/tutorial/backtracking/tiny_prolog/prolog_functor.e

 1expanded class PROLOG_FUNCTOR
 2inherit
 3	COMPARABLE
 4	HASHABLE
 5feature
 6	name: PROLOG_ATOM
 7	arity: INTEGER
 8	infix "<"(other: like Current): BOOLEAN is
 9		do
10			Result := name < other.name
11			if not result and not other.name < name then
12				Result := arity < other.arity
13			end
14		end
15	hash_code: INTEGER is
16		do
17			Result := (name.hash_code * arity) & 0x7FFFFFFF
18		end
19end
20