nfa.py

@@ -1,10 +0,0 @@
-from collections import namedtuple
-
-NFA = namedtuple('NFA', ['start', 'accept', 'transitions'])
-
-def copy_nfa(nfa):
-	transitions_copy = {}
-	for from_state in nfa.transitions:
-		transitions_copy[from_state] = nfa.transitions[from_state].copy()
-
-	return NFA(nfa.start, nfa.accept, transitions_copy)

nfa_to_regex.py

@@ -1,7 +1,16 @@
 import enum
+from collections import namedtuple
 
 from regex import lit, concat, bar, star
-from nfa import NFA, copy_nfa
+
+NFA = namedtuple('NFA', ['start', 'accept', 'transitions'])
+
+def copy_nfa(nfa):
+	transitions_copy = {}
+	for from_state in nfa.transitions:
+		transitions_copy[from_state] = nfa.transitions[from_state].copy()
+
+	return NFA(nfa.start, nfa.accept, transitions_copy)
 
 def remove_states(nfa):
 	start, accept, transitions = nfa
@@ -141,19 +150,16 @@ def prettyprint(nfa):
 		print(process_state(from_state) + '\t' + '\t'.join(t))
 
 def main():
-	nfa = NFA('start', ['0'], {
-		'start': {'1': lit('i'), '2': lit('d')},
-		'0': {'1': lit('i'), '2': lit('d')},
-		'1': {'0': lit('d'), '2': lit('i')},
-		'2': {'0': lit('i'), '1': lit('d')}
+	nfa = NFA('start', ['end'], {
+		'start': {'0': lit('s')},
+		'0': {'0': lit('0'), '1': lit('1'), 'end': lit('e'), 'start': lit('r')},
+		'1': {'0': lit('1'), '1': lit('0'), 'start': lit('r')},
+		'end': {'end': lit('e'), 'start': lit('n')}
 	})
 
 	prettyprint(nfa)
 
-	regex = to_regex(nfa)
-
-	print(repr(regex))
-	print(regex)
+	print(to_regex(nfa))
 
 if __name__ == '__main__':
 	main()

regex.py

@@ -81,11 +81,7 @@ def concat(*elements):
 
 	combined = []
 	for element in flattened:
-		if type(element) == Literal and element.text == '':
-			# Drop empty literals
-			continue
-
-		elif len(combined) > 0 and type(combined[-1]) == Literal and type(element) == Literal:
+		if len(combined) > 0 and type(combined[-1]) == Literal and type(element) == Literal:
 			# Combine two literals next to each other
 			# into one literal
 			previous = combined.pop()
@@ -94,11 +90,7 @@ def concat(*elements):
 		else:
 			combined.append(element)
 
-	if len(combined) == 0:
-		# Empty regex, represent with empty literal
-		return lit('')
-
-	elif len(combined) == 1:
+	if len(combined) == 1:
 		element, = combined
 		return element
 	else: