn Reder <joern at zyn dot de>

COPYRIGHT AND LICENSE

Copyright 2004 by Jörn Reder.

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.

This library 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 Library General Public License for more details.

You should have received a copy of the GNU Library General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307 USA.