- pro - mailman3.common-lisp.net

Advice sought on structuring a system
by Don Morrison 12 Apr '16

12 Apr '16

I'm tidying up a library of code, Roan (for building things that play with change ringing, you probably don't want to know the details :-), for eventual inclusion in Quicklisp. In thinking about its dependencies I've run into an issue I'm not sure how best to address. I asked Zach Beane for advice, but he, too, isn't sure how best to deal with it, and suggested I consult folks on this list. My library has dependencies upon several others, all readily available from Quicklisp. One them, though, cl-sqlite (or perhaps it's better referred to as sqlite, it's rather conflicted about what it wants to call itself) in turn has a dependency on a binary library, sqlite3. For example, if the sqlite3 binary library is not install, doing (ql:quickload :sqlite) signals an error when it's setting up FFI things. However Roan's use of SQLite is not essential to Roan's usefulness (well, it's probably not all that useful to most people anyway, only to those interested in change ringing, a small audience). There's really only one, tiny corner of functionality in Roan it supports. While sqlite3 is easily obtained, it would seem polite to allow use of Roan without it, simply disabling the two functions that depend upon it. The "disable if the cl-sqlite stuff is not present" part I can easily do. What's causing me to scratch my head is figuring out how to set things up so Roan will still install whether or not the sqlite3 binary library is present. Three unattractive possibilities that come to mind are - Define two different roan ASDF systems: one consisting of most stuff, without the SQLite-dependent bits, and the other the "real" one that loads the first plus cl-sqlite. Then the user picks which one to load based on need. - Define something to push onto *features* that, if present, comments out in roan.asd the dependency on cl-sqlite, etc. Then the user has to push the appropriate keyword onto *features* before loading roan, if she doesn't have sqlite3. - I'm guessing I could probably include some code in the roan.asd file that does something or other nasty looking for the binary library, and then adjusts the defsystem appropriately or something (ugh). None of these is particularly appealing. The first two seem to put too much on the shoulders of the poor luser who just wants to load the darn thing without having to think about lower level stuff, and the last (a) seems to confound too much actually doing complex, kludgy stuff with what should be just declarative, and (b) is something I seriously doubt I'd get right, especially in a portable way. It seems there has got to be A Better Way. Has anyone dealt with a similar situation? Or, even if not, might you have a good idea? I suppose an attractive possibility might be to wrap some sort of condition handler around the place inside ASDF that's trying to load the cl-sqlite dependency, but I don't know my way around the ASDF internals enough to have a sense of where that should be done, or if it's even practical. Is there a good place inside of ASDF to do such a thing? It seems fairly modular, so it seems likely. Maybe it's as easy as defining a specialized method of some sort, or an :around method on something or other? Thanks! -- Don Morrison <dfm2(a)cmu.edu> "There were two cultures, as far as he was concerned. One was the real one, the other was occupied by people who liked machinery and ate pizza at unreasonable hours." -- Terry Pratchett, _The Last Hero_

10 12

[CFPart] ELS'16, 9th European Lisp Symposium, May 9-10, Kraków, Poland
by Didier Verna 06 Apr '16

06 Apr '16

ELS'16 - 9th European Lisp Symposium Department of Computer Science AGH University of Science and Technology Kraków, Poland May 9-10, 2016 In cooperation with: ACM SIGPLAN Sponsored by EPITA, Franz Inc., LispWorks Ltd., IdEx and Dept. of Computer Science AGH UST http://www.european-lisp-symposium.org/ Recent news: - Full programme now available online - Registration now open (early registration deadline: April 25) The purpose of the European Lisp Symposium is to provide a forum for the discussion and dissemination of all aspects of design, implementation and application of any of the Lisp and Lisp-inspired dialects, including Common Lisp, Scheme, Emacs Lisp, AutoLisp, ISLISP, Dylan, Clojure, ACL2, ECMAScript, Racket, SKILL, Hop and so on. We encourage everyone interested in Lisp to participate. Keynote speakers: - Pierre Castéran -- Program Proving with Coq - Stephan Karpinski -- Julia: to Lisp or Not to Lisp? - Francis Sergeraert -- Lexical Closures and Complexity Important dates: - 25 Apr 2016 Early registration deadline - 9-10 May 2016 Symposium Programme chair: Irène Durand, LaBRI, University of Bordeaux, France Local chair: Michał Psota, Emergent Network Defense, Kraków, Poland Programme committee: Antonio Leitao — INESC-ID / Instituto Superior Técnico, Universidade de Lisboa, Portugal Charlotte Heerzel — IMEC, Leuven, Belgium Christian Queinnec — University Pierre et Marie Curie, Paris 6, France Christophe Rhodes — Goldsmiths, University of London, United Kingdom Didier Verna — EPITA Research and Development Laboratory, France Erick Gallesio — University of Nice-Sophia Antipolis, France François-René Rideau, Google, USA Giuseppe Attardi — University of Pisa, Italy Kent Pitman, HyperMeta Inc., USA Leonie Dreschler-Fischer — University of Hamburg, Germany Pascal Costanza — Intel Corporation, Belgium Robert Strandh — University of Bordeaux, France Search Keywords: #els2016, ELS 2016, ELS '16, European Lisp Symposium 2016, European Lisp Symposium '16, 9th ELS, 9th European Lisp Symposium, European Lisp Conference 2016, European Lisp Conference '16 -- Resistance is futile. You will be jazzimilated. Lisp, Jazz, Aïkido: http://www.didierverna.info

