Call for Interest: Clojure (or Lisp?) Code Camp with BLM focus

Scott McKay swmckay at
Thu Dec 3 13:04:48 UTC 2020

Super interesting, thanks for that!


On Thu, Dec 3, 2020 at 8:00 AM Pascal Costanza <pc at> wrote:

> This was primarily for the lack of good parallel, concurrent garbage
> collectors in Common Lisp implementations. The CL version of elPrep was
> actually still a tad faster than any of the C++, Go, or Java versions, but
> we had to work hard to avoid long GC pauses. elPrep allocates a lot of
> memory, and the pause time hurts a lot. We solved this by, basically,
> disabling the garbage collector, and reusing memory manually as much as
> possible, which turned the program into almost a manually memory-managed
> affair.
> Manual memory management became a huge burden because we wanted to add
> more and more components to the software, and then it becomes almost
> impossible to predict object lifetimes.
> We evaluated Go and Java for their concurrent, parallel GCs, and C++ for
> its reference counting. Interestingly, reference counting is often
> described as more efficient than GC, but in our case that’s not true:
> Because there is a huge object graph at some stage that needs to be
> deallocated, reference counting incurs more or less the same pause that a
> non-concurrent GC does. That’s why we don’t expect Rust to fare better here
> either.
> Again, we’re still prototyping in Common Lisp, which is a huge win,
> because this makes us much more productive.
> Pascal
> > On 3 Dec 2020, at 12:16, Svante Carl v. Erichsen <
> svante.v.erichsen at> wrote:
> >
> > Hi!
> >
> > I vaguely remember having read that you do that.  I'm still wondering
> > why, though.  I guess that you wrote about it, but I can't find it right
> > now.
> >
> > So, if it's not because Common Lisp is not seen as “production ready”,
> > why rewrite instead of just adding the production parts (I guess
> > hardening, monitoring, logging, documentation etc.)?
> >
> > Yours aye
> >
> > Svante
> >
> >
> > Pascal Costanza writes:
> >
> >> In my opinion, prototyping in Common Lisp, and then translating to a
> >> different programming language for creating the final product, is a
> >> perfectly valid professional use of Common Lisp. It’s useful to know
> >> which programming languages may be good targets for such an approach.
> >>
> >> This is, of course, not ideal, because this can easily be
> >> misunderstood as a statement that Common Lisp is not fit for
> >> purpose. However, I don’t see it that way, and you cannot control
> >> people’s perceptions.
> >>
> >> In our particular case, our manager is on board with this approach,
> >> and this allows us to pay for regular licenses for LispWorks. The
> >> approach works really well for us.
> >>
> >> Pascal
> >>
> >> Sent from my iPad
> >>
> >>> On 3 Dec 2020, at 05:29, Dave Cooper <david.cooper at>
> wrote:
> >>>
> >>> 
> >>>
> >>>> Where else do Common Lispers go to talk shop, whether CL or something
> else?
> >>>
> >>>
> >>> To me, Common Lispers "talking shop" by definition means talking about
> CL or related topics, not an open-ended "something else." I would turn that
> question around and ask "where else do Common Lispers go for unapologetic
> mutual support for their chosen or imposed computing platform, which is
> Common Lisp?"  If groups such as this mailing list become diluted with hand
> wringing, naysaying, and negativity, then you tell me Tim, where do actual
> Common Lispers go?
> >>>
> >>>
> >>>> CL is very good but it is not perfect.  Debating the relative merits
> of
> >>>> various languages can lead to cross-pollination of ideas.  It appears
> that
> >>>> most innovation is happening elsewhere, and I hope this community can
> >>>> bring the best of CL into a worthy successor, whatever it may be
> called.
> >>>>
> >>>
> >>> If "most innovation is happening elsewhere" then those of us who have
> the propensity to look into other languages can serve the community here by
> reporting back the cool things they find and discussing how we may or may
> not be able to co-opt such things into CL. If such is the perspective and
> purpose of "debating the merits of various languages," then indeed, such
> debate can result in productive cross-pollination, and this is needed and
> wanted.
> >>>
> >>> If the intention and focus is instead to sing the praises of other
> environments in order to seek fellow converts or validation for converting,
> and doing this while specifically targeting a group set up to support
> "professional common lispers," then I consider such efforts to be unhelpful
> in the context of this group and I would invite you to take such
> discussions into the forums of those other environments or into some
> general language discussion forums.
> >>>
> >>> Understand that not all of us have the "luxury" on the one hand, nor
> the desire on the other hand, to chase the dragon of the latest cool thing,
> and we look to groups such as this one specifically to support our crusty
> old entrenched mentality -- and to improve our environment as best we can,
> understanding the inherent limitations that exist. This is the life we have
> chosen.
> >>>
> >>>
> >
> >
> --
> Pascal Costanza
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