def match_variable(self, pattern, term):
if can_unify([pattern.qtype, term.qtype]):
if pattern.name in self.assignments:
if self.assignments[pattern.name] == term:
return
raise UnificationError('Cannot match %s with both %s and %s.'
% (pattern, term,
assignments[pattern.name]))
self.assignments[pattern.name] = term
else:
self.fail(pattern, term)
def match_constant(self, pattern, term):
if pattern.name != term.name \
or not can_unify([pattern.qtype, term.qtype]):
self.fail(pattern, term)
