Lua 中 OOP 库的设计问题

Question

I implemented a small OOP library in Lua, and two things are not quite right yet. I need your advice!

How to call super()?

I need to make a choice. The three arguments I need to resolve a call to super() are:

• The class from where the call is being made (CallerClass)
• The instance to be passed (self)
• The name of the method (method)

I hesitate between these three forms:

--# Current way:
self:super(CallerClass):method()

--# Variant, which I now find cleaner:
CallerClass:super(self):method()

--# Python style, which is nice too:
super(CallerClass, self):method()

Which one looks nicer and or easier to remember to you?

Do I need a Class symbol?

In the current version, the only concept is a table named Object , which you can subclass. I have another version where I introduced a Class symbol.

Its use is to tell instances from classes. Ie :

assert(Object:isKindOf(Class))
local object = Object:new()
assert(not object:isKindOf(Class))

I find it very handy to document and enforce that a method must be called from a class, by starting the method with:

assert(self:isKindOf(Class))

Is it usefull in Lua? What do you think? Thanks!

Answer 1

--# Python style, which is nice too:
super(CallerClass, self):method()

Answer 2

我会说有一个类对象 - 更多的信息/元数据更好

Answer 3

Thanks Chris, done.

For those interested, the code is published on the Lua Users Wiki, see ObjectLua .