Re: Praise of Lua from a game developer

[steve donovan <steve.j.donovan@...>]

On Thu, Jul 26, 2012 at 10:21 PM, Pierre-Yves Gérardy <pygy79@gmail.com> wrote:
> Does that approach handle mutable upvalues?

Yes, but slowly, since some metamethod/debug magic is needed to set
them.  For immutables, it's much easier.

local boo = 1
local M = {}
...
function M.foo() return boo end
..

OK, so to recompile M.foo we wrap it so:

local _v = ...; local boo, M = _v.boo,_v.M
function M.foo() return boo end

and pass this chunk a table extracted from the values of its current upvalues.

It can't of course acquire new upvalues without a complete
recompilation of the module. That's fast enough, true, but the issue
here is preserving module state as long as possible.

steve d.