Define signal-count in terms of signal-fold.

* 2d/signals.scm (signal-count): Rewrite.

1 files changed, 3 insertions, 4 deletions

diff --git a/2d/signals.scm b/2d/signals.scm
index 7661434..502aada 100644
--- a/2d/signals.scm
+++ b/2d/signals.scm
@@ -208,10 +208,9 @@ values of SIGNAL using PROC."
 (define (signal-count signal)
   "Create a new signal that increments a counter every time the value
 of SIGNAL changes."
-  (make-signal
-   #:transformer (lambda (value prev from)
-                   (1+ prev))
-   #:connectors (list signal)))
+  ;; Initial value is -1 to compensate for the inital signal update
+  ;; when connecting.
+  (signal-fold (lambda (new old) (1+ old)) -1 signal))
 
 (define (signal-constant constant signal)
   "Create a new signal that emits the value CONSTANT whenever a new