chomsky.pl

noun(man).
noun(ball).
verb(hit).
verb(took).
article(the).

% Handle splitting sublists
is_cat([], B, C) :-
	B = C.

is_cat([A|AS], BS, [C|CS]) :-
	A = C,
	is_cat(AS, BS, CS).
	

verb_phrase(A) :- 
	[X|Y] = A,
	verb(X), 
	noun_phrase(Y).
	
noun_phrase(A) :-
	[X, Y] = A,
	article(X), 
	noun(Y).
	
sentence(A) :- 
	is_cat(X, Y, A),
	noun_phrase(X), 
	verb_phrase(Y).