diff options
| -rw-r--r-- | sly/signal.scm | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/sly/signal.scm b/sly/signal.scm index a3e79c4..9780b1c 100644 --- a/sly/signal.scm +++ b/sly/signal.scm @@ -26,6 +26,7 @@ #:use-module (srfi srfi-9) #:use-module (srfi srfi-26) #:use-module (sly agenda) + #:use-module (sly coroutine) #:export (signal? make-signal define-signal @@ -48,7 +49,8 @@ signal-tap signal-sample signal-delay - signal-throttle)) + signal-throttle + signal-generator)) ;;; ;;; Signals @@ -349,3 +351,25 @@ ticks of the current agenda." (%signal-set! self value) (set! last-time (agenda-time))))) (list signal))) + +(define-syntax-parameter yield + (lambda (form) + (syntax-violation 'yield + "yield used outside of a signal-generator form" + form))) + +(define-syntax-rule (signal-generator body ...) + (let ((signal (make-signal #f))) + (define (handler k value) + (signal-set! signal value) + (call-with-prompt 'signal-generator k handler)) + (coroutine + (call-with-prompt + 'signal-generator + (syntax-parameterize + ((yield (syntax-rules () + ((_ exp) + (abort-to-prompt 'signal-generator exp))))) + (lambda () body ...)) + handler)) + signal)) |