[CM] Help wanted, making defered/scheduled functions

Kjetil Matheussen k.s.matheussen at gmail.com
Mon Jun 8 10:32:16 PDT 2020

For realtime or semi-realtime usage, you normally store the callbacks
in a binary heap. (https://en.wikipedia.org/wiki/Binary_heap) A binary
heap implemented in an array is both very efficient and quite simple:

You can look at Radium's scheduler, which uses a binary heap, here:


(define (callback)
     (display "500ms later")
     500) ;; I.e. call me again in 500ms. Return #f instead to stop
being called again.

;; start it
(ra:schedule 500 callback)

;; stop it
(ra:remove-schedule callback)

On Mon, Jun 8, 2020 at 6:06 PM Iain Duncan <iainduncanlists at gmail.com> wrote:
> Hi list, I'm hoping someone can give me some brief guidance as I'm sure this is a solved problem in S7 and CM but is beyond my lisp knowledge for how to do it correctly.
> Max/MSP has a scheduler that works with it's global clock. I want to enable something like the following:
> (delay :4n '(my-funct a b c))
> So the delaying side will be implemented in C, and that side will handle converting :4n to the right time according to the max clock and then call *something* in S7 from C at the right time. My question is what the right way to store and then call the delayed function is, given that it might also have anonymous elements
> (delay :4n (list (lambda (x) (...)) :foo :bar))
> Ideally, the way this is done would be compatible with future plans to allow a variant that we can cancel:
> (define future (delay :4n '(my-fun a b c)))
> ... now I can cancel it by doing something to future if need be
> Do I need to do something like have my arg 3 to delay be converted to a function and environment captured and stored with gensym? Is there a known pattern for this that I can look at in the common music sources or other lisp literature? Any help preventing slow wheel re-invention much appreciated!
> thanks
> iain
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