diff --git a/src/lox.cpp b/src/lox.cpp
index 708f316..cef5239 100644
--- a/src/lox.cpp
+++ b/src/lox.cpp
@@ -7,10 +7,12 @@
 #include <string>
 #include <vector>
 
-void print_tokens(std::vector<Token> *list);
-int run_file(std::string file);
+using namespace std;
+
+void print_tokens(vector<Token> *list);
+int run_file(string file);
 void run_prompt(void);
-ScanResult run(std::string source);
+ScanResult run(string source);
 
 int main(int argc, char *argv[]) {
   if (argc > 2) {
@@ -24,9 +26,9 @@ int main(int argc, char *argv[]) {
   return EXIT_SUCCESS;
 }
 
-int run_file(std::string filename) {
-  std::string content;
-  std::ifstream file;
+int run_file(string filename) {
+  string content;
+  ifstream file;
   file.open(filename);
   if (file.is_open()) {
     file >> content;
@@ -40,33 +42,33 @@ int run_file(std::string filename) {
 }
 
 void run_prompt(void) {
-  std::string line;
+  string line;
 
   for (;;) {
-    std::cout << ">";
+    cout << ">";
 
-    std::getline(std::cin, line);
+    getline(cin, line);
 
     ScanResult scan_result = run(line.substr(0, line.length()));
     // print_tokens(&scan_result.token_list);
     if (!scan_result.had_error) {
       Expression *e = (new Parser())->parse(scan_result.token_list);
-      std::cout << e->to_string();
-      std::cout << "\n";
+      cout << e->as_string();
+      cout << "\n";
     }
   }
 }
 
-ScanResult run(std::string source) {
+ScanResult run(string source) {
   Scanner *scanner = new Scanner(source);
   return scanner->scan_tokens();
 }
 
-void print_tokens(std::vector<Token> *list) {
-  for (std::vector<Token>::iterator token = list->begin(); token != list->end();
+void print_tokens(vector<Token> *list) {
+  for (vector<Token>::iterator token = list->begin(); token != list->end();
        ++token) {
-    std::cout << token->to_string() << "(" << token->literal << "), ";
+    cout << token->as_string() << "(" << token->literal << "), ";
   }
 
-  std::cout << "\n";
+  cout << "\n";
 }
diff --git a/src/parser.cpp b/src/parser.cpp
index 08b0415..9992d3d 100644
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -1,13 +1,15 @@
 #include "parser.hpp"
 
+using namespace std;
+
 Expression::~Expression() {}
 
 // class Binary
 ExprType Binary::get_type() { return ExprType::Binary; }
 
-std::string Binary::to_string() {
-  return "(" + token_name(op->tokentype) + " " + left->to_string() + " " +
-         right->to_string() + ")";
+string Binary::as_string() {
+  return "(" + token_name(op->tokentype) + " " + left->as_string() + " " +
+         right->as_string() + ")";
 }
 
 Binary::Binary(Expression *_left, Token *_operator, Expression *_right)
@@ -22,7 +24,7 @@ Binary::~Binary() {
 // class Grouping
 ExprType Grouping::get_type() { return ExprType::Grouping; }
 
-std::string Grouping::to_string() { return "(" + expr->to_string() + ")"; }
+string Grouping::as_string() { return "(" + expr->as_string() + ")"; }
 
 Grouping::Grouping(Expression *_expr) : expr(_expr){};
 
@@ -31,8 +33,8 @@ Grouping::~Grouping() { delete expr; }
 // class Unary
 ExprType Unary::get_type() { return ExprType::Unary; }
 
-std::string Unary::to_string() {
-  return token_name(op->tokentype) + right->to_string();
+string Unary::as_string() {
+  return token_name(op->tokentype) + right->as_string();
 }
 
 Unary::Unary(Token *_operator, Expression *_right)
@@ -44,14 +46,14 @@ Unary::~Unary() {
 }
 
