Re: Lua-l: Support for lua_next on C userdata objects

[Javier Guerra <javier@...>]

On Wed, May 20, 2009 at 4:28 PM, drake <support01@mountainstorm.co.uk> wrote:
> How do I implement something with the lua C api to handle calls on it by
> lua_next?

the easiest way is to replace the next() function with your own, that
honours some '__next' field on your metatable, and call the original
next() if there's none.

something like this (untested):

local oldnext=next
function next(t)
    local mt = getmetatable(t)
    nx = mt and mt.__next or oldnext
    return nx(t)
end

> One other point.  As I'm passing references to Lua objects off into the
> world of C++ (kroll), how do I (in C) increment/decrement the Lua reference
> count so that the Lua gc doesn't try to discard it and cause my code to go
> pop?

store them in the registry


-- 
Javier