Piumarta and Warth's Open Objects in R6RS Scheme.
A Scheme implementation of the object model as described in their paper:
Install Racket. $ ./run demo.ss
The basic object model and semantics as described in the paper. Objects at this level are tagged Scheme vectors. Everything above this level is accomplished by (send rcvr op . args).
Send is defined as:
(define (send rcvr op . args) (apply (bind rcvr (vtable rcvr) op) rcvr args))
There are a few additional low-level provisions for extension:
- (bind rcvr vt op) Delegates to (send method 'bind rcvr vt op) for methods that are not Scheme procedures to produce a bound procedure.
- (vtable:add-method ...) Invokes (send method 'method-added-to vt op) for methods that are not Scheme procedures.
- (object:vtable value) Returns a vtable given any Scheme value.
- (object? value) Return true if value is a tagged object vector.
- (send obj '_slot offset) Read slot in tagged object vector.
- (send obj '_slot= offset value) Write slot in tagged object vector.
- (send vtable 'name) vtable name for debugging purposes.
Recursive object writer modeled after the Scheme (write) procedure.
A vtable hierarchy for standard Scheme types. Extends object:vtable with a (cond) on the Scheme type predicates.
Basic class-oriented objects with enumerated slots.
Methods that implement super. Reifies the message being sent using the context of the vtable implementing the method.
- (send method 'bind rcvr vt op)
- (send method 'method-added-to vt op)