def diff_aut(self, automaton, suffix):
"""Renames the automaton's states.
Arguments:
automaton: the automaton to be manipulated.
suffix: the chosen string to be added to the states.
Returns:
An automaton with different names for states.
"""
aux_aut = FiniteAutomaton(
{state + suffix for state in automaton.states},
automaton.alphabet,
{},
automaton.init_state + suffix,
{frozenset([set(state).pop() + suffix])
for state in automaton.final_states})
for state in automaton.transitions:
key = frozenset([set(state).pop() + suffix])
aux_aut.transitions[key] = {}
for symbol in automaton.transitions[state]:
aux_aut.transitions[key][symbol] = set()
for element in automaton.transitions[state][symbol]:
if isinstance(element, str):
element = [element]
aux_aut.transitions[key][symbol].add(
frozenset([set(element).pop() + suffix]))
return aux_aut
def closure_op(self, automatons):
"""Implements the regular expression Kleene star operator.
Arguments:
automatons: a list of automatons to be operated on.
Returns:
An automaton that will accept any non-negative number of
repetitions of its original language.
"""
clsr_aut = FiniteAutomaton(
{"initClsr"}, set(),
{frozenset(["initClsr"]): {automatons[0].epsilon: set()}},
"initClsr", {frozenset(["initClsr"])})
e = clsr_aut.epsilon
for each in automatons:
clsr_aut.states |= each.states
clsr_aut.alphabet |= each.alphabet
clsr_aut.transitions[frozenset(["initClsr"])][e].add(
frozenset([each.init_state]))
clsr_aut.transitions.update(each.transitions)
clsr_aut.final_states |= each.final_states
for state in each.final_states:
try:
clsr_aut.transitions[state][e] = set()
except KeyError:
clsr_aut.transitions[state] = {}
clsr_aut.transitions[state][e] = set()
clsr_aut.transitions[state][e].add(frozenset(["initClsr"]))
return self.add_transitions(clsr_aut)
def rename_aut(self, automaton):
"""Makes the automaton's states' names readable.
Arguments:
automaton: the automaton with confusing names.
Returns:
An automaton with normal names for states.
"""
new_aut = FiniteAutomaton(set(), automaton.alphabet, {}, "", set())
new_states = {}
for i, j in zip(automaton.states, range(len(automaton.states))):
new_states[i] = 'q' + str(j)
for i in new_states:
state = new_states[i]
new_aut.states.add(state)
if frozenset([i]) in automaton.final_states:
final_state = set([new_states[i]])
new_aut.final_states.add(frozenset(final_state))
if i == automaton.init_state:
new_aut.init_state = new_states[i]
for i in automaton.transitions:
new_key = frozenset([new_states[list(set(i))[0]]])
new_aut.transitions[new_key] = {}
for j in automaton.transitions[i]:
new_aut.transitions[new_key][j] = set()
for k in automaton.transitions[i][j]:
if isinstance(k, frozenset):
if len(k) > 1:
to_these_states = {new_states[i] for i in
automaton.transitions[i][j]}
new_aut.transitions[new_key][j] |= to_these_states
else:
to_this_state = set([new_states[list(set(k))[0]]])
new_aut.transitions[new_key][j] |= to_this_state
else:
to_this_state = set([new_states[k]])
new_aut.transitions[new_key][j] |= to_this_state
return new_aut
