Re: Is the registry needed?

["Soni L." <fakedme@...>]

On 30/09/15 03:08 AM, Dirk Laurie wrote:
> 2015-09-30 2:44 GMT+02:00 Soni L. <fakedme@gmail.com>:
>
> > The registry, a table, is SLOW. Can we use upvalues instead?
> No. The two things are totally different.
>
> The registry, by definition, is a "predefined table that can be used
> by any C code to store whatever Lua values it needs to store."
>
> Upvalues, by definition, are "the external local variables that the
> function uses, and that are consequently included in its closure".
>
> In C, the distinction is even sharper. The moment you create a new
> lua_State, you have a registry, but you don't have any upvalues.
> You need a `funcindex` when calling `lua_getupvalue`.
>
> If your question is actually short for "Are there some things that
> careless programmers stuff into the registry that would better be
> done using upvalues?" then the answer would be "Yes, of course".
In Lua you have 2 options:

1) Use function upvalues. (for local access)

2) Use the module table. (for shared access)

There's no such thing as a "registry" in Lua, it only exists in C (and 
debug). I want to bring Lua on par with the C API and vice-versa.

I still don't see how the registry is needed, when the Lua side doesn't 
need one.

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