sunterlib/s48/meta-gc/meta.scm

48 lines
1.5 KiB
Scheme

;; Copyright (C) Johan Ceuppens 2013
;;
;; This program is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 2 of the License, or
;; (at your option) any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this program. If not, see <http://www.gnu.org/licenses/>.
(load "meta-gc.scm")
;; special REPL
;; You can add REPL functions such as ((make-meta) 'cons our-cons)
(define (make-meta)
(let ((*applicants '()))
(define (add-hook symbol fun)
(set! *applicants (append *applicants (list (cons symbol fun)))))
(define (search-applicants msgsymbol)
(do ((l *applicants (cdr *applicants)))
((cond ((null? l)
#f)
((eq? (caar *applicants) msgsymbol)
(cdar *applicants))
))))
;; dynamically bound f- function
(define (post-applicants args)
(if (procedure? f-)
(f- args)))
(define (dispatch msg)
(cond ((eq? msg 'add-hook) add-hook)
((let ((f- (search-applicants msg)))
(if f-
post-applicants)))
(else (display "make-meta : message not understood : ")(display msg)(newline)
)))
dispatch))