streams.scm

;; dispatcher is a work in progress haha
(define-syntax dispatcher
  (lambda (x)
    (syntax-case x (else)
      ((d name (case1 do1 ...) ... )
        (with-syntax ( (args (datum->syntax #'d 'args)) )
          #'(define (name m . args)
            (case m
              (case1 do1 ...) ...
                (else (error (symbol->string 'name) "bad operation" m)))))))))

(define stream
  (case-lambda
    (()
      (let ( (into '()) (data 0) )
        (dispatcher stream
          ('connect! (set! into (append into args)))
          ('ping!    (set! data (car args))
                     (for-each (lambda (o) (o 'call!)) into))
          ('reset!   (for-each (lambda (o) (o 'reset!)) into))
          ('call!    (error "stream" "cannot call top-level stream" 'name))
          ('read     data)
          )
        stream))
    ((deps fn)
      (let ( (into '()) (go-on (length deps)) (acc 0) (data 0) )
        (dispatcher stream
          ('connect! (set! into (append into args)))
          ('ping!    (set! data (car args))
                     (for-each (lambda (o) (o 'call!)) into))
          ('reset!   (set! acc 0)
                     (for-each (lambda (o) (o 'reset!)) into))
          ('call!    (set! acc (+ 1 acc))
                     (if (> acc go-on)
                       (error "stream" "bad shenanigans")
                       (when (= acc go-on)
                         (let ( (val (apply fn (map (lambda (s) (s 'read)) deps))) )
                           (stream 'ping! val)))))
          ('read     data)
          )
        (map (lambda (d) (d 'connect! stream)) deps)
        stream))
      ))

use-streams.scm

(define *time* (stream))

(define (clock phase)
  (let ( (acc 0) (state 'low) (half (/ phase 2)) )
    (stream (list *time*)
      (lambda (dt)
        (set! acc (+ acc dt))
        (if (> acc half)
            (begin
              (set! acc 0)
              (case state ('low (set! state 'high) 'rising)
                          ('high (set! state 'low) 'falling)) )
            state)))))

(define c0 (clock 0.25))
(define c1 (clock 0.5))
(define c2 (clock 1))

;; if you have a main loop in your programm that gives you the time between frames (delta-time)
;;   all you have to do is (*time* 'ping! delta-time)
;;   and clocks will run on thier own