1 0

[CfP] ELS 2016 Deadline extension: Sat Feb 27
by Didier Verna 20 Feb '16

20 Feb '16

ELS'16 - 9th European Lisp Symposium Department of Computer Science AGH University of Science and Technology Kraków, Poland May 9-10, 2016 In cooperation with: ACM SIGPLAN Sponsored by EPITA, Franz Inc., LispWorks Ltd., IdEx and Dept. of Computer Science AGH UST http://www.european-lisp-symposium.org/ Recent news: - *** Submission deadline extended to Saturday Feb 27 *** The purpose of the European Lisp Symposium is to provide a forum for the discussion and dissemination of all aspects of design, implementation and application of any of the Lisp and Lisp-inspired dialects, including Common Lisp, Scheme, Emacs Lisp, AutoLisp, ISLISP, Dylan, Clojure, ACL2, ECMAScript, Racket, SKILL, Hop and so on. We encourage everyone interested in Lisp to participate. The 9th European Lisp Symposium invites high quality papers about novel research results, insights and lessons learned from practical applications and educational perspectives. We also encourage submissions about known ideas as long as they are presented in a new setting and/or in a highly elegant way. Topics include but are not limited to: - Context-, aspect-, domain-oriented and generative programming - Macro-, reflective-, meta- and/or rule-based development approaches - Language design and implementation - Language integration, inter-operation and deployment - Development methodologies, support and environments - Educational approaches and perspectives - Experience reports and case studies We invite submissions in the following forms: Papers: Technical papers of up to 8 pages that describe original results or explain known ideas in new and elegant ways. Demonstrations: Abstracts of up to 2 pages for demonstrations of tools, libraries, and applications. Tutorials: Abstracts of up to 4 pages for in-depth presentations about topics of special interest for at least 90 minutes and up to 180 minutes. The symposium will also provide slots for lightning talks, to be registered on-site every day. All submissions should be formatted following the ACM SIGS guidelines and include ACM classification categories and terms. For more information on the submission guidelines and the ACM keywords, see: http://www.acm.org/sigs/publications/proceedings-templates and http://www.acm.org/about/class/1998. The conference proceedings will be published in the ACM Digital Library. Important dates: - *** EXTENDED *** 27 Feb 2016 Submission deadline *** EXTENDED *** - 25 Mar 2016 Notification of acceptance - 15 Apr 2016 Early registration deadline - 22 Apr 2016 Final papers due - 9-10 May 2016 Symposium Programme chair: Irène Durand, LaBRI, University of Bordeaux, France Local chair: Michał Psota, Emergent Network Defense, Kraków, Poland Programme committee: Antonio Leitao — INESC-ID / Instituto Superior Técnico, Universidade de Lisboa, Portugal Charlotte Heerzel — IMEC, Leuven, Belgium Christian Queinnec — University Pierre et Marie Curie, Paris 6, France Christophe Rhodes — Goldsmiths, University of London, United Kingdom Didier Verna — EPITA Research and Development Laboratory, France Erick Gallesio — University of Nice-Sophia Antipolis, France François-René Rideau, Google, USA Giuseppe Attardi — University of Pisa, Italy Henry Lieberman — MIT, USA Kent Pitman, HyperMeta Inc., USA Leonie Dreschler-Fischer — University of Hamburg, Germany Pascal Costanza — Intel Corporation, Belgium Robert Strandh — University of Bordeaux, France Search Keywords: #els2016, ELS 2016, ELS '16, European Lisp Symposium 2016, European Lisp Symposium '16, 9th ELS, 9th European Lisp Symposium, European Lisp Conference 2016, European Lisp Conference '16 -- Resistance is futile. You will be jazzimilated. Lisp, Jazz, Aïkido: http://www.didierverna.info

1 0

Naming suggestions
by Antoniotti Marco 05 Feb '16

05 Feb '16

Dear all, in the quest for RESTHBDB) RE-doing Stuff That Has Been Done Before) I am trying to come up with a name for a referencing/dereferencing operator. Think of something like (<name-of-reference-operator> #2A((1 0) (0 1)) 0 0) ==> 1 of (<name-of-reference-operator> #H((foo . bar) (we . 42)) ‘foo) ==> BAR ; I am cheating. #H(..) is a hash table. SETF methods will be defined as expected. Now. What could be a good name? I have the following list. REF REF$ [] [[]] AT @ GETAT What do you think? (Full disclosure: I usually refrain from taking up non alphabetic names) Cheers MA -- Marco Antoniotti, Associate Professor tel. +39 - 02 64 48 79 01 DISCo, Università Milano Bicocca U14 2043 http://bimib.disco.unimib.it Viale Sarca 336 I-20126 Milan (MI) ITALY Please check: http://cdac.lakecomoschool.org Please note that I am not checking my Spam-box anymore. Please do not forward this email without asking me first.

10 11

[CfP] 9th European Lisp Symposium, May 9-10, Krakow, Poland
by Didier Verna 21 Jan '16

21 Jan '16

ELS'16 - 9th European Lisp Symposium Department of Computer Science AGH University of Science and Technology Kraków, Poland May 9-10, 2016 In cooperation with: ACM SIGPLAN Sponsored by EPITA, Franz Inc., LispWorks Ltd. and Dept. of Computer Science AGH UST http://www.european-lisp-symposium.org/ Recent news: - Submission deadline in less than a month! - 3nd invited speaker announced: Stephan Karpinski on Julia: to Lisp or Not to Lisp? The purpose of the European Lisp Symposium is to provide a forum for the discussion and dissemination of all aspects of design, implementation and application of any of the Lisp and Lisp-inspired dialects, including Common Lisp, Scheme, Emacs Lisp, AutoLisp, ISLISP, Dylan, Clojure, ACL2, ECMAScript, Racket, SKILL, Hop and so on. We encourage everyone interested in Lisp to participate. The 9th European Lisp Symposium invites high quality papers about novel research results, insights and lessons learned from practical applications and educational perspectives. We also encourage submissions about known ideas as long as they are presented in a new setting and/or in a highly elegant way. Topics include but are not limited to: - Context-, aspect-, domain-oriented and generative programming - Macro-, reflective-, meta- and/or rule-based development approaches - Language design and implementation - Language integration, inter-operation and deployment - Development methodologies, support and environments - Educational approaches and perspectives - Experience reports and case studies We invite submissions in the following forms: Papers: Technical papers of up to 8 pages that describe original results or explain known ideas in new and elegant ways. Demonstrations: Abstracts of up to 2 pages for demonstrations of tools, libraries, and applications. Tutorials: Abstracts of up to 4 pages for in-depth presentations about topics of special interest for at least 90 minutes and up to 180 minutes. The symposium will also provide slots for lightning talks, to be registered on-site every day. All submissions should be formatted following the ACM SIGS guidelines and include ACM classification categories and terms. For more information on the submission guidelines and the ACM keywords, see: http://www.acm.org/sigs/publications/proceedings-templates and http://www.acm.org/about/class/1998. The conference proceedings will be published in the ACM Digital Library. Important dates: - 19 Feb 2016 Submission deadline - 25 Mar 2016 Notification of acceptance - 15 Apr 2016 Early registration deadline - 22 Apr 2016 Final papers due - 9-10 May 2016 Symposium Programme chair: Irène Durand, LaBRI, University of Bordeaux, France Local chair: Michał Psota, Emergent Network Defense, Kraków, Poland Programme committee: Antonio Leitao — INESC-ID / Instituto Superior Técnico, Universidade de Lisboa, Portugal Charlotte Heerzel — IMEC, Leuven, Belgium Christian Queinnec — University Pierre et Marie Curie, Paris 6, France Christophe Rhodes — Goldsmiths, University of London, United Kingdom Didier Verna — EPITA Research and Development Laboratory, France Erick Gallesio — University of Nice-Sophia Antipolis, France François-René Rideau, Google, USA Giuseppe Attardi — University of Pisa, Italy Henry Lieberman — MIT, USA Kent Pitman, HyperMeta Inc., USA Leonie Dreschler-Fischer — University of Hamburg, Germany Pascal Costanza — Intel Corporation, Belgium Robert Strandh — University of Bordeaux, France Search Keywords: #els2016, ELS 2016, ELS '16, European Lisp Symposium 2016, European Lisp Symposium '16, 9th ELS, 9th European Lisp Symposium, European Lisp Conference 2016, European Lisp Conference '16 -- @-quartet live: Sunset/Sunside, Paris, Jan 26 2016 ! Book now: http://www.sunset-sunside.com/2016/1/artiste/2101/3453/ Lisp, Jazz, Aïkido: http://www.didierverna.info

1 0

Package extensions usage
by Alessio Stalla 06 Jan '16

06 Jan '16

Hi everyone, I'd like to run a little poll among experienced Lisp developers. The topic is the usage in the wild of the extensions to the package system provided by various implementations. My apologies to people who are subscribed to the ABCL mailing list, where some time ago I submitted the same questions getting back several insightful answers but no actual data. So, here is how it is. I'm working on a novel idea (I hope) regarding symbols and packages; I won't go into the details now. It suffices to say that there is some overlap with features offered by certain Lisp implementations, namely: * package-local nicknames: the ability to specify, for each package, a list of nicknames for other packages which are in effect only in that package; available on ABCL and SBCL ( http://www.sbcl.org/manual/#Package_002dLocal-Nicknames) and possibly other implementations I'm not aware of. * "Hierarchical" packages: a naming convention for packages understood by the reader and a few support functions, which allow to have concise nicknames for a group of closely related packages, such as com.foo.mylib.api and com.foo.mylib.implementation. Found natively in Allegro CL (http://franz.com/support/documentation/current/doc/packages.htm) and in an open-source library by P. Bourguignon. My questions: 1) First and foremost, is anybody actually using those features? What are you using them for? 2) If yes, how useful are they for you? What shortcomings do you find in them?

13 18

[CfP] European Lisp Symposium 2016, May 9-10, Kraków, Poland
by Didier Verna 07 Oct '15

