NAME

       "Object::Pad::FieldAttr::Trigger" - invoke an instance method after a ":writer" accessor

SYNOPSIS

          use Object::Pad;
          use Object::Pad::FieldAttr::Trigger;

          class Label {
             has $title :param :reader :writer :Trigger(redraw);

             method redraw {
                ...
             }
          }

          my $label = Label->new( text => "Something" );

          $label->set_label( "New text here" );
          # $label->redraw is automatically invoked

DESCRIPTION

       This module provides a third-party field attribute for Object::Pad-based classes, which
       declares that a named instance method shall be invoked after a generated ":writer"
       accessor method is called.

       WARNING The ability for Object::Pad to take third-party field attributes is still new and
       highly experimental, and subject to much API change in future. As a result, this module
       should be considered equally experimental.

FIELD ATTRIBUTES

   :Trigger
          has $field :writer :Trigger(NAME) ...;

       Declares that the accessor method generated for the field by the ":writer" attribute will
       invoke the method named by the ":Trigger" attribute, after the new value has been stored
       into the field itself. This method is invoked with no additional arguments, in void
       context.

       Note that this only applies to the generated accessor method. It does not apply to direct
       modifications of the field variable by method code within the class itself.

AUTHOR

       Paul Evans <leonerd@leonerd.org.uk>