Re: Why Lisp supposedly "sucks for game development"

From: Duane Rettig (duane_at_franz.com)
Date: 10/22/04 

Date: 21 Oct 2004 17:44:33 -0700

Kenny Tilton <ktilton@nyc.rr.com> writes:

> Duane Rettig wrote:
> > Cesar Rabak <crabak@acm.org> writes:
> >
>
> >>Kenny Tilton escreveu:
> >>[snipped]
> >>
> >> >
> >> > Given that C/C++ is only 20% faster than Lisp, and that so much in 3D
> >> > gaming is handled by the GPU, and that, where the application does
> >> > get involved, 3D performance is achieved by algorithmic tricks such
> >> > as smart culling, which any language can express... I suspect C/C++
> >> > as superior for gaming is nowadays just holdover conventional
> >> > mis-wisdom.
> >> >
> >>I think the only way we can bring this 20% as a tradeoff is to explain
> >>some managers that the project cycle can be reduced in 50% by using a
> >>more expressive language.
> > Why do you assume that the 20% has to stay? Is it a fundamental
>
> > language issue that makes C/C++ 20% faster than Lisp? Is that statement
> > really true, or are we just spouting truisms that we've heard?
> > I didn't correct Kenny on his statement, ...
>
>
> Feel free. <g>

OK. You asked for it :-)

> I just wanted to posit a worst-case difference and make
> the argument that it would be irrelevant even if true.

But it's not irrelevant. Oh, it may be irrelevant to you,
but when you argue with a person who claims it is relevant,
then it becomes hard to keep from talking at cross-purposes,
and even harder to convincce the other person, if he is wrong,
that it is indeed irrelevant. Catch-22.

> Except that Cesar then trumped me with the "dopey manager" card.

A powerful and deadly card, one not feared enough by us in the
Lisp community. You played a weak hand, when you should have
led with your ace.

> Which is why i
> keep saying, do not even worry about dopey managers or butthead
> coworkers or numbskull students... the great thing about them is that
> they will be screaming for Lisp training about two seconds after it
> becomes The Latest Thing, and that will not be long by the look of
> things. Way too many people are looking into Lisp and looking away
> from static languages. Practical Common Lisp's release in 2004 (uh-oh
> <g>) will really shake things up.

I will never agree to the statement that "too many" are looking
into Lisp. I know that some people really do feel that way, (i.e.
if the unwashed masses start flocking to Lisp it will somehow
become diluted) but I don't believe it for a second. Lisp's
strengths are its own, and its weaknesses are its strengths, and
no deluge will change that; we will never have "too many" Lispers.
The fact that we still have detractors still keeps us on our toes...

> Maybe I should turn Cello into a games engine. I see from one of the
> Roads that one of the game forums is a hotbed of Lisp advocacy. Hmmm...

Hmm, indeed. And?... Do we have enough gamers in the ranks?

So, now, about this 20% business; where do _you_ come up with this
number? Yes, this is a challenge; please back up your claim with
references

The bottom line is that all languages eventually get down to the
hardware, and it comes down to the same transistors turning on
and off - they switch just as fast for one language as for another;
it is just a question of how many times, which is an indicator of
how low-level your language can go. But in this bit-Lambada [sic],
people tend to confuse the ordering of things, because Lisp is usually
though of as a high-level language, and proponents of Lisp don't
like to thing in low-level terms. In fact, C is a very low-level
language, but it is surprisingly far away from the lowest level -
the machine level (note that I didn't say the assembler level; that
tends to _almost_ match the hardware, but there are sometimes assemblers
that actually can't support their own hardware, at least transiently).
Becase Lisp is a language generating language, though, it can breeze
through the entire realm; it can (and does) generate to the very bit
level that is executed. So, being both a high-level and a low-level
language, we need to honor those features of the language that allow
such to-the-metal grinding even though our own tendency is to run
away from that metal as fast as possible and layer ourselves with
higher-level concepts.

Feel free to identify or not with any portions of that last paragraph.
It is a general statement, and is not pointed at you but at our
community as a whole.

Off my soapbox, now... 

-- 
Duane Rettig    duane@franz.com    Franz Inc.  http://www.franz.com/
555 12th St., Suite 1450               http://www.555citycenter.com/
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