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authorDavid Thompson <dthompson2@worcester.edu>2013-12-25 19:01:53 -0500
committerDavid Thompson <dthompson2@worcester.edu>2013-12-25 19:01:53 -0500
commitf5243e92122b19aced55b4764471fc54ef8b3f65 (patch)
tree7b529e4130ce1531e09651880c517efd3194dc41
parentb4d1d462da6f4d0d5ff271df3d9c4e0de6eed6d1 (diff)
Turn signal objects into doubly-linked list nodes.
* 2d/signals.scm (signal-connections): Delete it. (signal-inputs, signal-outputs): New procedures.
-rw-r--r--2d/signals.scm57
1 files changed, 35 insertions, 22 deletions
diff --git a/2d/signals.scm b/2d/signals.scm
index 4bf48e8..3d3a92a 100644
--- a/2d/signals.scm
+++ b/2d/signals.scm
@@ -33,7 +33,8 @@
signal-ref
signal-ref-maybe
signal-receiver
- signal-connections
+ signal-inputs
+ signal-outputs
signal-connect!
signal-disconnect!
signal-clear!
@@ -58,23 +59,25 @@
;; programming. State mutation is hidden away and a functional,
;; declarative interface is exposed.
(define-record-type <signal>
- (%make-signal value receiver connections)
+ (%make-signal value receiver inputs outputs)
signal?
(value signal-ref %signal-set!)
(receiver signal-receiver)
- (connections signal-connections %set-signal-connections!))
+ (inputs signal-inputs %set-signal-inputs!)
+ (outputs signal-outputs %set-signal-outputs!))
-(define (make-signal init receiver . connections)
+(define (make-signal init receiver input . inputs)
"Create a new signal with initial value INIT, a procedure RECEIVER
-to transform incoming signal values and zero or more signals to
-connect to."
- (let ((signal (%make-signal init receiver '())))
- (for-each (cut signal-connect! <> signal) connections)
+to transform incoming signal values and one or more signals to connect
+to."
+ (let ((signal (%make-signal init receiver '() '())))
+ (for-each (cut signal-connect! <> signal)
+ (cons input inputs))
signal))
(define (make-root-signal init)
"Create a new root level signal with initial value INIT."
- (%make-signal init #f '()))
+ (%make-signal init #f '() '()))
(define (root-signal? signal)
"Returns true if a signal has no receiver procedure or false
@@ -95,19 +98,27 @@ value will be propagated to SIGNAL-OUT."
(error 'root-signal-error
"Cannot connect to a root signal"
signal-out)
- (%set-signal-connections!
- signal-in
- (cons signal-out (signal-connections signal-in)))))
+ (let ((inputs (signal-inputs signal-out))
+ (outputs (signal-outputs signal-in)))
+ (%set-signal-inputs! signal-out (cons signal-in inputs))
+ (%set-signal-outputs! signal-in (cons signal-out outputs)))))
(define (signal-disconnect! signal-in signal-out)
"Detach SIGNAL-OUT from SIGNAL-IN."
- (%set-signal-connections!
- signal-in
- (delete signal-out (signal-connections signal-in) eq?)))
+ (let ((inputs (signal-inputs signal-out))
+ (outputs (signal-outputs signal-in)))
+ (%set-signal-inputs! signal-out (delete signal-in inputs eq?))
+ (%set-signal-outputs! signal-in (delete signal-out outputs eq?))))
-(define (signal-clear! signal)
- "Disconnect all connections from SIGNAL."
- (%set-signal-connections! signal '()))
+(define (signal-clear-outputs! signal)
+ "Disconnect all output signals from SIGNAL."
+ (for-each (cut signal-disconnect! signal <>)
+ (signal-outputs signal)))
+
+(define (signal-clear-inputs! signal)
+ "Disconnect all inputs signals from SIGNAL."
+ (for-each (cut signal-disconnect! <> signal)
+ (signal-inputs signal)))
(define (signal-receive to from)
"Evaluate the receiver procedure for the signal TO with the signal
@@ -117,7 +128,7 @@ FROM."
(define (signal-propagate signal)
"Notify all connected signals about the current value of SIGNAL."
(for-each (cut signal-receive <> signal)
- (signal-connections signal)))
+ (signal-outputs signal)))
(define (signal-set! signal value)
"Change the current value of SIGNAL to VALUE and propagate SIGNAL to
@@ -145,9 +156,11 @@ the list SIGNALS."
(define (update)
(map signal-ref signals))
- (make-signal (update)
- (lambda (combiner from)
- (signal-set! combiner (update)))))
+ (apply make-signal
+ (update)
+ (lambda (combiner from)
+ (signal-set! combiner (update)))
+ signals))
(define (signal-do proc signal)
"Create a new signal that applies PROC when a new values is received