Test of the `then` keyword

parse-then-test.red

Red []

idiom: [ [a (x: b) | reset (x: c)] x | reset d ]	; 1
impl: [ a then b | reset c | reset d ]	; 2
;impl: [ a b | reset c | reset d ]	; 2
;impl: [ (f: yes) a (f: no) b | reset if (f) c | reset d ]		; 1
;impl: [ a b | reset not a c | reset d ] 	; 3
;impl: [ not a c | reset a b | reset d ]	; 3
;impl: [ [a fail b] | reset c | reset d ]	; 2, nightly build only
;impl: [ p: a [b | :p reset d |] | reset c | reset d ]	; 1

y: [] n: [not []]
side-eff: []
inp-adv: []
reset: [(clear inp-adv)]
ptrn: func ['w] [ copy/deep reduce [
	reduce [to-paren compose [append side-eff (to-lit-word w)] 'n]
	reduce [to-paren compose [append side-eff (to-lit-word w)] to-paren compose [append inp-adv (to-lit-word w)] 'y]
] ]
? idiom
? impl
print "Results:^/a b c d ^-[input advanced by] [side effects produced by] ..."
foreach a ptrn a [
foreach b ptrn b [
foreach c ptrn c [
foreach d ptrn d [
	set [a? b? c? d?] collect [foreach w [a b c d] [keep last get w]]

	parse [1] impl
	prin [a? b? c? d? pad reduce ["^-impl>" mold inp-adv mold side-eff] 25]
	clear side-eff  clear inp-adv

	parse [1] idiom
	print ["idiom>" mold inp-adv mold side-eff]
	clear side-eff  clear inp-adv
]]]]