parameters.sst

(define p1 (make-parameter 0 #f #f)) => !ignore
(define p2 (make-parameter #undefined #f #f)) => !ignore
(define p3 (make-parameter #undefined #f #f)) => !ignore

(~parameter? p1) => #t
(~parameter? p2) => #t


(~parameter-ref p1) => 0
(~parameter-ref p2 'a) => 'a
(~parameter-ref p3 'x) => 'x

(~parameter-set! p1 1) => #void
(~parameter-set! p2 'b) => #void


(~parameter-ref p1) => 1
(~parameter-ref p2) => 'b
(~parameter-ref p3 'y) => 'y

(~parameter-set! p1 2) => #void
(~parameter-set! p2 'c) => #void

(~parameter-ref p1) => 2
(~parameter-ref p2) => 'c
(~parameter-ref p3 'z) => 'z




(parameterize ()
	(values
		(~parameter-ref p1)
		(~parameter-set! p1 3)
		(~parameter-ref p1)
		(parameterize ()
			(~parameter-set! p1 4)
			(~parameter-ref p1))
		(~parameter-ref p1)
	))
=> #values(2 #void 3 4 3)

(~parameter-ref p1) => 2
(~parameter-ref p2) => 'c
(~parameter-ref p3 'z) => 'z




(parameterize ((p1 3) (p3 #t))
	(values
		(p1)
		(p3)
		(parameterize ((p1 4))
			(p1))
		(parameterize ((p3 #f))
			(p3))
		(p1)
		(p3)
	))
=> #values(3 #t 4 #f 3 #t)

(~parameter-ref p1) => 2
(~parameter-ref p2) => 'c
(~parameter-ref p3 'z) => 'z