I'm attempting to parse arbitrary strings in Prolog. If the arbitrary string belongs to the language of the grammar, then the code should return true.

s-->ab

a-->[a]a

a-->[a]

b-->[b]b

b-->b

So far, I have...

However, when I have a query such as s([a,a,a,b,b],[]). , prolog returns false when it should be true. I think the code is stuck in infinite recursion, but I am uncertain how to fix it.

c([XIT],X,T c([XIT],X, T) s(Input, []) a(Input,c), b(c, [) a (Input, []) :- C' (Input,a,C), a (C, []) a (Input, []) :- a ([a Input], Input) b(Input, []) :- C' (Input,b,c), b(C, []) b(Input, [I)- c([bIInput], Input) c([XIT],X,T c([XIT],X, T) s(Input, []) a(Input,c), b(c, [) a (Input, []) :- C' (Input,a,C), a (C, []) a (Input, []) :- a ([a Input], Input) b(Input, []) :- C' (Input,b,c), b(C, []) b(Input, [I)- c([bIInput], Input)