Re: Lua and composition

[云风 Cloud Wu <cloudwu@...>]

http://lua-users.org/lists/lua-l/2016-04/msg00183.html  :)

Soni L. <fakedme@gmail.com>于2017年3月1日周三 上午9:11写道：

So, Lua has very limited OOP:

object:method() --> object.method(object)

But, there are other forms of OOP which are useful:

object.system.method(object)
object.trait.method(object)

These could be added to Lua as a new syntax sugar, the `:.` syntax:

object:system.method()
object:trait.method()

I believe Lua would benefit from this. Sure, you can just keep a
reference to the object in object.system/object.trait, but then you
can't dynamically add new arbitrary systems/traits:

object.trait = sometraitimpl
object.trait:method() -- wait, why are you not modifying my `object`?

object.system = somesystem
object.system:method() -- ??? you're supposed to modify `object` D:

object.system.ref = anotherobject -- brokenpatching at its finest

And this is why I think it's a good idea.

This could also support any level of nesting:

a.b.c:d.e.f.g() --> do local c = a.b.c; c.d.e.f.g(c) end -- note how
`a.b.c` is only evaluated once

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