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Gtk2::Ex::FormFactory::Rules.3pm

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 (combined with the locical and operator, except for the special ``or-empty'' rule described beyond) 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/                  },
 
     "zero"                      => sub { $_[0] =~ /^0(\.0*)?$/          },
     "not-zero"                  => sub { $_[0] !~ /^0(\.0*)?$/          },
 
     "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 { (!-d $_[0] && -x $_[0])        },
     "file-writable"             => sub { (!-d $_[0] && -w $_[0])        },
     "file-readable"             => sub { (!-d $_[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])              },
 
     "executable-command"        => "_rule_result",
   );
 
   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.",
 
     "zero"                      => "{field} is not zero",
     "not-zero"                  => "{field} is zero",
 
     "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.",
   );
 
 

Special or-empty rule

There is a special rule called ``or-empty''. If this rule occurs everywhere in the list of rules and the actual value is empty, rule checking quits immediately with a positive result, discarding error states from earlier rules.

Example: [ ``positive-integer'', ``or-empty'' ]

All rules are combined with ``and'', which is usually sufficient, but without this special ``or-empty'' case the common case optionally empty fields can't be done.

AUTHORS

  JA~Xrn Reder <joern at zyn dot de>
 
 

COPYRIGHT AND LICENSE

Copyright 2004-2006 by JA~Xrn 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.