Re: [ANN] LuaJIT-2.0.0-beta1

[Mike Pall <mikelu-0911@...>]

Timm S. Mueller wrote:
>    fmt = luaL_checkinteger(L, -1);

Aiiieeee ... you're using negative stack indexes with the
luaL_check*() functions?

Maybe the Lua manual could be a bit more clear about this point,
but it *does* say this at the start of section 4:

  "Because the error message is formatted for arguments (e.g., "bad
  argument #1"), you should not use these functions for other stack
  values."

For me this implies, that only positive values cause defined
behaviour.

Obviously the standard Lua implementation is somewhat more
lenient: it properly checks the type of the stack object at the
relative position, but it would report a pretty meaningless error
if the check ever failed (like "bad argument #-7").

Currently LJ2 happily misinterprets negative indexes for these
functions. Sooo ... what to do? I guess I'll have to bite the
bullet and support some undefined behavior, too. :-/

Patch will follow shortly.

--Mike