 // class Literal
-std::string Literal::to_string() {
-  std::string text;
+string Literal::as_string() {
+  string text;
   switch (valuetype) {
   case String:
     text = "\"" + value.str + "\"";
     break;
   case Numeric:
-    text = std::to_string(value.numeric);
+    text = to_string(value.numeric);
     break;
   case Boolean:
     text = value.boolean ? "True" : "False";
@@ -63,7 +65,7 @@ std::string Literal::to_string() {
   return text;
 }
 
-Expression *Parser::parse(std::vector<Token> tokenlist) {
+Expression *Parser::parse(vector<Token> tokenlist) {
   tokens = tokenlist;
   current_token = 0;
   return expression();
diff --git a/src/parser.hpp b/src/parser.hpp
index a6b2ec3..cef5174 100644
--- a/src/parser.hpp
+++ b/src/parser.hpp
@@ -7,49 +7,48 @@
 
 enum class ExprType { Binary, Grouping, Unary, Literal, None };
 
+using namespace std;
+
 /// Base class for expressions
 class Expression {
 public:
-  virtual ExprType get_type() = 0;     // abstract, getter for tyoe
-  virtual std::string to_string() = 0; // abstract, string rep for debugging
-  virtual ~Expression();               // destructor
-};
+  virtual ExprType get_type() = 0; // abstract, getter for tyoe
+  virtual string as_string() = 0;  // abstract, string rep for debugging
+  virtual ~Expression();           // destructor
+};                                 // namespace stdclass Expression
 
 /// An expression with two operands
 class Binary : public Expression {
-private:
   Expression *left;
   Token *op;
   Expression *right;
 
 public:
   ExprType get_type() override;
-  std::string to_string() override;
+  string as_string() override;
   Binary(Expression *_left, Token *_operator, Expression *_right);
   ~Binary();
 };
 
 /// An expression between parentheses
 class Grouping : public Expression {
-private:
   Expression *expr;
 
 public:
   ExprType get_type() override;
-  std::string to_string() override;
+  string as_string() override;
   Grouping(Expression *_expr);
   ~Grouping();
 };
 
 /// An expression with one operand (operator is `-`  or `!`)
 class Unary : public Expression {
-private:
   Token *op;
   Expression *right;
 
 public:
   ExprType get_type() override;
-  std::string to_string() override;
+  string as_string() override;
   Unary(Token *_operator, Expression *_right);
   ~Unary();
 };
@@ -67,28 +66,27 @@ public:
   union Value {
     double_t numeric;
     bool boolean;
-    std::string str;
+    string str;
     Void dummy;
 
     Value(double_t _numeric) : numeric(_numeric) {}
     Value(bool _boolean) : boolean(_boolean) {}
-    Value(std::string _str) : str(_str) {}
+    Value(string _str) : str(_str) {}
     Value(Void v) : dummy(v) {}
     ~Value() {}
   } value;
 
   Literal(Void v) : valuetype(ValueType::Nil), value(v){};
   Literal(double_t _numeric) : valuetype(ValueType::Numeric), value(_numeric){};
-  Literal(std::string _str) : valuetype(ValueType::String), value(_str){};
+  Literal(string _str) : valuetype(ValueType::String), value(_str){};
   Literal(bool _boolean) : valuetype(ValueType::Boolean), value(_boolean){};
 
-  std::string to_string() override;
+  string as_string() override;
 };
 
 class Parser {
-private:
-  std::vector<Expression> expressions;
-  std::vector<Token> tokens;
+  vector<Expression> expressions;
+  vector<Token> tokens;
   int current_token;
 
   Token peek() { return tokens[current_token]; };
@@ -116,7 +114,7 @@ private:
 
     for (int i = 0; i < count; i++) {
       Token::Type ttc = va_arg(list, Token::Type);
-      // std::cout << token_name(ttc) << "\n";
+      // cout << token_name(ttc) << "\n";
       if (check(ttc)) {
         advance();
         return true;
@@ -125,16 +123,16 @@ private:
     return false;
   };
 
-  Token *consume(Token::Type typ, std::string message) {
+  Token *consume(Token::Type typ, string message) {
     if (check(typ)) {
       return advance();
     }
     throw error(peek(), message);
   }
 
