16 Feb
2018
16 Feb
'18
8:51 a.m.
On Thu, Feb 15, 2018 at 9:41 PM, Larry McVoy <lm(a)mcvoy.com> wrote:
On Thu, Feb 15, 2018 at 09:38:02PM -0500, Dan Cross
wrote:
Common
That's a tad unfair.
It *can* be fast, it's just that the "Lisp" you're writing in that
case
probably isn't the Lisp you wanted to be writing when you read about how
cool and elegant Lisp was: you're avoiding some constructs to prevent
boxing and unboxing arguments (e.g., put things inside of labels or flet's
instead of defun's or passing arbitrary lambdas around) or generating
useless garbage (don't cons up a list; setq the cdr) and favoring others
that are less elegant to get better object code out of the compiler.
If you can stomach the death-defying twists and turns from all the hoops
you have to jump through for all of that nonsense, then you can make it
fast -- but at the loss of the expressive advantage. But that trade-off
begs the question: why not write in a language that lets you write fast
(executing) code without jumping through hoops? That's a fair thing to ask
and most of the answers in Lisp's favor aren't particularly great.
- Dan C.
On Thu, Feb 15, 2018 at 8:56 PM, Lawrence Stewart
<stewart(a)serissa.com>
wrote:
> ITA???s airline flight booking system, that was used by Orbitz and
others
> was pretty much entirely written in Common
LISP, and it was certainly
both
> large and commercially successful. Orbitz
was bought by Google for
$700
> million. I don???t know how much of the
LISP survived sustained
attention by
Google.
Google bought ITA, not Orbitz. Most of the logic in QPX is still in Lisp, but it's not what you'd call
"idiomatic" CL code. If one reads a
bunch of Paul Graham and Peter Norvig books and then gets onto QPX with
the
expectation of that sort of elegance, you end up
pretty unhappy pretty
quick. They do a lot of things very differently to squeeze as much
performance as they can out of what has, historically speaking, been a
fairly mediocre compiler.
Which is sort of my point. I don't know all the details but lisp and
performance is not a thing.