#lang liso

;; Read point.liso and regex.liso for uses of this module.

provide:
   proxy
   define-proxy
   apply

;; I have not adapted struct, so it is a bit awkward to use; because
;; prop:procedure maps to (prop procedure), I have to use
;; #"prop:procedure" which is the syntax I chose to represent
;; arbitrary symbols (most Scheme implementations use |xyz|, but I
;; think #"xyz" is better).
struct proxy:
   fn()
   #:property, #"prop:procedure"
   (p, args *) -> ;; used when the proxy is called normally
      proxy-fn(p)(args)

obj msg = ;; this is like apply(obj, msg) = ...
   if proxy?(obj):
      then: proxy-fn(obj)(msg)
      else: racket-apply(obj, msg)

define-syntax define-proxy:
   syntax-rules ():
      define-proxy defn: {pattern => expr, ...} =>
         defn = proxy: match-lambda: {pattern => expr, ...}