def _validate_final_states(self):
"""Raise an error if any final states are invalid."""
invalid_states = self.final_states - self.states
if invalid_states:
raise exceptions.InvalidStateError(
'final states are not valid ({})'.format(
', '.join(str(state) for state in invalid_states)))
def _validate_transition_end_states(self, start_state, paths):
"""Raise an error if transition end states are invalid."""
for end_state in paths.values():
if end_state not in self.states:
raise exceptions.InvalidStateError(
'end state {} for transition on {} is not valid'.format(
end_state, start_state))
def _validate_transition_result(self, result):
result_state, result_symbol, result_direction = result
if result_state not in self.states:
raise exceptions.InvalidStateError(
'result state is not valid ({})'.format(result_state))
if result_symbol not in self.tape_symbols:
raise exceptions.InvalidSymbolError(
'result symbol is not valid ({})'.format(result_symbol))
self._validate_transition_result_direction(result_direction)
def _validate_initial_state(self):
"""Raise an error if the initial state is invalid."""
if self.initial_state not in self.states:
raise exceptions.InvalidStateError(
'{} is not a valid initial state'.format(self.initial_state))
def _validate_transition_state(self, transition_state):
if transition_state not in self.states:
raise exceptions.InvalidStateError(
'transition state is not valid ({})'.format(transition_state))
