Re: Philosophy ;-)

[Luiz Henrique de Figueiredo <lhf@...>]

>1. Does your licence allows to use part of your code?

I think so, but I'm not sure myself.
I'll have to talk with the rest of the team and perhaps add a sentence to
the copyright notice.

>I briefly though about
>using your expression parser in another project, but I doubt it can be done
>easily, as it must be deeply dependent of the whole project (ie. difficult
>to isolate).

One *easy* way to reuse the expression parser is to use it in Lua,
as explained in the paper and in the seminar slides.
But if you want it in C, you'd probably find it easier to write your own,
perhaps in yacc. Early versions of Lua include a yacc grammar for Lua.
There's also "hoc", a simple language describe in "The UNIX Programming
Environment" and probably available in the internet (perhaps at the authors
sites). And many others very small languages (eg. etalk and bob).

>But does it work the other way around? I mean, if I write another Lua
>interpreter (again, I don't have the skill to do it, and even less the
>time!), which mimic exactly the Lua syntax and behavior, can I call it a Lua
>interpreter?

Yes, definitely! I'd love to see this as I think this would take Lua to
a different level as an influential language. Do Perl or Python or TCL have
more than one implementation? But Scheme does.

>A word about the (moderated) criticisms I saw here. I think the authors are
>injustely accused of not being reactive about change suggestions. I believe
>they don't work on Lua on full time, probably working on other projects. So
>they may have not so much time.

That's right, but Lua is a major concern for us and is probably Roberto's main
project (as he says in his web site). Roberto is definitely the leader of the
team -- he alone makes changes to the code and thinks about most changes to
Lua. I take care of luac, the web site, the mailing list, etc.  Waldemar takes
cares of tools and the use of Lua in TeCGraf. But we three have academic
careers that need close attention. (Roberto is the language expert; Waldemar
and I are mostly graphics people.) Despite other projects and papers to write,
we have frequent (and heated) discussions about the future of Lua, many times
motivated by postings to this list.

So, yes, we do hear what everyone says here, but not everything can be added
to Lua, some for technical reasons, some simply because of taste.
Plus lua-l has reached a size where other people can answer questions.
There are many knowledegable people here, and not only about Lua!

>And time spent on heated discussions on this
>mailing list is time not spent on Lua code...

Oh, yeah! With 120 messages just this month (that's one every 2 hours!),
it's hard to read them all closely, let alone answer them. (we had network
problems in the past couple of days and it was a slight relief that lua-l was
slient for a while... :-)

But again, we do take notice of what goes on here.
We just have to keep focused on what we want to do with Lua.
One thing is certain: we want it small and as simple as possible,
but not simpler (Einstein? :-).

That was a long message. Let's go back to Lua now :-).
--lhf