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On 13/01/17 08:27 AM, Dibyendu Majumdar wrote:
On 13 January 2017 at 09:52, Daurnimator <> wrote:
On 13 January 2017 at 20:01, steve donovan <> wrote:
On Fri, Jan 13, 2017 at 9:43 AM, Dirk Laurie <> wrote:
Isn't it possible to mimic setfenv and getfenv (inefficiently) in
"pure" Lua 5.3 via the debug library?
Well, naturally but the documentation also warns that the debug
library can be very slow.

_ENV never freaked me out because I never use it ;)  And never missed
setfenv either.
_ENV can be a bit weird to get used to, but once you start using it
you start to come up with nice new patterns/idioms.

However the reason I don't use _ENV more often is I often have to end
up writing code with lua 5.1 compatibility.

In Ravi I would like to add support for 5.1 and 5.2 backward
compatibility. Has anyone implemented the missing features of 5.1 in
5.3 that I can look at?

I have no experience with 5.1 and do not know how setfenv/getfenv ad
related C api functions should be implemented, but I would like to add
these to Ravi.

Thanks and Regards

I did some thinking on it a while back, but I can't recall what I came up with...

I *think* I talked about it somewhere on my github[1], maybe on the SExLua repo[2], but yeah idk.

(Or maybe it was on this list, scattered across multiple threads...)

Just make every function have an _ENV, whether it uses globals or not. Then basically upvaluejoin when setfenv and return it when getfenv - don't bother with temporary in-function environments, since those are not *the* function's environment.


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