NAME

       HTML::Widget::Constraint::CallbackOnce - CallbackOnce Constraint

SYNOPSIS

           my $c = $widget->constraint( 'CallbackOnce', 'foo', 'bar' )->callback(
             sub {
               my ($foo, $bar) = @_;
               return 1 if $foo == $bar * 2;
           });

DESCRIPTION

       A callback constraint which will only be run once for each call of "process" in
       HTML::Widget.

METHODS

   callback
   cb
       Arguments: \&callback

       Requires a subroutine reference used for validation, which will be passed a list of values
       corresponding to the constraint names.

       "cb" is provided as an alias to "callback".

   process
       Overrides "process" in HTML::Widget::Constraint to ensure "validate" is only called once
       for each call of "validate".

   render_errors
       Arguments: @names

       A list of element names for which an error should be displayed.

       If this is not set, the default behaviour is for the error to be displayed for all of the
       Constraint's named elements.

   validate
       perform the actual validation.

AUTHOR

       Carl Franks "cfranks@cpan.org"

LICENSE

       This library is free software, you can redistribute it and/or modify it under the same
       terms as Perl itself.