Handle more operators

cclox_src/scanner.cc

@@ -33,6 +33,38 @@ void Scanner::scan_token() {
     case '+': add_token(TokenType::PLUS); break;
     case ';': add_token(TokenType::SEMICOLON); break;
     case '*': add_token(TokenType::STAR); break;
+    case '!':
+      add_token(match('=') ? TokenType::BANG_EQUAL : TokenType::BANG);
+      break;
+    case '=':
+      add_token(match('=') ? TokenType::EQUAL_EQUAL : TokenType::EQUAL);
+      break;
+    case '<':
+      add_token(match('=') ? TokenType::LESS_EQUAL : TokenType::LESS);
+      break;
+    case '>':
+      add_token(match('=') ? TokenType::GREATER_EQUAL : TokenType::GREATER);
+      break;
+    case '/':
+      if (match('/')) {
+        while (peek() != '\n' && !is_at_end()) {
+          advance();
+        }
+      } else {
+        add_token(TokenType::SLASH);
+      }
+
+      break;
+    case ' ':
+    case '\r':
+    case '\t':
+      break;
+    case '\n':
+      ++line;
+      break;
+    case '"':
+      string();
+      break;
     default:
       error_handler.error(line, "Unexpected character.");
       break;
@@ -43,6 +75,23 @@ char Scanner::advance() {
   return code.at(current++);
 }
 
+bool Scanner::match(char expected) {
+  if (is_at_end() || peek() != expected) {
+    return false;
+  }
+
+  current++;
+  return true;
+}
+
+char Scanner::peek() {
+  if (is_at_end()) {
+    return '\0';
+  }
+
+  return code.at(current);
+}
+
 void Scanner::add_token(TokenType type) {
   add_token(type, Object{});
 }
@@ -51,3 +100,22 @@ void Scanner::add_token(TokenType type, Object literal) {
   std::string text = code.substr(start, current - start);
   tokens.push_back(Token(type, text, literal, line));
 }
+
+void Scanner::string() {
+  while (peek() != '"' && !is_at_end()) {
+    if (peek() == '\n') line++;
+    advance();
+  }
+
+  if (is_at_end()) {
+    error_handler.error(line, "Unterminated string.");
+    return;
+  }
+
+  // The closing ".
+  advance();
+
+  // Trim the surrounding quotes.
+  std::string value = code.substr(start + 1, current - 1);
+  add_token(TokenType::STRING, Object(StringObjectType::LITERAL, value));
+}

cclox_src/scanner.hh

@@ -10,8 +10,11 @@ struct Scanner {
   bool is_at_end();
   void scan_token();
   char advance();
+  bool match(char expected);
+  char peek();
   void add_token(TokenType type);
   void add_token(TokenType type, Object literal);
+	void string();
 
   std::string code;
   std::vector<Token> tokens;