diff --git a/grammar/grammar.y b/grammar/grammar.y
index 1a8401e..bddb269 100644
--- a/grammar/grammar.y
+++ b/grammar/grammar.y
@@ -96,12 +96,12 @@ statements(A) ::= statements(B) statement(C).		{ B->addStatement(C); A = B; }
 %type expr {Expression*}
 expr(A) ::= T_IDENTIFIER(ID).						{ A = new LoadExpression(ID->getText()); }
 expr(A) ::= T_IDENTIFIER(ID) T_ASSIGN expr(E).		{ A = new AssignmentExpression(ID->getText(), E); }
-expr(A) ::= expr(B) T_EQUALS expr(C).				{ A = new BinOpExpression(B, "==", C); }
-expr(A) ::= expr(B) T_LESS expr(C).					{ A = new BinOpExpression(B, "<", C); }
-expr(A) ::= expr(B) T_PLUS expr(C).					{ A = new BinOpExpression(B, "+", C); }
-expr(A) ::= expr(B) T_MINUS expr(C).				{ A = new BinOpExpression(B, "-", C); }
-expr(A) ::= expr(B) T_TIMES expr(C).				{ A = new BinOpExpression(B, "*", C); }
-expr(A) ::= expr(B) T_DIV expr(C).					{ A = new BinOpExpression(B, "/", C); }
+expr(A) ::= expr(B) T_EQUALS expr(C).				{ A = new BinOpExpression(B, OP_EQUALS, C); }
+expr(A) ::= expr(B) T_LESS expr(C).					{ A = new BinOpExpression(B, OP_LESS, C); }
+expr(A) ::= expr(B) T_PLUS expr(C).					{ A = new BinOpExpression(B, OP_PLUS, C); }
+expr(A) ::= expr(B) T_MINUS expr(C).				{ A = new BinOpExpression(B, OP_MINUS, C); }
+expr(A) ::= expr(B) T_TIMES expr(C).				{ A = new BinOpExpression(B, OP_TIMES, C); }
+expr(A) ::= expr(B) T_DIV expr(C).					{ A = new BinOpExpression(B, OP_DIV, C); }
 expr(A) ::= T_CINT(I).								{ A = new ConstantExpression(I->getText()); }
 expr(A) ::= T_TRUE.									{ A = new ConstantExpression("true"); }
 expr(A) ::= T_FALSE.								{ A = new ConstantExpression("false"); }
diff --git a/inc/AST/BinOpExpression.h b/inc/AST/BinOpExpression.h
index a9ed052..779c030 100644
--- a/inc/AST/BinOpExpression.h
+++ b/inc/AST/BinOpExpression.h
@@ -1,15 +1,23 @@
 #ifndef BINOP_H
 #define BINOP_H
 
-#include <string>
 #include "AST/Expression.h"
 
+enum BinOp {
+	OP_EQUALS,
+	OP_LESS,
+	OP_PLUS,
+	OP_MINUS,
+	OP_TIMES,
+	OP_DIV
+};
+
 class BinOpExpression : public Expression {
 public:
-    BinOpExpression(Expression* leftExp ,std::string op, Expression* rightExp);
+	BinOpExpression(Expression* leftExp ,BinOp op, Expression* rightExp);
     virtual ~BinOpExpression();
 
-    std::string getOp();
+	BinOp getOp();
     Expression* getLeftExp();
     Expression* getRightExp();
     virtual void accept(ASTVisitor* visitor);
@@ -17,7 +25,7 @@ public:
 
 
 private:
-    std::string op_;
+	BinOp op_;
     Expression* leftExp_;
     Expression* rightExp_;
 
diff --git a/src/AST/BinOpExpression.cpp b/src/AST/BinOpExpression.cpp
index e2ea9c8..40e05e3 100644
--- a/src/AST/BinOpExpression.cpp
+++ b/src/AST/BinOpExpression.cpp
@@ -1,7 +1,7 @@
 #include "AST/BinOpExpression.h"
 #include "AST/ASTVisitor.h"
 
