Added EOF symbol, making the getTable() saner for ACCEPT and lookahead support in ParseRule

CMakeLists.txt

@@ -4,7 +4,7 @@ project(Kraken)
 
 set( MY_INCLUDES ${PROJECT_SOURCE_DIR}/include)
 
-set( MY_SOURCES main.cpp src/Parser.cpp src/ParseAction.cpp src/ParseRule.cpp src/Symbol.cpp src/StringReader.cpp src/NodeTree.cpp src/State.cpp src/util.cpp )
+set( MY_SOURCES main.cpp src/Parser.cpp src/ParseAction.cpp src/ParseRule.cpp src/Symbol.cpp src/StringReader.cpp src/NodeTree.cpp src/State.cpp src/util.cpp src/Lexer.cpp )
 
 include_directories( ${MY_INCLUDES} )
 

include/Lexer.h

@@ -0,0 +1,20 @@
+#ifndef LEXER_H
+#define LEXER_H
+
+#include "util.h"
+#include "StringReader.h"
+#include "Symbol.h"
+
+#include <string>
+
+class Lexer {
+	public:
+		Lexer();
+		Lexer(std::string inputString);
+		~Lexer();
+		void setInput(std::string inputString);
+		Symbol* next();
+	private:
+		StringReader reader;
+};
+#endif

include/ParseRule.h

@@ -14,7 +14,7 @@
 class ParseRule {
 	public:
 		ParseRule();
-		ParseRule(Symbol* leftHandle, int pointerIndex, std::vector<Symbol*> &rightSide);
+		ParseRule(Symbol* leftHandle, int pointerIndex, std::vector<Symbol*> &rightSide, Symbol* lookahead = NULL);
 		~ParseRule();
 
 		bool const operator==(const ParseRule &other);
@@ -41,6 +41,7 @@ class ParseRule {
 	private:
 		int pointerIndex;
 		Symbol* leftHandle;
+		Symbol* lookahead;
 		std::vector<Symbol*> rightSide;
 
 };

include/Parser.h

@@ -1,16 +1,13 @@
 #ifndef PARSER_H
 #define PARSER_H
 
-#ifndef NULL
-#define NULL 0
-#endif
-
 #include "util.h"
 #include "ParseRule.h"
 #include "ParseAction.h"
 #include "Symbol.h"
 #include "State.h"
 #include "StringReader.h"
+#include "Lexer.h"
 #include "NodeTree.h"
 
 #include <map>
@@ -32,7 +29,7 @@ class Parser {
 		std::string stateSetToString();
 		void addToTable(State* fromState, Symbol* tranSymbol, ParseAction* action);
 		ParseAction* getTable(int state, Symbol* token);
-		NodeTree* parseInput(std::string inputString);
+		NodeTree* parseInput(Lexer* lexer);
 
 		std::string grammerToString();
 		std::string grammerToDOT();

include/util.h

@@ -1,6 +1,10 @@
 #ifndef UTIL_H
 #define UTIL_H
 
+#ifndef NULL
+#define NULL 0
+#endif
+
 #include <string>
 #include <sstream>
 

main.cpp

@@ -1,4 +1,5 @@
 #include "NodeTree.h"
+#include "Lexer.h"
 #include "Parser.h"
 #include <string>
 #include <iostream>
@@ -67,7 +68,7 @@ int main(int argc, char* argv[]) {
 	//outFile << parser.grammerToDOT() << std::endl;
 
 	std::cout << programInputFileString << std::endl;
-	NodeTree* parseTree = parser.parseInput(programInputFileString);
+	NodeTree* parseTree = parser.parseInput(new Lexer(programInputFileString));
 
 	if (parseTree) {
 		std::cout << parseTree->DOTGraphString() << std::endl;

src/Lexer.cpp

@@ -0,0 +1,24 @@
+#include "Lexer.h"
+
+Lexer::Lexer() {
+	//Do nothing
+}
+
+Lexer::Lexer(std::string inputString) {
+	reader.setString(inputString);
+}
+
+Lexer::~Lexer() {
+	//No cleanup necessary
+}
+
+void Lexer::setInput(std::string inputString) {
+	reader.setString(inputString);
+}
+
+Symbol* Lexer::next() {
+	std::string token = reader.word();
+	if (token != "")
+		return new Symbol("\""+token+"\"", true);
+	return new Symbol("$EOF$", false);
+}