-  std::runtime_error error(Token token, std::string message) {
-    std::cout << token.to_string() << " " << message;
-    return std::runtime_error(message);
+  runtime_error error(Token token, string message) {
+    cout << token.as_string() << " " << message;
+    return runtime_error(message); // TODO no exceptions
   }
 
   Expression *primary() {
@@ -145,7 +143,7 @@ private:
     if (match(1, Token::Type::NIL))
       return new Literal(new Void());
     if (match(1, Token::Type::NUMBER)) {
-      return new Literal(std::stod(previous()->literal));
+      return new Literal(stod(previous()->literal));
     }
     if (match(1, Token::Type::STRING)) {
       return new Literal(previous()->literal);
@@ -155,11 +153,11 @@ private:
       consume(Token::Type::RIGHT_PAREN, "Expect ')'.");
       return new Grouping(e);
     }
-    throw std::runtime_error("Expected an expression");
+    throw runtime_error("Expected an expression");
   }
 
 public:
-  Expression *parse(std::vector<Token> tokenlist);
+  Expression *parse(vector<Token> tokenlist);
   Expression *unary() {
     if (match(2, Token::BANG, Token::Type::MINUS)) {
       Token *op = previous();
diff --git a/src/scanner.cpp b/src/scanner.cpp
index f910226..005d5f4 100644
--- a/src/scanner.cpp
+++ b/src/scanner.cpp
@@ -6,7 +6,9 @@
 #include <string>
 #include <vector>
 
-static const std::map<std::string, Token::Type> keywords = {
+using namespace std;
+
+static const map<string, Token::Type> keywords = {
     {"and", Token::Type::AND},       {"class", Token::Type::CLASS},
     {"else", Token::Type::ELSE},     {"false", Token::Type::FALSE},
     {"for", Token::Type::FOR},       {"fun", Token::Type::FUN},
@@ -17,9 +19,9 @@ static const std::map<std::string, Token::Type> keywords = {
     {"var", Token::Type::VAR},       {"while", Token::Type::WHILE},
 };
 
-Scanner::Scanner(std::string s)
-    : had_error(false), current_pos(0), start(0), current_line(1), source(s),
-      token_list(std::vector<Token>()) {}
+Scanner::Scanner(string _source)
+    : had_error(false), current_pos(0), start(0), current_line(1),
+      source(_source), token_list(vector<Token>()) {}
 
 ScanResult Scanner::scan_tokens() {
   while (current_pos < source.length()) {
@@ -39,7 +41,7 @@ void Scanner::add_token(Token::Type type) {
   token_list.push_back(token);
 }
 
-void Scanner::add_token(Token::Type type, std::string literal) {
+void Scanner::add_token(Token::Type type, string literal) {
   Token token = Token(type, literal, literal, current_line);
   token_list.push_back(token);
 }
@@ -109,7 +111,7 @@ void Scanner::scan_token() {
     current_line += 1;
     break;
   case '"':
-    string();
+    scan_string();
     break;
   default:
     if (is_digit(c)) {
@@ -128,7 +130,7 @@ void Scanner::identifier() {
     advance();
   }
 
-  std::string text = source.substr(start, current_pos - start);
+  string text = source.substr(start, current_pos - start);
   auto it = keywords.find(text);
   if (it != keywords.end()) {
     add_token(it->second, text);
@@ -149,7 +151,7 @@ void Scanner::number() {
 
 bool Scanner::is_digit(char c) { return c >= '0' && c <= '9'; }
 
-void Scanner::string() {
+void Scanner::scan_string() {
   while (peek() != '"' && !is_at_end()) {
     if (peek() == '\n')
       current_line += 1;
@@ -163,8 +165,8 @@ void Scanner::string() {
 
   advance();
 
