TODO

https://github.com/johnstonskj/behavior/tree/master

You should look at how you might parse SCTOML and give a state machine.
(State Chart XML)

I think that for the *tick* event, you might be able to do this with the (getitimer)

https://www.gnu.org/software/guile/manual/html_node/Signals.html
(setitimer ITIMER_REAL
           5 500000     ;; Raise SIGALRM every 5.5 seconds
           2 0)         ;; with the first SIGALRM in 2 seconds
This would then be handled in a SIGALRM handler:
(define (stuff signum)
    (when (= signum SIGALRM)
        (display "caught alarm\n")))

(sigaction SIGALRM stuff)

I guess for the operation of delayed things, you have to set the granularity of
the tick timer to be the LCM of the two intervals? (Or something close to it).