Re: another hat in the ring regarding Lua 5.2: static typing

["Alex Davies" <alex.mania@...>]

Impressive that jit 2.x performs loop hoisting, but how is it that neither 
assert nor type need to be checked? The only thing I can think of is that it 
is assumed that they are both stored in upvalues, and that jit 2.x checks 
that nothing modifies those upvalues. If so, wouldn't that cause problems 
with debug.setupvalue =/? Intrigued. Sounds good though.

- Alex

----- Original Message ----- 
From: "Mike Pall"


> The first line is transformed into a single ISNUM ucode. This is
> a type-checking guard which exits the trace if its precondition
> later turns out not to be true.
>
> The bytecode generated for the first line is not trivial (it has
> two calls and a conditional expression). The transformation to a
> single ucode is quite involved, but most of it can be done while
> recording: