Re: userdata environment

["Juris Kalnins" <juris@...>]

> Feel free to provide the benchmark results next time you talk about
> performance here, many people will simply ignore your comments
> otherwise (I assume you benchmarked that thing, otherwise you would
> have no way to predict it's "MUCH slower").

Fair. see below.

> A dozen lines for every small feature, and in the end you get a
> multi-gigabyte bloatware. I guess the authors have to plainly ignore
> some feature request to keep Lua small.

I wouldn't want such hacks to be included in core. One of the best things
about Lua core is that it is simple enough so that I can understand the  
code
and make required change myself. Most of the time. Putting all the
small hacks into core would make it indecipherable.
I was asking this question to make sure I've not overlooked something,
and to possibly hear if someone has done similar modification previously.
Sorry for witing in such a way that my intent was not clear.

==8<========================

require "socket"

local N = 1000000
local reg = {}
local obj = {}
setmetatable(reg, { __mode = "k" })

local setfe = debug.setfenv
local getfe = debug.getfenv

local t = 0
local function time()
    local t2 = socket.gettime()
    print(t2 - t)
    t = t2
end

for i = 1,N do obj[i] = newproxy() end
collectgarbage()
collectgarbage()

t = socket.gettime()

for i = 1,N do setfe(obj[i], obj) end
time()

for i = 1,N do reg[obj[i]] = obj end
time()

for i = 1,N do local x = getfe(obj[i]) end
time()

for i = 1,N do local x = reg[obj[i]] end
time()

==8<========================

0.13839292526245
0.3968460559845
0.10384202003479
0.1705310344696

same thing in C, using rawget/rawset:

timing 0.095036 sec
timing 0.559623 sec
timing 0.065464 sec
timing 0.205189 sec

... also note that pure lua_setfenv doesn't allocate resources and cannot  
throw, thus there is no need to put it in try/catch guards at C side.