1 import "StandardLibrary"
3 topologicalSort :: Show a => [(a,a)] -> <Proc> [a]
4 topologicalSort dependencies = MList.freeze answer
6 answer = MList.create ()
8 (?x,?y) <- dependencies => print "RULE 1, x=\(?x), y=\(?y)", Dep ?x ?y, InDegree ?x 0, InDegree ?y 1
9 -InDegree ?x ?a, -InDegree ?x ?b => print "RULE 2, x=\(?x), a=\(?a), b=\(?b)", InDegree ?x (?a + ?b)
10 InDegree ?x ?a => print "InDegree \(?x) \(?a)"
11 InDegree ?x 0 => print "RULE 3, x=\(?x)", AdjustInDegrees ?x, MList.add answer ?x
12 AdjustInDegrees ?x, Dep ?x ?y => print "RULE 4, x=\(?x), y=\(?y)", InDegree ?y (-1)
14 main = topologicalSort [(2,4),(3,7),(7,2),(1,3)]