[Date Prev][Date Next][Thread Prev][Thread Next]
- Subject: Re: Questions about writing a C library
- From: Brian Hook <hook_l@...>
- Date: Tue, 23 Mar 2004 16:05:12 -0500
On Tue, 23 Mar 2004 20:37:25 +0000 (UTC), Phil Bewig wrote:
> Perhaps you are suggesting that I should implement linked lists in
> lua natively rather than in c, and indeed I have seen libraries for
> that, but that seems expensive to me compared to the c
If you're worried about the cost of doing something like:
t = foo.next
Then using ANY scripting language isn't going to be an option. It's
generally well accepted that a non-native-compiled language is going
to be at least an order of magnitude slower than going native.
> pointer reference. In lua, getting the next item in a list means
> computing a hash using arithmetic, indexing into the array that
> holds the hash table, then chasing pointers down a linked list,
> comparing keys until you find the one you want.
Off the top of my head:
function apply( l, f )
while l ~= nil do
l = l.next
That's similar to the C code you'd expect, and with a bit more power
because of closures.
That said, I'm not sure if your linked list library was really
intended to be "useful" as much as it was intended as a learning
vehicle. I can't imagine anyone using a linked list library in C
though -- it's basically trying to usurp a lot of the core Lua
internals for no appreciable gain.