debugging.lisp

(defpattern sdl-event (type key state)
  `(and (sdl:event-type (type (eq ,type)))
        (sdl::key-key  (key (eq ,key)) ,state)))

(setf (fdefinition 'event-typep) #'sdl:key-down-p)

(sdl:with-init (sdl:sdl-init-video)
  (sdl:window 256 240 :bpp 24 :sw t)
  (sdl:enable-key-repeat 10 10)
  (unwind-protect (let ((event (sdl:new-event))) 
                    (loop
                       with start-time = (get-decoded-time)
                       for current-time =  (get-decoded-time)
                       for event-poll = (sdl-cffi::SDL-Poll-Event event)
                       for event-type = (sdl:event-type event)
                       until (< 5 (- current-time start-time))
                       do 
                         (match event
                           ((key-down-event :key :sdl-key-z state)
                            (format t "You Pressed Z!~%" state)))))
    (sdl:free-event event)))

;; Error
;; The value of KEYWORD is #.(SB-SYS:INT-SAP #X7FFFE002E230), which is not of type KEYWORD.
;;    [Condition of type SIMPLE-TYPE-ERROR]

;; Macro-expansion
;; (BLOCK #:BLOCK1908
;;   (TAGBODY
;;     (RETURN-FROM #:BLOCK1908
;;       (SYMBOL-MACROLET ((OPTIMA::%FAIL (GO #:FAIL1909)))
;;         (IF (KEY-DOWN-EVENTP EVENT)
;;             (LET ((#:G1906 (KEY-DOWN-EVENTKEY EVENT))
;;                   (#:G1907 (KEY-DOWN-EVENTSTATE EVENT)))
;;               (DECLARE (IGNORABLE #:G1906 #:G1907))
;;               (IF (EQ #:G1906 ':SDL-KEY-Z)    <=== error here
;;                   (IF (NULL #:G1907)
;;                       (FORMAT T "You Pressed Z!~%" STATE)
;;                       (GO #:FAIL1909))
;;                   (GO #:FAIL1909)))
;;             (GO #:FAIL1909))))
;;    #:FAIL1909
;;     (RETURN-FROM #:BLOCK1908 NIL)))

the-goal.lisp

;; I'm hoping to replace the cond with a succcint match clause in the lines of
(match event
  (key-down-event :key :sdl-key-z) (format t "You Pressed Z!~%"))

;; My idea is something along the lines of this. The muffles('*') are meant
;; to highlight were I need the match-candidate (arg)
(defpattern key-down-event (&key state scancode key mod mod-key unicode)
  `(when (and (eq :key-down-event (sdl:event-type *event*))
              (eq :sdl-key-z (sdl::key-key *event*) key))))

the-now.lisp

;; A sample 'event-loop'
(sdl:with-init (sdl:sdl-init-video)
    (sdl:window 256 240 :bpp 24 :sw t)
    (sdl:enable-key-repeat 10 10)
    (let ((event (sdl:new-event))) 
      (loop
         with start-time = (get-decoded-time)
         for current-time =  (get-decoded-time)
         for event-poll = (sdl-cffi::SDL-Poll-Event event)
         for event-type = (sdl:event-type event)
         until (< 5 (- current-time start-time))
         do 
           (cond
             ((and (eq :key-down-event event-type) (eq :sdl-key-z (sdl::key-key event)))
              (format t "Z: ~A~%" (sdl::key-state event)))
             ((eq :key-down-event event-type)
              (format t "Down: ~A~%" (sdl::key-state event)))
             ((eq :key-up-event event-type)
              (format t "UP: ~A~%" (sdl::key-state event)))
             ;; ((not (eq :NO-EVENT event-type))  (format t "~A~%" event-type ))
             )
           )
      (sdl:free-event event)))

;; The meat
(defun check-for-input ()
  (let ((event (sdl:new-event)))
    (loop
        ;; Pops the event-queue and binds it to event, return 0 if no pending
        ;; events.
       :for event-poll = (sdl-cffi::SDL-Poll-event event)
       :for event-type = (sdl:event-type event)
       :until (or (= 0 event-poll)
                  (eq :no-event event-type)
                  (eq :quit-event event-type))
       :do
       (when (and (eq :key-down-event event-type) (eq :sdl-key-z (sdl::key-key event)))
         (format t "You Pressed Z!~%")))
    (sdl:free-event event)))