diff --git a/regexp.py b/regexp.py
--- a/regexp.py
+++ b/regexp.py
@@ -294,9 +294,9 @@ class Regexp:
 
 class RegexpDFA:
 	def __init__(self, rules, end_states, alphabet_index):
-		self.rules = rules
+		self.rules = rules or [1, 1]
 		self.end_states = end_states
-		self.alphabet_index = alphabet_index
+		self.alphabet_index = alphabet_index or {"": 0}
 
 	@classmethod
 	def create(cls, pattern):
@@ -308,10 +308,9 @@ class RegexpDFA:
 	def match(self, s):
 		st = 0
 		n = len(self.alphabet_index)
-		fail = len(self.rules) // n
 
 		for c in s:
-			if c not in self.alphabet_index or st == fail:
+			if c not in self.alphabet_index:
 				return False
 			key = (st*n + self.alphabet_index[c])
 			st = self.rules[key]