Subject: Re: Reviews for lisp implementations
From: Erik Naggum <>
Date: 1999/04/15
Newsgroups: comp.lang.lisp
Message-ID: <>

* Arthur Lemmens <>
| I've waited two days for people with more experience to shed some
| light here.  But, apparently, nobody is willing to burn his fingers 
| on a comparison between Harlequin and Franz.

  that's because this is the kind of stuff lawsuits are made of.  you need
  a protective wrapper of serious legal quality to dive into this matter of
  comparing products in general.  not that I think Franz or Harlequin will
  sue anyone, but most professionals are aware of the problems of comparing
  products, and consequently avoid it, at least in public.

| So here's my (very personal and very subjective) impression, based on
| about 1000 hours of working with Harlequin's Lispworks, 50 hours of
| experiments with Franz' previous version (don't remember version number)
| for Windows and about 5 hours of playing with Franz' current version.
| All of this on Windows 95/98.

  although extremely important to inform your readers of (thanks), this
  makes your comparison "weak".  (I wouldn't be able to provide a stronger
  comparison, by the way.)

| * Price 

  price comparisons are more dangerous than any other comparisons.

| * Conformance to standards.

  this comparison should be performed by someone very familiar with the
  standard and its semantics, because impressions of non-conformance may
  actually be within the bounds of conformance, and some non-conformances
  may be insignificant and easily fixed if the vendor is alerted to them.

| My impression is that both companies are pretty good at conforming to the
| ANSI spec, but that Harlequin takes it a bit more seriously than Franz.

  this is _very_ difficult to establish from watching the products, as it
  refers to intentions and future, not to the past.  it _is_ fair to say
  that Harlequin's LispWorks conforms better to the specification in some
  areas than Franz's Allegro CL does, but it has to be an area-by-area
  comparison to be fair, and the severity of the non-conformance is also
  important for a fair comparison.  e.g., _my_ impression is that Allegro
  CL has a weaker safe mode (not all errors signal errors as they should)
  than one could hope for, but this is not an area where I need it, so it
  may or may not matter to a particular programmer.  (incidentally, I know
  that Franz Inc _is_ taking conformance seriously and I'm working with
  them to help us all get there.)

| Harlequin seems to be much better at supporting Unicode and other
| character sets.

  although very valuable for a user, this is not about conformance to the
  ANSI Common Lisp standard.  it is therefore important to state what you
  expect from a product.

| Franz still seems to think that 256 characters is more than enough (just
| like Bill Gates thought that 640K is more than anyone would ever need).

  such parenthetical remarks, however, make your "comparison" nigh useless.

  incidentally, Franz Inc has an "international" (= Japanese) version that
  covers the need of most present non-Latin speakers.  (I have had to do a
  little home-brewing to get ISO 8859-1 working as I want it to in Allegro
  CL, but I don't know whether LispWorks is any better.)
| * Integration with underlying platform

  this is a valuable comment to a user.

| * Performance

  comparisons here are fraught with danger and should be performed with
  published code and all sorts of things.  e.g., some property that makes
  it feel "sluggish" could be extremely easy to fix, and other properties
  can be very hard to change because they are pandemic to the design.  I
  think performance comparisons are _generally_ unfair, because after you
  have decided on a product, you learn how to make it faster.

| I'll be happy to have my impressions corrected by people who know
| better.

  I don't want to snap at you, but it's a _lot_ safer to talk to the person
  requesting a comparison and let it be a personal exchange, rather than
  post impressions and request correction; it usually requires a huge
  effort to correct simple misimpressions.  this is why comparisons often
  produce a tremendous amount of noise on the newsgroups.  also, most user
  impressions are exceedingly hard to quantify, and a lot of factors come
  into play.

  incidentally, I haven't had the opportunity to compare Allegro CL with
  much anything else.  (I went from CMUCL 17f to Allegro CL 4.3 and it was
  a world of difference, so I don't even consider CMUCL possible to compare
  in the area I think matters the most: the development environment.)  I
  get the performance I need, and I get the support I need from Franz Inc
  whenever I wonder about something or find a problem, and I see no reason
  to go look for a competing product.  now, this is more an accident of
  history than anything else, so it does in no way preclude similar
  experiences with Harlequin -- it just didn't happen to me.  my guess is
  that this is how most user impressions are formed: luck and good timing.

environmentalists are much too concerned with planet earth.  their geocentric
attitude prevents them from seeing the greater picture -- lots of planets are
much worse off than earth is.