diff --git a/include/addon-tools.hpp b/include/addon-tools.hpp
index 988d85a..0c619eb 100644
--- a/include/addon-tools.hpp
+++ b/include/addon-tools.hpp
@@ -12,6 +12,7 @@
 #define JS_STR(...) Nan::New<String>(__VA_ARGS__).ToLocalChecked()
 #define JS_INT(val) Nan::New<v8::Integer>(val)
 #define JS_NUM(val) Nan::New<v8::Number>(val)
+#define JS_EXT(val) Nan::New<v8::External>(reinterpret_cast<void*>(val))
 #define JS_BOOL(val) (val) ? Nan::True() : Nan::False()
 
 
@@ -20,18 +21,18 @@
 
 #define REQ_ARGS(N)                                                     \
 	if (info.Length() < (N))                                            \
-		Nan::ThrowTypeError("Expected at least " #N " arguments");
+		return Nan::ThrowTypeError("Expected at least " #N " arguments");
 
 
 #define IS_ARG_EMPTY(I) (info[I]->IsNull() || info[I]->IsUndefined())
 
 #define CHECK_REQ_ARG(I, C, T)                                          \
 	if (info.Length() <= (I) || ! info[I]->C)                           \
-		Nan::ThrowTypeError("Argument " #I " must be " T);
+		return Nan::ThrowTypeError("Argument " #I " must be " T);
 
 #define CHECK_LET_ARG(I, C, T)                                          \
 	if ( ! (IS_ARG_EMPTY(I) || info[I]->C) )                            \
-		Nan::ThrowTypeError("Argument " #I " must be " T " or null");
+		return Nan::ThrowTypeError("Argument " #I " must be " T " or null");
 
 
 #define REQ_UTF8_ARG(I, VAR)                                            \
@@ -101,6 +102,10 @@
 	CHECK_REQ_ARG(I, IsExternal(), "void*");                            \
 	Local<External> VAR = Local<External>::Cast(info[I]);
 
+#define LET_EXT_ARG(I, VAR)                                             \
+	CHECK_LET_ARG(I, IsExternal(), "number");                           \
+	Local<External> VAR = IS_ARG_EMPTY(I) ? JS_EXT(NULL) : Local<External>::Cast(info[I]);
+
 
 #define REQ_FUN_ARG(I, VAR)                                             \
 	CHECK_REQ_ARG(I, IsFunction(), "function");                         \
@@ -115,11 +120,70 @@
 #define REQ_ARRV_ARG(I, VAR)                                            \
 	REQ_OBJ_ARG(I, _obj_##VAR);                                         \
 	if( ! _obj_##VAR->IsArrayBufferView() )                             \
-		Nan::ThrowTypeError("Argument " #I " must be an array buffer"); \
+		return Nan::ThrowTypeError("Argument " #I " must be an array buffer"); \
 	Local<ArrayBufferView> VAR = Local<ArrayBufferView>::Cast(_obj_##VAR);
 
 
 #define SET_PROP(OBJ, KEY, VAL) OBJ->Set(JS_STR(KEY), VAL);
 
 
+#define CTOR_CHECK(T)                                                   \
+	if ( ! info.IsConstructCall() )                                     \
+		return Nan::ThrowTypeError(T " must be called with the 'new' keyword.");
+
+#define ACCESSOR_RW(OBJ, NAME)                                          \
+	Nan::SetAccessor(OBJ, JS_STR(#NAME), NAME ## Getter, NAME ## Setter);
+
+#define ACCESSOR_R(OBJ, NAME)                                           \
+	Nan::SetAccessor(OBJ, JS_STR(#NAME), NAME ## Getter);
+
+#define SET_I(ARR, I, VAL) ARR->Set(I, VAL);
+
+
+#define SETTER_CHECK(C, T)                                              \
+	if ( ! value->C )                                                   \
+		return Nan::ThrowTypeError("Value must be " T);
+
+
+#define SETTER_UTF8_ARG                                                 \
+	SETTER_CHECK(IsString(), "string");                                 \
+	Nan::Utf8String v(value);
+
+#define SETTER_INT32_ARG                                                \
+	SETTER_CHECK(IsInt32(), "int32");                                   \
+	int v = value->Int32Value();
+
+#define SETTER_BOOL_ARG                                                 \
+	SETTER_CHECK(IsBoolean(), "bool");                                  \
+	bool v = value->BooleanValue(); // TODO APPLY bool TO REQ_BOOL_ARG
+
+#define SETTER_UINT32_ARG                                               \
+	SETTER_CHECK(IsUint32(), "uint32");                                 \
+	unsigned int v = value->Uint32Value();
+
+#define SETTER_OFFS_ARG                                                 \
+	SETTER_CHECK(IsNumber(), "number");                                 \
+	size_t v = static_cast<size_t>(value->IntegerValue());
+
+#define SETTER_DOUBLE_ARG                                               \
+	SETTER_CHECK(IsNumber(), "number");                                 \
+	double v = value->NumberValue();
+
+#define SETTER_FLOAT_ARG                                                \
+	SETTER_CHECK(IsNumber(), "number");                                 \
+	float v = static_cast<float>(value->NumberValue());
+
+#define SETTER_EXT_ARG                                                  \
+	SETTER_CHECK(IsExternal(), "void*");                                \
+	Local<External> v = Local<External>::Cast(value);
+
+#define SETTER_FUN_ARG                                                  \
+	SETTER_CHECK(IsFunction(), "function");                             \
+	Local<Function> v = Local<Function>::Cast(value);
+
+#define SETTER_OBJ_ARG                                                  \
+	SETTER_CHECK(IsObject(), "object");                                 \
+	Local<Object> v = Local<Object>::Cast(value);
+
+
 #endif // _ADDON_TOOLS_HPP_
diff --git a/package.json b/package.json
index 475eb76..8f02104 100644
--- a/package.json
+++ b/package.json
@@ -2,7 +2,7 @@
   "name": "node-addon-tools-raub",
   "author": "Luis Blanco <raubtierxxx@gmail.com>",
   "description": "A set of extra macros for node addons, shipped as C++ header file.",
-  "version": "0.0.4",
+  "version": "0.0.5",
   "main": "index.js",
   "keywords": [
     "node",