07 Oct '15

ELS'16 - 9th European Lisp Symposium AGH University of Science and Technology Kraków, Poland May 9-10, 2016 http://www.european-lisp-symposium.org/ Sponsored by EPITA and AGH University The purpose of the European Lisp Symposium is to provide a forum for the discussion and dissemination of all aspects of design, implementation and application of any of the Lisp and Lisp-inspired dialects, including Common Lisp, Scheme, Emacs Lisp, AutoLisp, ISLISP, Dylan, Clojure, ACL2, ECMAScript, Racket, SKILL, Hop and so on. We encourage everyone interested in Lisp to participate. The 9th European Lisp Symposium invites high quality papers about novel research results, insights and lessons learned from practical applications and educational perspectives. We also encourage submissions about known ideas as long as they are presented in a new setting and/or in a highly elegant way. Topics include but are not limited to: - Context-, aspect-, domain-oriented and generative programming - Macro-, reflective-, meta- and/or rule-based development approaches - Language design and implementation - Language integration, inter-operation and deployment - Development methodologies, support and environments - Educational approaches and perspectives - Experience reports and case studies We invite submissions in the following forms: Papers: Technical papers of up to 8 pages that describe original results or explain known ideas in new and elegant ways. Demonstrations: Abstracts of up to 2 pages for demonstrations of tools, libraries, and applications. Tutorials: Abstracts of up to 4 pages for in-depth presentations about topics of special interest for at least 90 minutes and up to 180 minutes. The symposium will also provide slots for lightning talks, to be registered on-site every day. All submissions should be formatted following the ACM SIGS guidelines and include ACM classification categories and terms. For more information on the submission guidelines and the ACM keywords, see: http://www.acm.org/sigs/publications/proceedings-templates and http://www.acm.org/about/class/1998. Important dates: - 19 Feb 2016 Submission deadline - 25 Mar 2016 Notification of acceptance - 15 Apr 2016 Early registration deadline - 22 Apr 2016 Final papers due - 9-10 May 2016 Symposium Programme chair: Irène Durand, University of Bordeaux, France Local chair: Michał Psota, Emergent Network Defense, Kraków, Poland Programme committee: Antonio Leitao — INESC-ID / Instituto Superior Técnico, Universidade de Lisboa, Portugal Charlotte Heerzel — IMEC, Leuven, Belgium Christian Queinnec — University Pierre et Marie Curie, Paris 6, France Christophe Rhodes — Goldsmiths, University of London, United Kingdom Didier Verna — EPITA Research and Development Laboratory, France Erick Gallesio — University of Nice-Sophia Antipolis, France Francois-René Rideau, Google, USA Giuseppe Attardi — University of Pisa, Italy Henry Lieberman — MIT, USA Kent Pitman, HyperMeta Inc., U.S.A. Leonie Dreschler-Fischer — University of Hamburg, Germany Pascal Costanza — Intel Corporation, Belgium Robert Strandh — University of Bordeaux, France Search Keywords: #els2016, ELS 2016, ELS '16, European Lisp Symposium 2016, European Lisp Symposium '16, 9th ELS, 9th European Lisp Symposium, European Lisp Conference 2016, European Lisp Conference '16 -- My new Jazz CD entitled "Roots and Leaves" is out! Check it out: http://didierverna.com/records/roots-and-leaves.php Lisp, Jazz, Aïkido: http://www.didierverna.info

1 0

Erlang style processes in Common Lisp
by shenanigans＠sonic.net 27 Sep '15

27 Sep '15

Creators of Erlang have a Lisp background, and one feature of the Erlang VM (BEAM) that I'd like back-ported into Common Lisp is their process. An Erlang "process" is cheap to create, cheap to destroy, cheap when blocked, and upon exit performs bulk gc of its allocated memory; e.g., munmap(). Handling tens of thousands of requests per second per node isn't uncommon, and these often have *several* workers per request or connection: hundreds of thousands of processes. Under such scenarios, anything less than this approach to lightweight processes might suffer from stalls during long gc runs that would be avoided or significantly reduced under Erlang's model. How might we get equivalent cheap ephemeral processes into a contemporary Common Lisp implementation? For those unfamiliar with it, what Erlang means by "process" stems from an implementation of Actor Model with caveats. Each process is more co-routine than thread, and many may run within the same OS thread managed by the Erlang scheduler. The BEAM VM pre-empts processes via "reduction" counting, which may be understood as unit of VM time. Their famed tag line, "Let it crash," may be loosely understood in CL terms as an implicit HANDLER-CASE. The open question here is to address a stated non-goal of CL-MUPROC, "we rely on the CL implementation's MP system" and "considerably heavier than Erlang processes". [See presentation link from https://common-lisp.net/project/cl-muproc/ ] Some Erlang-on-CL packages use OS threads or in the case of Erlang-in-Lisp, fork(). While easier for a library author to implement, these contradict the definition of cheap here. Other such packages punt the issue altogether and instead focus only on pattern-matching aspects of Erlang the language. Then there's Lisp-Flavoured-Erlang, and Elixir offers hygienic macros that manipulate the full AST properly-- all play nice on same Erlang VM at runtime-- for people simply looking to avoid Erlang syntax or semantics. But let's focus on cheap Erlang style processes in Common Lisp here, please. 1. Semantics of library elements are straight-forward enough (e.g., SPAWN, EXIT) and may be borrowed wholesale and safely named within their own package. 2. Memory allocation & garbage collection: Erlang BEAM VM doesn't begin to reclaim memory until very late, so an initial implementation here might assume ephemeral worker processes and omit gc until exit of a worker. However, some processes are long-lived in practice. One compromise might be acceptable: one nursery per process, but anything promoted to higher generations gets handled however your gc does it now. This states nothing about use of shared versus multiple heaps across OS threads, so such matters may continue to be implementation-dependent. 3. Co-routines: For something similar to Erlang's reductions, there would need to be a measure of runtime complexity per process. However, I've used single thread co-routines for near realtime systems in C and CL with a loop of function pointers and ensuring that each referenced function executes under some threshold determined through experimentation and confirmed via test cases. No pre-empting needed. While fragile and not easily portable across different hardware (including same architecture), this may be acceptable for a preliminary draft. Using CL-MUPROC routines as an example and extending MUPROCN: perhaps its body becomes this top-level list of functions from which interleaving across processes may occur. Then add variations for playing well with DO or LOOP semantics. 4. Message-passing: SBCL's sb-concurrency extension with Queue and Mailbox (implementation of "Optimistic FIFO Queue") can be the solution here too. More aligned with CL principles, allowing for multiple mailboxes-- and therefore priority messaging-- would be a welcome advancement beyond Erlang. (Erlang allows only one mailbox per process: sequential but with pattern matching, nothing out-of-band...) An important implementation detail that simplifies gc and increases cache locality across NUMA nodes: messages get duplicated when delivered-- each process only references its own copy! 5. (Almost) nothing shared: Erlang enforces strict prohibition against shared memory, and common practice is to use an in-memory database (ETS) as key/value store in lieu of globals. Scala allows but discourages shared memory. A CL-inspired take on this might be to use SBCL's approach with thread creation: upon creating a new process, you get: A) global special values, but modify at own risk... B) LET bindings are local to each process; C) threads don't inherit dynamic bindings from parent. i.e., http://sbcl.org/manual/index.html#Special-Variables 6. Scheduling processes on OS threads: This is delicate in Erlang, and I've experienced specialized use cases interfering with their scheduler when under heavy load. Instead for our purposes, let the programmer handle the mapping of processes to OS threads. Less is more here. 7. Finally, gen_server & OTP fiends may be implemented as their own packages... or skipped entirely! Thoughts on feasibility? Thanks, -Daniel

