RE: Request for clarification on reserved names

[Thijs Schreijer <thijs@...>]

> -----Original Message-----
> From: Thijs Schreijer
> Sent: maandag 21 april 2014 23:25
> To: Lua mailing list
> Subject: RE: Request for clarification on reserved names
> 
> > -----Original Message-----
> > From: lua-l-bounces@lists.lua.org [mailto:lua-l-bounces@lists.lua.org] On
> > Behalf Of Hisham
> > Sent: maandag 21 april 2014 19:17
> > To: Lua mailing list
> > Subject: Request for clarification on reserved names
> >
> > The Lua 5.2 (and 5.3) manual(s) say:
> >
> >    Lua is a case-sensitive language: and is a reserved
> >    word, but And and AND are two different, valid names.
> >    As a convention, names starting with an underscore
> >    followed by uppercase letters (such as _VERSION)
> >    are reserved for variables used by Lua.
> >
> > Does that mean (a) all names, (b) global variables only or (c) all
> > variables?
> >
> > The text says "names" which strictly speaking would mean option "a"
> > but I doubt this applies to table fields, so my original
> > interpretation was "b", but then I remembered that _ENV is special
> > even if it's a local variable (and yes, I've had to patch Lua 5.1 code
> > out there which used "_ENV" as a regular variable). I've also seen
> > tutorials out there that inadvertedly suggest _M (ugh) as a table name
> > for declaring modules.
> 
> 
> See this thread;
> http://article.gmane.org/gmane.comp.lang.lua.general/95848
> 
> Your comment on _ENV was not considered in the mentioned thread.
> 
> Thijs
> 
> >
> > This request comes in light of the recommendation in [2] to put
> > descriptive fields such as module._VERSION in module tables.
> > http://kiki.to/blog/2014/03/31/rule-2-return-a-local-table/
> >
> > I assume those are fine, but then it would be good to get the wording
> > clearer in the manual.
> >
> > Thanks!
> >
> > -- Hisham

I haven't looked up the use of _ENV (don't use it very much), but if _ENV is a special case, even when defined as a local or upvalue (according to Hisham), then the wording in the manual should be adjusted to clarify this. What does "names" exactly imply?
Roberto's answer related to globals only iirc.

Thijs