Data commit

Task/Amb/Red/amb.red

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+Red ["Amb operator"]
+
+findblock: function [
+	blk [block!]
+][
+	foreach w blk [
+		if all [word? w block? get w] [return w]
+		if block? w [findblock w]
+	]
+]
+
+amb: function [
+	cond [block!]
+][
+	either b: findblock cond [
+		foreach a get b [
+			cond2: replace/all/deep copy/deep cond b a
+			if amb cond2 [set b a return true]]	
+	][do cond]	
+]
+
+; examples
+
+x: [1 2 3 4]
+y: [4 5 6]
+z: [5 2]
+print amb [x * y * z = 8]
+print [x y z]
+
+a: ["the" "that" "a"]
+b: ["frog" "elephant" "thing"]
+c: ["walked" "treaded" "grows"]
+d: ["slowly" "quickly"]
+print amb [
+	all [
+		equal? last a first b
+		equal? last b first c
+		equal? last c first d
+	]
+]
+print [a b c d]