syndicate-2017/racket/syndicate/drivers/timestate.rkt

22 lines
746 B
Racket

#lang syndicate/actor
(provide (struct-out later-than)
stop-when-timeout)
(require/activate syndicate/drivers/timer)
(struct later-than (msecs) #:prefab)
(actor #:name 'drivers/timestate
(during (observe (later-than $msecs))
(define timer-id (gensym 'timestate))
(field [expired? #f])
(on-start (send! (set-timer timer-id msecs 'absolute)))
(on (message (timer-expired timer-id _)) (expired? #t))
(assert #:when (expired?) (later-than msecs))))
(define-syntax-rule (stop-when-timeout relative-msecs body ...)
(let ((timer-id (gensym 'timeout)))
(on-start (send! (set-timer timer-id relative-msecs 'relative)))
(stop-when (message (timer-expired timer-id _)) body ...)))