def optional(self):
newStart = State()
newAccept = State()
start = deepcopy(self.start)
accepts = deepcopy(self.accepts)
newStart.addTransition(Transition(epsilon, start))
newStart.addTransition(Transition(epsilon, newAccept))
for a in accepts:
a.setToken(-1)
a.addTransition(Transition(epsilon, newAccept))
newStates = set([newStart, start, newAccept])
for a in accepts:
newStates.add(a)
for s in self.states:
if (s.equals(start) == False):
for a in self.accepts:
if (s.equals(a) == False):
newStates.add(s)
#Free memory
del start
del accepts
return NFA(newStates, NFA.addNewAlphabet(newStates), newStart,
set([newAccept]))
def createBasic(symbol):
e1 = State()
e2 = State()
t1 = Transition(symbol, e2)
e1.addTransition(t1)
states = set([e1, e2])
alphabet = set([symbol])
return NFA(states, alphabet, e1, set([e2]))
def join(self, nfaB):
#Create a deepcopy of start states from both NFAs
startA = deepcopy(self.start)
startB = deepcopy(nfaB.getStart())
#Create a deepcopy of accept states
acceptsA = deepcopy(self.accepts)
acceptsB = deepcopy(nfaB.getAccepts())
#Create new start, accept state and new states set
newStart = State()
newAccept = State()
#Add epsilon transitions to new start state
newStart.addTransition(Transition(epsilon, startA))
newStart.addTransition(Transition(epsilon, startB))
#Add epsilon transition to new accept state
for a in acceptsA:
a.setToken(-1)
a.addTransition(Transition(epsilon, newAccept))
for b in acceptsB:
b.setToken(-1)
b.addTransition(Transition(epsilon, newAccept))
#Add updated "accept" states (no longer accepted), new start and new accept
newStates = set([newStart, newAccept])
for a in acceptsA:
newStates.add(a)
for b in acceptsB:
newStates.add(b)
#Add the remaining states
for e1 in self.states:
for a in self.accepts:
if (e1.equals(a) == False):
newStates.add(e1)
for e2 in nfaB.getStates():
for b in nfaB.getAccepts():
if (e2.equals(b) == False):
newStates.add(e2)
#Free memory
del startA
del startB
del acceptsA
del acceptsB
return NFA(newStates, NFA.addNewAlphabet(newStates), newStart,
set([newAccept]))
def specialJoin(nfas):
newStart = State()
newStates = set([])
accepts = set([])
for nfa in nfas:
start = deepcopy(nfa.getStart())
newStart.addTransition(Transition(epsilon, start))
for e in nfa.getAccepts():
accepts.add(e)
newStates = newStates.union(nfa.getStates())
del start
newStates.add(newStart)
return NFA(newStates, NFA.addNewAlphabet(newStates), newStart, accepts)
def positiveClosure(self):
#Create new start state
newStart = State()
#Create new accept state
newAccept = State()
#Create a deepcopy of actual start and accept state
start = deepcopy(self.start)
accepts = deepcopy(self.accepts)
#Add epsilon transitions
newStart.addTransition(Transition(epsilon, start))
for a in accepts:
a.setToken(-1)
a.addTransition(Transition(epsilon, newAccept))
a.addTransition(Transition(epsilon, start))
#Add updated states on new set
newStates = set([newStart, start, newAccept])
for a in accepts:
newStates.add(a)
#Add remaining states to new set
for s in self.states:
if (s.equals(start) == False):
for a in self.accepts:
if (s.equals(a) == False):
newStates.add(s)
#Free memory
del start
del accepts
return NFA(newStates, NFA.addNewAlphabet(newStates), newStart,
set([newAccept]))
