Nevermind, it was answered on usenet. ;)
Tayssir
Tayssir John Gabbour wrote:
Hi all,
In cells-test/hello-world.lisp, when running DEF-C-OUTPUT, old-value seems always bound to nil. My understanding is it should be bound to the previous thing the slot was set to. Am I missing something?
Sourcecode and repl output below (on SBCL PPC Darwin 0.9.9):
(use-package :cells) (use-package :utils-kt)
(defmodel computer () ((happen :cell :ephemeral :initform (c-in nil) :accessor happen) (location :cell t :initform (c? (case (^happen) (:leave :away) (:arrive :at-home) (t .cache))) ;; ie, unchanged :accessor location) (response :cell :ephemeral :initform nil :initarg :response :accessor response)))
(flet ((fmt (name new-value old-value-boundp old-value) (format t "~%~A: ~15A (previously ~:[an unbound ~A~;~A~])" name new-value old-value-boundp old-value))) (def-c-output response (self new-value old-value old-value-boundp) (fmt "response" new-value old-value-boundp old-value)) (def-c-output happen (self new-value old-value old-value-boundp) (fmt "happen " new-value old-value-boundp old-value)) (def-c-output location (self new-value old-value old-value-boundp) (fmt "location" new-value old-value-boundp old-value)))
(defun hello-world () (let ((dell (make-be 'computer :response (c? (bwhen (h (happen self)) (if (eql (^location) :at-home) (case h (:knock-knock "who's there?") (:world "hello, world.")) "<silence>")))))) (dotimes (n 2) (setf (happen dell) :knock-knock))
(setf (happen dell) :arrive) (setf (happen dell) :knock-knock) (setf (happen dell) :world) (values)));; At the repl:
CL-USER> (hello-world)
;;; instancing object... happen : NIL (previously an unbound NIL) location: NIL (previously NIL) response: NIL (previously NIL) ;;; instanced object #<COMPUTER {10F59309}>
happen : KNOCK-KNOCK (previously NIL) response: <silence> (previously NIL) happen : KNOCK-KNOCK (previously NIL) response: <silence> (previously NIL) happen : ARRIVE (previously NIL) location: AT-HOME (previously NIL) happen : KNOCK-KNOCK (previously NIL) response: who's there? (previously NIL) happen : WORLD (previously NIL) response: hello, world. (previously NIL)
Thanks, Tayssir _______________________________________________ cells-devel site list cells-devel@common-lisp.net http://common-lisp.net/mailman/listinfo/cells-devel