Re: More on environments and objects

[Rici Lake <lua@...>]

On 27-Aug-05, at 10:23 AM, Aaron Brown wrote:

> Rici wrote:
>
> > I'd put bit operations in string.*, not math.*.  We can
> > argue about this after 5.1 comes out.
>
> Forgive me for jumping the gun, but I'd be interested in
> seeing what kind of interface you're thinking of.  Do you
> imagine them taking or returning strings?  What kinds?
> (Maybe something like string.char(1, 1) represents
> 0000 0001 0000 0001 i.e., 257?)

Both taking and returning strings.

Numbers have a fixed but unspecified length, so you cannot reliably 
test bit `i' in a number; you have no way of knowing whether `i' is in 
range or not.

I use bit operations for fairly long bit strings. Using bits in a 
number in order to compress a small number of "flags" into a single 
operation strikes me as an abuse both of flags and numbers, but that 
might be just me being a purist.

Strings are immutable, so you cannot "set" a bit; you need to create a 
new bit string with a "bitor" operation. In practice, that is often 
convenient because the resulting bit strings are interned and can be 
used as table keys (in some applications, that's exactly what you want; 
in others, it's a little bit of regrettable overhead).