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- Subject: Re: Bitwsie operators in Lua
- From: David Jones <drj@...>
- Date: Mon, 19 Jun 2006 12:47:49 +0100
Lisa Parratt wrote:
David Jones wrote:
Treating an int as 32 bits indexed from 0-31 is just an optimised
representation of a table. Let's not elevate that optimisation to
the status of discrete mathematics. Personally I find that about
half the time when I want to use bitfields I end up overflowing the
32-bit ceiling anyway (in C this is), so you have to use non-basic
Please be explaining to me how you can do discrete mathematics in
stock Lua without such operators, without requiring one of those
academic theoretical computers with infinite CPU power and memory?
Either you're being a pedant for the sake of it, or so intensely
impractical I question why I bother.
I'm a practical pedant.
You know how to do set operations in Lua, just use tables. If I want
things to go fast, I'll use C. Why would I constrain myself to using
stock Lua? The whole point of Lua is that it's extensible, if I'm using
Lua I _expect_ to extend it, so why shouldn't I add a bit-table
library. If I want a more powerful language out of the box then I'll
Since I spent practically the whole of last year inside an 8-bit micro
with 3.25 KiB of RAM I find your comments about infinite CPU power and
memory amusing. We couldn't run Lua on it, but that didn't stop me
wanting to and fantasizing about it.
You ask too much. Can Lua be small, portable, fast, extensible, easy to
configure, and have benevolent and understanding caretakers? Yes. Can
it do all of these things and let you write: "(cast(OpCode,
((i)>>POS_OP) & MASK1(SIZE_OP,0)))"? Yes, of course. Without you
putting in a little extra work? No.
Personally I can live without the operator syntax for bitwise operators,
as I have to in C a lot of the time anyway, but it would be _nice_ to
have. Not wonderful, nor required, just nice. Is it worth hacking
around with the language just to add a nice feature? I don't know.
Why the stock Lua requirement?