Add expression evaluation

cclox_src/scanner/object.cc

@@ -21,6 +21,35 @@ std::string Object::to_string() {
   }
 }
 
+bool Object::operator==(const Object &other) {
+  if (type != other.type) {
+    return false;
+  }
+
+  switch (type) {
+    case ObjectType::NIL: return true;
+    case ObjectType::BOOL: {
+      bool left  = std::get<bool>(value);
+      bool right = std::get<bool>(other.value);
+
+      return left == right;
+    }
+    case ObjectType::IDENTIFIER:
+    case ObjectType::STRING_LIT: {
+      std::string left  = std::get<std::string>(value);
+      std::string right = std::get<std::string>(other.value);
+
+      return left == right;
+    }
+    case ObjectType::NUMBER: {
+      double left  = std::get<double>(value);
+      double right = std::get<double>(other.value);
+
+      return left == right;
+    }
+  }
+}
+
 std::ostream &operator<<(std::ostream &os, const ObjectType &type) {
   switch (type) {
     case ObjectType::NIL:
@@ -64,3 +93,7 @@ std::ostream &operator<<(std::ostream &os, const Object &obj) {
 
   return os;
 }
+
+bool Object::operator!=(const Object &other) {
+  return !operator==(other);
+}

cclox_src/scanner/object.hh

@@ -30,6 +30,8 @@ struct Object {
       },
       value{std::move(value)} {};
   std::string to_string();
+  bool operator==(const Object &other);
+  bool operator!=(const Object &other);
 
   ObjectType type;
   std::variant<std::monostate, std::string, double, bool> value;