TuringMachine allows epsilon transitions

alib/src/automaton/TM/TM.cpp

@@ -95,8 +95,10 @@ void TM::addTransition(const TransitionTM& transition) {
 		throw AutomatonException("State \"" + transition.getFrom().getName() + "\" doesn't exist.");
 	}
-	if (tapeAlphabet.find(transition.getInput()) == tapeAlphabet.end()) {
-		throw AutomatonException("Tape symbol \"" + transition.getInput().getSymbol() + "\" doesn't exist.");
+	if (transition.getInput().getSymbol() != "") {
+		if (tapeAlphabet.find(transition.getInput()) == tapeAlphabet.end()) {
+			throw AutomatonException("Tape symbol \"" + transition.getInput().getSymbol() + "\" doesn't exist.");
+		}
 	}
 	if (states.find(transition.getTo()) == states.end()) {