#Stair Engine First of all, we regard global code as a function and treat it accordingly. ##Object Struct Everything in Stair JS is Object and would be instantiated by a struct which is implemented by C.

struct Object{
	Type type;
	char* name;
	void* fileds;
	char* code;
	struct Object* this;
	struct Object* outFunction;
	char** arguments;
};

Fields of this structure would be filled according to its type. ##Dictionary

struct Dict;

This data structure would provide a flexiable method to record status of every object, whose key is name of field and value is object structure. Thus its structure is {char* : struct Object*} ##FuncProto We demonstrate basic plain code as FuncProto object which is used in instantiation of Function. And FuncProto would be instantiated by Interpreter automatically.

1. Flied type would be filled by FuncProto.
2. And interpreter would only fill code with text.
3. Besides fileds is set to be NULL.
4. Especially, outFunction must be set to the funtion where we define this function.
5. arguments must be specified explicitly. We pass a list of name to the FuncProto whenever instantiation of FuncProto happend.

##Function Whenever a function is invoked. A Funtion Object would be instantiated by corresponding FuncProto.

1. type would be set to Function
2. And fileds would be allocated new memory space, which represented by a pointer to Dict.
3. Copy FuncProto's code to Function's code filed.
4. Pass arguments to this structure as well as outFunction.
5. This also need to be specified, but it depends on specfic condition. ###Function Invocation In Function invocations, there are following two situation. f(); this we pass is current local this. a.f(); And in this situation, this is pointer fo Object a.

##Object A Object could be instantiated by Function. Basic operation is like the way we perform in Function instatiation but this must be a new pointer to struct Object that we allocate recently.

##Primtive Type We present Primtive Type in format of Struct Object. However, Javascript treat her reference mechanism like Java. Its fileds would be corresponding type. Primtive Type is passed by value. Thus, we must create a new object as same as original one. Currently, following Primtive Type is planed to be implemented.

1. int
2. float
3. string
4. bool

##Parameter Pass Parameters would be passed to the fields. And interpretor would scrutinize the number of parameter is matched or not. ##Return Value Simply, we just return struct Object. ##Function Closure In order to accomplish Function Closure, we introduce outFunction. Interpretor would scan local scope to find current variables. It would find variables in outFunction if not find in local scope yet. Searching priority is presented below.

1. Local scope
2. This
3. outFunction Recursively.

##Code Slice We confine syntas of Stair JS restrictly. Every operand and operator must be sperated by blank. Similarily semicolon would split every statement.

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