diff --git a/src/lexer.l b/src/lexer.l
index f7fb4db..162a4bc 100644
--- a/src/lexer.l
+++ b/src/lexer.l
@@ -1,5 +1,6 @@
 %{
 #include <stack>
+#include <string>
 #include "syntax.h"
 #include "parser.h"
 using namespace std;
@@ -36,12 +37,12 @@ if (s.top() == yyleng) {
 }
 	       			}
 #[^\n]*					// Eat comments
-\"[^"]*\"				yylval.sym = yytext; return STRING;
+\"[^"]*\"				yylval.sym = new string(yytext); return STRING;
 if					return IF;
 else					return ELSE;
 elif 					return ELIF;
 {digit}+|{digit}*\.{digit}+		yylval.num = atof(yytext); return NUM;
-{letter}({letter}|{digit}|[?.-])*	yylval.sym = yytext; return ID;
+{letter}({letter}|{digit}|[?.-])*	yylval.sym = new string(yytext); return ID;
 "<-"					return GETS;
 "->"					return MAPS;
 ".."					return CAT;
diff --git a/src/parser.y b/src/parser.y
index 0dcc3bb..371c9b3 100644
--- a/src/parser.y
+++ b/src/parser.y
@@ -1,5 +1,7 @@
 %{
+
 #include <cstdio>
+#include <string>
 
 #include "syntax.h"
 
@@ -7,13 +9,14 @@ using namespace std;
 
 int yylex();
 void yyerror(const char* p) { fprintf(stderr, p); }
+
 %}
 
 %define parse.trace
 
 %union {
        float num;
-       char *sym;
+       std::string *sym;
        Node *expr;
        NodeList *exprlist;
 }
@@ -29,7 +32,7 @@ void yyerror(const char* p) { fprintf(stderr, p); }
 %right GETS
 %left CAT
 %left '+' '-'
-%left '/' '*'n
+%left '/' '*'
 %left MAPS
 
 %nterm <expr> expr
@@ -62,7 +65,7 @@ param:	 	ID | '_' | // null production;
 funcall: 	ID '(' exprlist ')' { print_expression_list($3); }
 exprlist:	exprlist ',' expr { $1 -> push_back($3); $$ = $1; }
 		| expr { $$ = new NodeList(); $$ -> push_back($1); }
-		| { $$ = NULL; } // null production;
+		| { $$ = new NodeList(); } // null production;
 
 conditional: 	IF expr block elifs
 		| IF expr block elifs ELSE block;
diff --git a/src/syntax.cpp b/src/syntax.cpp
index 2272fb2..a6733d4 100644
--- a/src/syntax.cpp
+++ b/src/syntax.cpp
@@ -6,12 +6,12 @@
 
 using namespace std;
 
-IdNode::IdNode(char * id) {
-  this->id = string(id);
+IdNode::IdNode(string *id) {
+  this->id = id;
 }
 
 void IdNode::display() {
-  cout << id;
+  cout << *id;
 }
 
 NumNode::NumNode(float num) {
@@ -22,8 +22,8 @@ void NumNode::display() {
   
 }
 
-StringNode::StringNode(char *str) {
-  this->stringVal = str;
+StringNode::StringNode(string* stringVal) {
+  this->stringVal = stringVal;
 }
 
 void StringNode::display() {
diff --git a/src/syntax.h b/src/syntax.h
index fffa45a..fe75316 100644
--- a/src/syntax.h
+++ b/src/syntax.h
@@ -11,9 +11,9 @@ public:
 
 class IdNode : public Node {
 private:
-  std::string id;
+  std::string *id;
 public:
-  IdNode(char*);
+  IdNode(std::string*);
   virtual void display();
 };
 
@@ -27,9 +27,9 @@ public:
 
 class StringNode : public Node {
 private:
-  char* stringVal;
+  std::string* stringVal;
 public:
-  StringNode(char*);
+  StringNode(std::string*);
   virtual void display();
 };