Re: require, module, globals and "magic"

[Lorenzo Donati <lorenzodonatibz@...>]

Hi all!
Sorry for cross-posting from scite-interest, but since I "let myself 
go"  in a recent post there (replying to Steve Donovan, before I saw 
this thread) about this same topic, I will copy and paste my two 
eurocent from there (and add a bit more) :-) .

<cross-post>
I'm not an extremist about globals (regardless of language), but I still 
try to avoid them like plague, except for quick and dirty throw-away 
scripts/programs.
In the years I've grown a sort of itch about them: whenever the code I'm 
writing grows longer than, say, about 20-30 lines, I feel an urge to 
make any symbol "as local as possible" :-) .
For the same reason I feel rather disturbed when external code has 
"unexpected" side effects (well, with Lua modules this is not so 
"unexpected"... :-) ). I highly value the principle of least surprise 
and unknown globals popping up from almost nowhere is not something I 
would want to care about!
I'm not really an expert of Lua, but I don't see the _need_ for a module 
to make its "symbols" directly accessible as globals (or as a global 
table). It's Just a convenience, but if the module returned the "symbol" 
table (as you point out [Steve D.]), there would be no need to put 
anything in _G (or am I missing something?!?). This is maybe more 
troublesome with modules loaded indirectly: in this case I may not even 
know that something is being put in _G (the module I require might 
behave "nicely", but require in turn another module that doesn't)!
</cross-post>

Therefore I welcome the upcoming change in 5.2 (_ENV, module 
deprecation, etc.), but I admit that devising a clear protocol for 
modules definition (as many have pointed out recently on this list) is 
something that IMHO should be done. I know (and like) Lua's policy of 
providing mechanisms instead of mandating practices, but at least a 
common "endorsed" convention on module definitions could help code reuse 
and maybe Lua diffusion. In this respect, whereas I appreciate Lua 
minimalism, I think that an endorsed standard for modules could make 
more libraries "play nice" to each other and so help establish a 
community-driven "standard libraries collection" (IIRC there was a 
thread about this some months ago).


Best Regards,
Lorenzo