Added structure for Regular Expressions, saving work as a backup because of software upgrade.

src/Lexer.cpp

@@ -5,7 +5,8 @@ Lexer::Lexer() {
 }
 
 Lexer::Lexer(std::string inputString) {
-	reader.setString(inputString);
+	input = inputString;
+	currentPosition = 0;
 }
 
 Lexer::~Lexer() {
@@ -13,12 +14,24 @@ Lexer::~Lexer() {
 }
 
 void Lexer::setInput(std::string inputString) {
-	reader.setString(inputString);
+	input = inputString;
+}
+
+void Lexer::addRegexString(std::string regExString) {
+	regExs.push_back(new RegEx(regExString));
 }
 
 Symbol* Lexer::next() {
-	std::string token = reader.word();
-	if (token != "")
-		return new Symbol("\""+token+"\"", true);
-	return new Symbol("$EOF$", false);
+	int longestMatch = 0;
+	RegEx * longestRegEx = NULL;
+	std::string remainingString = input.substr(currentPosition,input.length()-1);
+	for (std::vector<RegEx*>::size_type i = 0; i < regExs.size(); i++) {
+		int currentMatch = regExs[i]->longMatch(remainingString);
+		if (currentMatch > longestMatch) {
+			longestMatch = currentMatch;
+			longestRegEx = regExs[i];
+		}
+	}
+	currentPosition += longestMatch;
+	return new Symbol(longestRegEx->getPattern(), true);
 }

src/RegEx.cpp

@@ -0,0 +1,60 @@
+#include "RegEx.h"
+
+RegEx::RegEx(std::string inPattern) {
+	pattern = inPattern;
+	RegExState* current;
+	begin = new RegExState(pattern.at(0));
+	current = begin;
+	for (int i = 1; i < pattern.length(); i++) {
+		RegExState* next = new RegExState(pattern.at(i));
+		current->addNext(next);
+		current = next;
+	}
+}
+
+RegEx::~RegEx() {
+	//No cleanup necessary
+}
+
+int RegEx::longMatch(std::string stringToMatch) {
+	int lastMatch = 0;
+	currentStates = *(begin->advance(stringToMatch.at(0)));
+	std::vector<RegExState*> nextStates;
+
+	for (int i = 1; i < stringToMatch.size(); i++) {
+		//Go through every current state. Check to see if it is goal, if so update last goal.
+		//Also, add each state's advance to nextStates
+		for (std::vector<RegExState*>::size_type j = 0; j < currentStates.size(); j++) {
+			if (currentStates[j]->isGoal())
+				lastMatch = i-1;
+			std::vector<RegExState*>* addStates = currentStates[j]->advance(stringToMatch.at(i));
+			nextStates.insert(nextStates.end(), addStates->begin(), addStates->end());
+			delete addStates;
+		}
+		//Now, clear our current states and add eaczh one of our addStates if it is not already in current states
+		currentStates.clear();
+		for (std::vector<RegExState*>::size_type j = 0; j < nextStates.size(); j++) {
+			bool inCurrStates = false;
+			for (std::vector<RegExState*>::size_type k = 0; k < currentStates.size(); k++) {
+				if (nextStates[j] == currentStates[i])
+					inCurrStates = true;
+			}
+			if (!inCurrStates)
+				currentStates.push_back(nextStates[j]);
+		}
+		nextStates.clear();
+		//If we can't continue matching, just return our last matched
+		if (currentStates.size() == 0)
+			break;
+	}
+	//Check to see if we match on the last character in the string
+	for (std::vector<RegExState*>::size_type j = 0; j < currentStates.size(); j++) {
+		if (currentStates[j]->isGoal())
+			lastMatch = stringToMatch.size()-1;
+	}
+	return lastMatch;
+}
+
+std::string RegEx::getPattern() {
+	return pattern;
+}

src/RegExState.cpp

@@ -0,0 +1,36 @@
+#include "RegExState.h"
+
+RegExState::RegExState(RegExState* inInnerState) {
+	inner = inInnerState;
+}
+
+RegExState::RegExState(char inCharacter) {
+	character = inCharacter;
+}
+
+RegExState::~RegExState() {
+	//No cleanup necessary
+}
+
+void RegExState::addNext(RegExState* nextState) {
+	nextStates.push_back(nextState);
+}
+
+bool RegExState::characterIs(char inCharacter) {
+	return character == inCharacter;
+}
+
+std::vector<RegExState*>* RegExState::advance(char advanceCharacter) {
+	std::vector<RegExState*>* advanceStates = new std::vector<RegExState*>();
+	for (std::vector<RegExState*>::size_type i = 0; i < nextStates.size(); i++) {
+		if (nextStates[i]->characterIs(advanceCharacter)) 
+			advanceStates->push_back(nextStates[i]);
+	}
+	return advanceStates;
+}
+
+bool RegExState::isGoal() {
+	return inner == NULL && nextStates.size() == 0;
+}
+
+

src/Symbol.cpp

@@ -7,6 +7,13 @@ Symbol::Symbol(std::string name, bool isTerminal) {
 	value = "HAHAHA VALUE";
 }
 
+Symbol::Symbol(std::string name, bool isTerminal, std::string value) {
+	this->name = name;
+	this->terminal = isTerminal;
+	this->subTree = NULL;
+	this->value = value;
+}
+
 Symbol::Symbol(std::string name, bool isTerminal, NodeTree* tree) {
 	this->name = name;
 	this->terminal = isTerminal;