1.99.2 Send methods

method ->initialise: name=name, types=[vector], implementation=code|host_method, summary=[string]*, source=[source_location]*, group=[name]*

Create a new method object. Methods come in two flavours: send_method objects for procedures and get_method objects for functions.

Method objects may be associated to a class or to an individual object using the methods class->send_method, class->get_method, object->send_method or object->get_method.

The arguments to method->initialise are:

behaviour<-name	Name of the selector to handle
method<-types	Vector of type objects for arguments
implementation	method<-message implementing the method
method<-summary	Online manual summary description
method<-source	Source-file location of the definition
method<-group	Functional group of the method

Messages to classes are normally associated using the class definition interface implemented by pce_begin_class/[2,3], pce_end_class/0 and various macros defined by these predicates.

The example below defines a move_gesture object that is only active if the window in which the graphical to be moved defines an attribute (get_method) method<-mode that yields the value edit.

...,
new(G, move_gesture),
send(G, send_method,
         send_method(verify, vector(event),
                                 @arg1?window?mode == edit)),
...

The alternative would be to define a new class for move gestures that only operate in windows that are editabe:

:- pce_begin_class(move_if_editable_gesture,
                                   move_gesture).

verify(_G, Ev:event) :->
        "Test if the window is editable"::
        get(Ev?window, mode, edit).

:- pce_end_class.