From 84566c4ff6aa4ad14e5904a82a55deed75650992 Mon Sep 17 00:00:00 2001
From: Nathan Braswell <nathan@nathanbraswell.com>
Date: Wed, 3 Jul 2013 23:40:36 -0400
Subject: [PATCH] Extended the Regular Expression class to now support * and ?
 as well as +. Next up, perens and alternation

---
 src/RegEx.cpp      | 61 ++++++++++++++++++++++++++++++++++++++++++----
 src/RegExState.cpp | 15 +++++++++---
 2 files changed, 68 insertions(+), 8 deletions(-)

diff --git a/src/RegEx.cpp b/src/RegEx.cpp
index 42dda9a..47a1e56 100644
--- a/src/RegEx.cpp
+++ b/src/RegEx.cpp
@@ -2,14 +2,65 @@
 
 RegEx::RegEx(std::string inPattern) {
 	pattern = inPattern;
-	RegExState* current;
+	std::vector<RegExState*> previousStates;
+	std::vector<RegExState*> currentStates;
 	begin = new RegExState();
-	current = begin;
+	currentStates.push_back(begin);
 	for (int i = 0; i < pattern.length(); i++) {
-		RegExState* next = new RegExState(pattern[i]);
-		current->addNext(next);
-		current = next;
+		switch (pattern[i]) {
+			case '*':
+			{
+				std::cout << "Star at " << i << " in " << pattern << std::endl;
+				for (std::vector<RegExState*>::size_type j = 0; j < currentStates.size(); j++)
+					for (std::vector<RegExState*>::size_type k = 0; k < currentStates.size(); k++)
+						currentStates[j]->addNext(currentStates[k]);
+				//add all previous states to current states to enable skipping over the starred item
+				currentStates.insert(currentStates.end(), previousStates.begin(), previousStates.end());
+			}
+				break;
+			case '+':
+			{
+				std::cout << "Plus at " << i << " in " << pattern << std::endl;
+				//OtherThingy
+				//current->addNext(current);
+				for (std::vector<RegExState*>::size_type j = 0; j < currentStates.size(); j++)
+					for (std::vector<RegExState*>::size_type k = 0; k < currentStates.size(); k++)
+						currentStates[j]->addNext(currentStates[k]);
+			}
+				break;
+			case '?':
+			{
+				std::cout << "Question at " << i << " in " << pattern << std::endl;
+				//add all previous states to current states to enable skipping over the questioned item
+				currentStates.insert(currentStates.end(), previousStates.begin(), previousStates.end());
+			}
+				break;
+			case '|':
+				std::cout << "Alternation at " << i << " in " << pattern << std::endl;
+				//alternation
+				break;
+			case '(':
+				std::cout << "Begin peren at " << i << " in " << pattern << std::endl;
+				//perentheses
+				break;
+			default:
+			{
+				std::cout << "Regular" << std::endl;
+				//Ahh, it's regular
+				RegExState* next = new RegExState(pattern[i]);
+				for (std::vector<RegExState*>::size_type j = 0; j < currentStates.size(); j++)
+					currentStates[j]->addNext(next);
+
+				previousStates.clear();
+				previousStates.insert(previousStates.begin(), currentStates.begin(), currentStates.end());
+				currentStates.clear();
+				currentStates.push_back(next);
+			}
+		}
 	}
+	//last one is goal state
+	for (std::vector<RegExState*>::size_type i = 0; i < currentStates.size(); i++)
+		currentStates[i]->addNext(NULL);
 }
 
 RegEx::~RegEx() {
diff --git a/src/RegExState.cpp b/src/RegExState.cpp
index 2d8b86b..677063f 100644
--- a/src/RegExState.cpp
+++ b/src/RegExState.cpp
@@ -29,21 +29,30 @@ bool RegExState::characterIs(char 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)) 
+		if (nextStates[i] != NULL && nextStates[i]->characterIs(advanceCharacter)) 
 			advanceStates->push_back(nextStates[i]);
 	}
 	return advanceStates;
 }
 
 bool RegExState::isGoal() {
-	return inner == NULL && nextStates.size() == 0;
+	//return inner == NULL && nextStates.size() == 0;
+	for (std::vector<RegExState*>::size_type i = 0; i < nextStates.size(); i++)
+		if (nextStates[i] == NULL)
+			return true;
+	return false;
 }
 
 std::string RegExState::toString() {
 	std::string string = "";
 	string += std::string("\"") + character + "\"";
 	for (std::vector<RegExState*>::size_type i = 0; i < nextStates.size(); i++)
-		string += "->" + nextStates[i]->toString() + " EC ";
+		if (nextStates[i] != this && nextStates[i] != NULL)
+			string += "->" + nextStates[i]->toString() + " EC ";
+		else if (nextStates[i] == NULL)
+			string += "-> GOAL ";
+		else
+			string += "->this";
 	//std::cout << "inner = " << inner << " nextStates size = " << nextStates.size() <<std::endl;
 	return string;
 }