11 20

Conditions and *PRINT-READABLY*
by Edi Weitz 07 Sep '15

07 Sep '15

Hi everybody! With the code at the end of this mail I would have expected an outcome similar to this one R: T , E: T - [REFUSED TO PRINT] R: T , E: NIL - [REFUSED TO PRINT] R: NIL, E: T - #<MY-CONDITION 20098B07> R: NIL, E: NIL - My condition occured. because the standard says that "if *PRINT-READABLY* is true, printing proceeds as if *PRINT-ESCAPE* were also true." This would mean that the first two lines should look the same because the value of *PRINT-ESCAPE* is irrelevant in this case. However, while this is what happens for example with LispWorks, AllegroCL, and CLISP, in some other Lisps like SBCL, CCL, and ECL the second line looks like the fourth. Isn't that wrong? Or is their interpretation of the standard that the report function is responsible for obeying *PRINT-READABLY*? But how does that fit with the possibility of using strings for :REPORT? Thanks, Edi. (define-condition my-condition () () (:report "My condition occured.")) (defun test () (let ((error (make-condition 'my-condition))) (dolist (readably '(t nil)) (dolist (escape '(t nil)) (format t "~&R: ~3A, E: ~3A - " readably escape) (handler-case (write error :readably readably :escape escape) (print-not-readable () (write-string "[REFUSED TO PRINT]")))))))

3 2

PRINT-OBJECT for built-in classes
by Edi Weitz 29 Aug '15

29 Aug '15

The following "works" in three different CL implementations I tried while in three others the way complex numbers are printed doesn't change. ? (defmethod print-object ((obj complex) stream) (format stream "#< ~A + ~A * I >" (realpart obj) (imagpart obj))) #<STANDARD-METHOD PRINT-OBJECT (COMPLEX T)> ? #c(1 1) #< 1 + 1 * I > My understanding of 22.1.2 of the standard is that each Lisp MUST have a PRINT-OBJECT method for complex numbers. The question then is whether I'm allowed to redefine it like above (I think I am) and/or whether an implementation is allowed to accept this redefinition without a warning but then to ignore it (which, as I said, is what happens in three respectable Lisps). Thanks, Edi. [Note: There's no point in talking me out of this as I don't actually want to do it anyway. It's just an example and I'm only interested in what exactly is governed by the standard. Complex numbers are also just an example. I'm interested in PRINT-OBJECT for built-in classes in general.]

5 5