def dot(self):
s = self.new_state()
e = self.new_state()
nfa = NFA(s)
nfa.add_transition(s, ANY, e)
nfa.add_final_state(e)
return nfa
def char(self, label):
s = self.new_state()
e = self.new_state()
nfa = NFA(s)
nfa.add_transition(s, label, e)
nfa.add_final_state(e)
return nfa
def epsilon(self):
s = self.new_state()
e = self.new_state()
nfa = NFA(s)
nfa.add_transition(s, EPSILON, e)
nfa.add_final_state(e)
return nfa
def charset(self, chars):
s = self.new_state()
e = self.new_state()
nfa = NFA(s)
for char in chars:
nfa.add_transition(s, char, e)
nfa.add_final_state(e)
return e
def concat(self, n1, n2):
s = self.new_state()
m = self.new_state()
e = self.new_state()
nfa = NFA(s)
nfa.insert(s, n1, m)
nfa.insert(m, n2, e)
nfa.add_final_state(e)
return nfa
def star(self, n):
s = self.new_state()
m1 = self.new_state()
m2 = self.new_state()
e = self.new_state()
nfa = NFA(s)
nfa.add_transition(s, EPSILON, m1)
nfa.add_transition(s, EPSILON, e)
nfa.insert(m1, n, m2)
nfa.add_transition(m2, EPSILON, m1)
nfa.add_transition(m2, EPSILON, e)
nfa.add_final_state(e)
return nfa
def choice(self, n1, n2):
s = self.new_state()
s1 = self.new_state()
s2 = self.new_state()
e1 = self.new_state()
e2 = self.new_state()
e = self.new_state()
nfa = NFA(s)
nfa.add_transition(s, EPSILON, s1)
nfa.add_transition(s, EPSILON, s2)
nfa.insert(s1, n1, e1)
nfa.insert(s2, n2, e2)
nfa.add_transition(e1, EPSILON, e)
nfa.add_transition(e2, EPSILON, e)
nfa.add_final_state(e)
return nfa
def glob_automaton(pattern):
nfa = NFA(0)
i = -1
for i, (op, arg) in enumerate(parse_glob(pattern)):
if op is _LIT:
nfa.add_transition(i, arg, i + 1)
elif op is _STAR:
nfa.add_transition(i, ANY, i + 1)
nfa.add_transition(i, EPSILON, i + 1)
nfa.add_transition(i + 1, EPSILON, i)
elif op is _QUEST:
nfa.add_transition(i, ANY, i + 1)
elif op is _RANGE:
for char in arg[0]:
nfa.add_transition(i, char, i + 1)
nfa.add_final_state(i + 1)
return nfa
def levenshtein_automaton(term, k, prefix=0):
nfa = NFA((0, 0))
if prefix:
for i in xrange(prefix):
c = term[i]
nfa.add_transition((i, 0), c, (i + 1, 0))
for i in xrange(prefix, len(term)):
c = term[i]
for e in xrange(k + 1):
# Correct character
nfa.add_transition((i, e), c, (i + 1, e))
if e < k:
# Deletion
nfa.add_transition((i, e), ANY, (i, e + 1))
# Insertion
nfa.add_transition((i, e), EPSILON, (i + 1, e + 1))
# Substitution
nfa.add_transition((i, e), ANY, (i + 1, e + 1))
for e in xrange(k + 1):
if e < k:
nfa.add_transition((len(term), e), ANY, (len(term), e + 1))
nfa.add_final_state((len(term), e))
return nfa