Re: The purpose of LUA_ENVIRONINDEX pseudo index

[Jose Luis Hidalgo Valiño <joseluis.hidalgo@...>]

El 29/08/2006, a las 2:58, Mildred escribió:

> > For example,
> > could lua_environindex be used to hold data locally( or private ) to
> > a C function that can be accessed in successive calls?
>
> I don't know about LUA_ENVIRONINDEX but if you want to keep some
> variables between the function call (like static variables in C) you
> may find closures useful.

I'm not sure if closures are mutable or not (but it's name suggest  
they are not mutable), if you want a mutable variable, that can be  
accessed by a function, you should use one of these pseudo indices:
    - LUA_REGISTRY --> accessible by C code only
    - LUA_GLOBALSINDEX ---> the thread environment, for global  
variables.
    - LUA_ENVIRONINDEX --> that's new to lua 5.1 and I'm not sure  
how to use it.

LUA_ENVIRONINDEX seems a way to hold data locally to a set of  
functions ( or only one ) but without loosing the possibility of  
access the full global environment (the thread environment) through  
LUA_GLOBALSINDEX.

In lua 5.1 lua_setfenv "changes" the behavior of LUA_ENVIRONINDEX or  
LUA_GLOBALSINDEX ? I'm not sure.

Jose L. (PpluX)