From: Marty Kent
Subject: Anyone using pcl (clos) under Allegro Common Lisp?
Date:
Message-ID: <24158@ucbvax.BERKELEY.EDU>
Is anyone out there doing anything with pcl (CLOS) under Allegro common lisp?
I've recently gotten the sources from parcvax, and I'm interested in the
possibility of rewriting a bunch of code I've done in Object Lisp, in pcl.
(Got that?)
One reason I'd like to do this is that I'd expect to get a substantial speed
increase. The Allegro documentation says that Object Lisp is not to be
expected to run at high speed, but what about the implementation of pcl? Since
it's still in some kind of early state of development, what kind of
performance can one expect from the current version? I'd be very interested
to hear from anyone who's actually done any measured comparisons between the
two systems.
Another factor possibly in pcl's favor is that it's supposedly on the way to
becoming a standard, while Object Lisp's future seems to be less than rosy...
Do you feel pcl is in fact emerging as a standard like common lisp (I mean
widely accepted like common lisp, not necessarily funky like common lisp :-)
or are there other lisp object extension systems clearly "in the running?"
I'd be interested in hearing from anyone with thoughtful stuff to say about
these things.
Marty Kent Sixth Sense Research and Development
415/642 0288 415/548 9129
·····@dewey.soe.berkeley.edu
{uwvax, decvax, inhp4}!ucbvax!mkent%dewey.soe.berkeley.edu
Kent's heuristic: Look for it first where you'd most like to find it.
From: Chris McConnell
Subject: Re: Anyone using pcl (clos) under Allegro Common Lisp?
Date:
Message-ID: <3978@zodiac.UUCP>
The current version of PCL is implementing most of the Common Lisp
Object System (CLOS). This will be the Object Oriented Programming
standard for Common Lisp. I believe it will be officially approved
sometime in June.
PCL is fairly portable. I plan to bring it up in Allegro in the next
month. If you accept the most generic implementation, it should
already run in Allegro. (In fact, it may even have optimizations
already since Allegro is really Franz and it already runs in Franz.)
There are numerous ways to get it to run faster on a given
implementation, but modifying the PCL code requires a very good
knowledge of Lisp. I have done a lot of it fixing bugs and adding
features, and I can tell you that it is no picnic.
I ran some benchmarks a while ago on a Symbolics and a Sun running
Lucid. The speed was better than I thought it would be for an early
and portable implementation. Creation is slow, but execution speed of
generic functions is very good. (Some of this is due to the caching
mechanism that makes more recent methods faster.) We developed an
image understanding environment using it, so the speed can't be too
slow!
I have been working in CLOS for a year (> 25,000 lines), and I have to
say that even in its presently incomplete state that I love it. I
have worked extensively in Flavors, an in house system called SOPE and
some in Smalltalk. CLOS is far and away my favorite. Multiple
specializers are great, especially on normal Lisp objects. The spec
takes great pains to make all of the hooks that are needed available
and public while still allowing implementations to do all of the
things that are required to make things run fast.
From: Gail Zacharias
Subject: Re: Anyone using pcl (clos) under Allegro Common Lisp?
Date:
Message-ID: <306@spt.entity.com>
In article <····@zodiac.UUCP> ········@ads.com (Chris McConnell) writes:
>PCL is fairly portable. I plan to bring it up in Allegro in the next
>month. If you accept the most generic implementation, it should
>already run in Allegro. (In fact, it may even have optimizations
>already since Allegro is really Franz and it already runs in Franz.)
First, let me clear up something here. I believe the original question was
about Allegro CL for the Mac (which is really Coral Common Lisp) not about
Allegro CL for Unix (which is really Franz Extended Common Lisp). Franz
conditionalizations would certainly not work in Coral or vice versa. The two
implementations have nothing in common aside from the name they're being
marketed under, and some marketing person deserves an eternity in hell for
causing this confusion.
Secondly, PCL has already been brought up under Coral Common Lisp, with all
the usual optimizations that PCL allows for. See the "coral-low" file that
comes with PCL.
Finally, regarding the original question - Object Lisp in CCL is not very
efficient as native object systems go, but it IS a native implementation and
is faster than PCL. So you won't speed up your code in the short term by
going to PCL. However, in the longer term, Coral will provide a native
implementation of CLOS, which should be more efficient than Object Lisp (and
in any case, Object Lisp will get even less efficient since we'll probably
re-implement it as a compatibility package on top of CLOS). So whether you
decide to switch now depends on the relative importance of short-term vs
long-term to you... One possibility is to stay with Object Lisp but
adapt a coding style which doesn't take advantage of its special features,
so as to make future conversion easier (e.g. maintain a strict distinction
between classes and instances, don't create new instance variables on the fly,
etc.).
--
··@entity.com ...!mit-eddie!gz
Now let's all repeat the non-conformist oath.
From: Jeffrey A. Sullivan
Subject: Re: Anyone using pcl (clos) under Allegro Common Lisp?
Date:
Message-ID: <1205@cadre.dsl.PITTSBURGH.EDU>
In article <·····@ucbvax.BERKELEY.EDU>, ·····@dewey.soe.berkeley.edu (Marty Kent) writes:
> Another factor possibly in pcl's favor is that it's supposedly on the way to
> becoming a standard, while Object Lisp's future seems to be less than rosy...
> Do you feel pcl is in fact emerging as a standard like common lisp (I mean
> widely accepted like common lisp, not necessarily funky like common lisp :-)
> or are there other lisp object extension systems clearly "in the running?"
>
Well, PCL is migrating toward a full implementaiton of CLOS (the Common Lisp
Object System), but it aint QUITE there yet. It is, however, quite usable.
And very powerful. I know that there have been some optimizations in it (I
read the code), but there are no broad-based ones, and I can not vouch for its
speed. I am using PCL entirely in a project of mine, and haven't had
any complaints, but I am not concerned with efficiency at this time.
CLOS _is_ the standard OOPS for CL, so using it is no bad idea. There
is no doubt that CLOS (of which PCL is slowly implemeting) is the only
OOPS officially supported by CL, so don't worry.
There is, however, a LOT of code to CLOS/PCL, and it takes quite a tot
of memory, while OL doesn't. Note that OL's future is not so bad,
Coral will almost definitely implement a copy of OL in CLOS (it's not
too hard...) just for compatibility's sake.
--
..........................................................................
Jeffrey Sullivan | University of Pittsburgh
···@cadre.dsl.pittsburgh.edu | Intelligent Systems Studies Program
······@PittVMS.BITNET, ······@cisunx.UUCP | Graduate Student
From: Barry Shein
Subject: Re: Anyone using pcl (clos) under Allegro Common Lisp?
Date:
Message-ID: <22993@bu-cs.BU.EDU>
I've been using PCL (and CLX) a lot lately under KCL on my Encores and
Suns here. I like PCL, it seems to be a very clean design for an
object-oriented set of tools for common lisp, fits into the language
design well.
The only thing I miss is a user's manual tho I assume that one is in
progress, the supplied documentation tends to read more like an
academic paper justifying its features (the supplied reference manual
is ok, but it often just refers back to the first part. Anyhow, the
hard part of mastering something like PCL is not understanding what
the pieces do (at least not for me) but understanding how they are
expected to be used together (nothing deep here, some clever,
extensive, annotated examples might fill the gap.)
At any rate, well done!
-Barry Shein, Boston University