Re: __index returns truncated to one, why?

[Peng Zhicheng <pengzhicheng1986@...>]

On 04/12/2014 05:07 PM, duz wrote:
> On 12.04.2014 10:10, Dirk Laurie wrote:
> > 2014-04-12 5:02 GMT+02:00 Peng Zhicheng <pengzhicheng1986@gmail.com>:
> >
> > > the `metamethod' mechanism in Lua is FALLBACK, not OVERRIDE.
> > > the __index metamethod is fallback for non-existance keys.
>
> This does not apply to userdata, which is what I use.
> I use metatables mostly like this:
>
>  Step 1: Do some useful stuff in c/c++.
>  Step 2: Represent it in Lua via Userdata+Metamethods.
>  Step 3: Use it in fairly small scripts.
>          If matters get too complex, go back to 1.
>
> I always need __index.
> Artificially limiting its capabilities is wrong. For me.

I do bindings too.

in case my binded userdata is some kind of container type, like vector, hashtable,
associative array, or even list when needed, then the current semantic of
__index metamethod is _right_ for me.

if the userdata is not container like but object like, I would merely use the __index
metamethod to retrieve data fields and class methods for that object. and it
is still _right_.

I don't see any limitations here,

maybe you have other use cases which I didn't see.

> >
>
> This sounds like you've been carried away and hit your head
> trying all sorts of strange things that would never occur to me.