-  std::string string = source.substr(start + 1, current_pos - start - 2);
-  add_token(Token::Type::STRING, string);
+  string s = source.substr(start + 1, current_pos - start - 2);
+  add_token(Token::Type::STRING, s);
 }
 
 bool Scanner::match(char expected) {
@@ -200,10 +202,10 @@ bool Scanner::is_alphanumeric(char c) { return is_alpha(c) || is_digit(c); }
 
 bool Scanner::is_at_end(void) { return current_pos >= source.length(); }
 
-void Scanner::error(std::string message) { report("", message); }
+void Scanner::error(string message) { report("", message); }
 
-void Scanner::report(std::string where, std::string message) {
-  std::cout << "*[Line " << current_line << "] Error " << where << " : "
-            << message << "\n";
+void Scanner::report(string where, std::string message) {
+  cout << "*[Line " << current_line << "] Error " << where << " : " << message
+       << "\n";
   had_error = true;
 }
diff --git a/src/scanner.hpp b/src/scanner.hpp
index 90e2f9b..0d44171 100644
--- a/src/scanner.hpp
+++ b/src/scanner.hpp
@@ -5,9 +5,11 @@
 #include <string>
 #include <vector>
 
+using namespace std;
+
 typedef struct {
   bool had_error;
-  std::vector<Token> token_list;
+  vector<Token> token_list;
 } ScanResult;
 
 class Scanner {
@@ -16,26 +18,26 @@ private:
   size_t current_pos;
   int start;
   int current_line;
-  std::string source;
-  std::vector<Token> token_list;
+  string source;
+  vector<Token> token_list;
 
 public:
-  Scanner(std::string s);
+  Scanner(string s);
   ScanResult scan_tokens();
   void add_token(Token::Type type);
-  void add_token(Token::Type type, std::string literal);
+  void add_token(Token::Type type, string literal);
   char advance();
   void scan_token();
   void identifier();
   void number();
   bool is_digit(char c);
-  void string();
+  void scan_string();
   bool match(char expected);
   char peek_next();
   char peek();
   bool is_alpha(char c);
   bool is_alphanumeric(char c);
   bool is_at_end(void);
-  void error(std::string message);
-  void report(std::string where, std::string message);
+  void error(string message);
+  void report(string where, string message);
 };
diff --git a/src/tokens.cpp b/src/tokens.cpp
index 79127eb..2d1df34 100644
--- a/src/tokens.cpp
+++ b/src/tokens.cpp
@@ -1,10 +1,11 @@
 #include "tokens.hpp"
 
-Token::Token(Token::Type _tokentype, std::string _lexeme, std::string _literal,
-             int _line)
+using namespace std;
+
+Token::Token(Token::Type _tokentype, string _lexeme, string _literal, int _line)
     : lexeme(_lexeme), literal(_literal), line(_line), tokentype(_tokentype) {}
 
-std::string token_name(Token::Type tokentype) {
+string token_name(Token::Type tokentype) {
   static const std::string tokens[] = {
       "END_OF_FILE", "LEFT_PAREN", "RIGHT_PAREN",   "LEFT_BRACE", "RIGHT_BRACE",
       "COMMA",       "DOT",        "MINUS",         "PLUS",       "SEMICOLON",
@@ -17,4 +18,4 @@ std::string token_name(Token::Type tokentype) {
   return tokens[(int)tokentype];
 }
 
-std::string Token::to_string() { return token_name(tokentype); }
+std::string Token::as_string() { return token_name(tokentype); }
diff --git a/src/tokens.hpp b/src/tokens.hpp
index 5a1047d..6e3312d 100644
--- a/src/tokens.hpp
+++ b/src/tokens.hpp
@@ -2,10 +2,12 @@
 
 #include <string>
 
+using namespace std;
+
 class Token {
 public:
-  std::string lexeme;
-  std::string literal;
+  string lexeme;
+  string literal;
   int line;
   enum Type {
     END_OF_FILE = 0,
@@ -49,10 +51,10 @@ public:
     WHILE = 38,
   } tokentype;
 
-  std::string to_string();
+  string as_string();
 
   Token(Token::Type _tokentype, std::string _lexeme, std::string _literal,
         int line);
 };
 
-std::string token_name(Token::Type tokentype);
+string token_name(Token::Type tokentype);