Re: checking for Not a Number?

[Rici Lake <lua@...>]

On 29-Dec-06, at 6:10 PM, Joe Smith wrote:

> I'm still not sure that this code is correct:
> > else if (ttisnumber(key) && nvalue(key) != nvalue(key))
> >      luaG_runerror(L, "table index is NaN");
>
> If nvalue(key) was stored in a varible, which was compaired to itself, 
> then I would agree that it
> would be required to do the right thing.

nvalue(key) is actually a macro which access the numeric value from a 
union in the struct which key points to. So it's completely safe.

Even if the value were widened in one of the expansions and not in the 
other, the comparison would still work as expected since widening 
cannot alter the value.