-BinOpExpression::BinOpExpression(Expression *leftExp, std::string op, Expression *rightExp) :
+BinOpExpression::BinOpExpression(Expression *leftExp, BinOp op, Expression *rightExp) :
     leftExp_(leftExp), op_(op), rightExp_(rightExp) {
 }
 
@@ -9,7 +9,7 @@ BinOpExpression::~BinOpExpression() {
     //
 }
 
-std::string BinOpExpression::getOp() {
+BinOp BinOpExpression::getOp() {
     return op_;
 }
 
diff --git a/src/AST/CodeGenVisitor.cpp b/src/AST/CodeGenVisitor.cpp
index f3fa082..3dffdce 100644
--- a/src/AST/CodeGenVisitor.cpp
+++ b/src/AST/CodeGenVisitor.cpp
@@ -24,26 +24,26 @@ void CodeGenVisitor::visit(BinOpExpression* e) {
 		return;
 	}
 
-//	switch (e->getOp()) {
-//	case "+":
-		value_ = builder_->CreateAdd(lhs, rhs, "addtmp");
-//		break;
-//	case "-":
-//		value_ = builder_->CreateSub(lhs, rhs, "subtmp");
-//		break;
-//	case "*":
-//		value_ = builder_->CreateMul(lhs, rhs, "multmp");
-//		break;
-//	case "/":
-//		value_ = builder_->CreateSDiv(lhs, rhs, "divtmp");
-//		break;
-//	case "==":
-//		value_ = builder_->CreateICmpEQ(lhs, rhs, "eqtmp");
-//		break;
-//	default:
-//		// TODO error
-//		break;
-//	}
+	switch (e->getOp()) {
+	case OP_PLUS:
+	value_ = builder_->CreateAdd(lhs, rhs, "addtmp");
+		break;
+	case OP_MINUS:
+		value_ = builder_->CreateSub(lhs, rhs, "subtmp");
+		break;
+	case OP_TIMES:
+		value_ = builder_->CreateMul(lhs, rhs, "multmp");
+		break;
+	case OP_DIV:
+		value_ = builder_->CreateSDiv(lhs, rhs, "divtmp");
+		break;
+	case OP_EQUALS:
+		value_ = builder_->CreateICmpEQ(lhs, rhs, "eqtmp");
+		break;
+	default:
+		// TODO error
+		break;
+	}
 
 	value_->dump();
 }
diff --git a/src/AST/PrintVisitor.cpp b/src/AST/PrintVisitor.cpp
index ff8377a..af7637d 100644
--- a/src/AST/PrintVisitor.cpp
+++ b/src/AST/PrintVisitor.cpp
@@ -2,6 +2,7 @@
 #include <iostream>
 #include <sstream>
 
+
 PrintVisitor::PrintVisitor() : level_(0) {
 	//
 }
@@ -24,7 +25,33 @@ void PrintVisitor::visit(BinOpExpression* e) {
 	println("BinOpExpression");
 	level_++;
 	std::stringstream ss;
-	ss << "Operator: " << e->getOp();
+	std::string opStr;
+	switch (e->getOp()) {
+	case OP_DIV:
+		opStr = "/";
+		break;
+	case OP_EQUALS:
+		opStr = "==";
+		break;
+	case OP_LESS:
+		opStr = "<";
+		break;
+	case OP_MINUS:
+		opStr = "-";
+		break;
+	case OP_PLUS:
+		opStr = "+";
+		break;
+	case OP_TIMES:
+		opStr = "*";
+		break;
+	default:
+		opStr = "Unknown Op";
+		break;
+	}
+
+
+	ss << "Operator: " << opStr;
 	println(ss.str());
 	println("LHS:");
 	e->getLeftExp()->accept(this);