Gtk2::Ex::FormFactory::Rules - Rule checking in a FormFactory framework
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, );
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.
Gtk2::Ex::FormFactory::Rules
Attributes are handled through the common get_ATTR(), set_ATTR() style accessors.
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.
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.
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.
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.", );
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.
Jörn Reder <joern at zyn dot de>
Copyright 2004-2006 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.
1 POD Error
The following errors were encountered while parsing the POD:
Non-ASCII character seen before =encoding in 'Jörn'. Assuming CP1252
To install Gtk2::Ex::FormFactory, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Gtk2::Ex::FormFactory
CPAN shell
perl -MCPAN -e shell install Gtk2::Ex::FormFactory
For more information on module installation, please visit the detailed CPAN module installation guide.