Re: Creating a Lua roadmap

[Andy Wingo <wingo@pobox.com>]

On Tue 19 Apr 2011 23:11, Phil <theseaisinhere@gmail.com> writes:

> I have recently checked out the Lua branch. I want to make it seaworthy.

Cool!  It does indeed need some more loving :-)

> I've requested to be added back onto the Savannah group, can someone
> do that? TIA.

Sure; saw your mail before reading this, so please disregard that
confirmation message.

> git co -b lua origin/lua
> git co -b stable-2.0 origin/stable-2.0
> git branch lua
> git rebase stable-2.0
>
> Is that right?

Yes, except perhaps "git checkout lua" instead of "git branch lua", no?

> TODO:
>
> - Missing standard library functions: math.modf, table.sort, module

I think Mark's recent division work should help with modf.  I don't
recall what's needed for the rest.

> - Missing getfenv/setfenv. You can tell Lua to look up global
> variables in different environments.
>   Frankly this is going to be really annoying to implement and I'd
> rather leave it off until someone complains about it being missing, if
> that's cool.

OK.

> - Variable arguments, multiple returns.

This is the big one.

> FIXME:
>
> - Use prompt and abort instead of throw and catch.

Yes this will be good too.

> - And/or expressions evaluate expressions multiple times.

Whoops!

> - The keyword "break" does not work correctly.

Yes; to fix.

> Andy, I think you wrote "FIXME: use module binders instead" in
> compile-tree-il.scm, what does that mean?

For global refs, the current code does a lookup every time a function is
called, where instead it should allow the variable to be cached the
first time it is looked up.  The way to hook into the process of caching
a variable for lookup is module binders.  They aren't documented
though.  Search for "binder" in ice-9/boot-9.scm and in modules.c.

Cheers,

Andy
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