src/ParseRule.cpp

@@ -5,10 +5,11 @@ ParseRule::ParseRule() {
 	leftHandle = NULL;
 }
 
-ParseRule::ParseRule(Symbol* leftHandle, int pointerIndex, std::vector<Symbol*> &rightSide) {
+ParseRule::ParseRule(Symbol* leftHandle, int pointerIndex, std::vector<Symbol*> &rightSide, Symbol* lookahead) {
 	this->leftHandle = leftHandle;
 	this->pointerIndex = pointerIndex;
 	this->rightSide = rightSide;
+	this->lookahead = lookahead;
 }
 
 ParseRule::~ParseRule() {

src/Parser.cpp

@@ -162,6 +162,10 @@ std::string Parser::stateSetToString() {
 
 void Parser::addToTable(State* fromState, Symbol* tranSymbol, ParseAction* action) {
 
+	//If this is the first time we're adding to the table, add the EOF character
+	if (symbolIndexVec.size() == 0)
+		symbolIndexVec.push_back(new Symbol("$EOF$", false));
+
 	//find what state num the from state is
 	int stateNum = -1;
 	for (std::vector<State*>::size_type i = 0; i < stateSets.size(); i++) {
@@ -250,15 +254,11 @@ ParseAction* Parser::getTable(int state, Symbol* token) {
 		}
 	}
 
-	//This is the accepting state, as it is the 1th's state's reduction on EOF, which is not in the symbolIndexVec
+	//This is the accepting state, as it is the 1th's state's reduction on EOF, which is 0 in the symbolIndexVec
 	//(This assumes singular goal assignment, a simplification for now)
-	if (state == 1 && symbolIndex == -1)
+	if (state == 1 && symbolIndex == 0)
 		return(new ParseAction(ParseAction::ACCEPT));
 
-	//Quick hack, since there is not right now an EOF token, we'll just check for an unrecognized character (-1) and just apply reductions as if it were the first symbol
-	if (symbolIndex == -1)
-		symbolIndex = 0;
-
 	//If ourside the symbol range of this state (same as NULL), reject
 	if ( symbolIndex >= table[state]->size() )
 		return(new ParseAction(ParseAction::REJECT));
@@ -272,10 +272,8 @@ ParseAction* Parser::getTable(int state, Symbol* token) {
 	return (action);
 }
 
-NodeTree* Parser::parseInput(std::string inputString) {
-	StringReader inputReader;
-	inputReader.setString(inputString);
-	Symbol* token = new Symbol("\""+inputReader.word()+"\"", true);
+NodeTree* Parser::parseInput(Lexer* lexer) {
+	Symbol* token = lexer->next();
 	ParseAction* action;
 
 	stateStack.push(0);
@@ -284,6 +282,7 @@ NodeTree* Parser::parseInput(std::string inputString) {
 	while (true) {
 		std::cout << "In state: " << intToString(stateStack.top()) << std::endl;
 		action = getTable(stateStack.top(), token);
+		std::cout << "Doing ParseAction: " << action->toString() << std::endl;
 		switch (action->action) {
 			case ParseAction::REDUCE:
 			{
@@ -312,7 +311,7 @@ NodeTree* Parser::parseInput(std::string inputString) {
 				std::cout << "Shift " << token->toString() << std::endl;
 
 				symbolStack.push(token);
-				token = new Symbol("\""+inputReader.word()+"\"", true);
+				token = lexer->next();
 				stateStack.push(action->shiftState);
 				break;
 			case ParseAction::ACCEPT:
@@ -321,6 +320,7 @@ NodeTree* Parser::parseInput(std::string inputString) {
 				break;
 			case ParseAction::REJECT:
 				std::cout << "REJECTED!" << std::endl;
+				std::cout << "REJECTED Symbol was " << token->toString() << std::endl;
 				return(NULL);
 				break;
 		}