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Didier Verna's scientific blog: Lisp, Emacs, LaTeX and random stuff.

Wednesday, December 13 2017

Announcing Quickref: a global documentation project for Common Lisp

Today, we deployed the first version of Quickref, a new global documentation project for Common Lisp.

The purpose of Quickref is to provide a centralized collection of reference manuals for the whole Quicklisp world. This means around 1500 libraries, for a total of around 3000 ASDF systems. The reference manuals are generated by Declt, which is probably the most complete documentation system for Common Lisp currently available, and delivered in HTML (PDF versions could easily be made available as well).

A lot of things can still be improved, but I'm pretty satisfied with the result so far. 3000 ASDF systems is a hell of a test suite for Declt, and I'm happy to report that it passes on practically all of them. Only a couple of issues remain, not even due to Declt itself, and less than a dozen or so libraries still pose problems (mostly technical difficulties due to foreign dependencies).

Quickref was made by Antoine Martin, as part of an internship with me. Many thanks to him! We still have some cleanup and packaging to do, but we expect to open-source the infrastructure soon. I also want to thank Mark Evenson, Erik Huelsmann and the Common Lisp Foundation for hosting the project on common-lisp.net (it was only natural)!

Finally, let me restate this again (and again): reference manuals are not user manuals. They are... reference manuals. Although automatically generated, there are some things you can do, as a library author, to improve the output (this is an area of Declt which I intend to work on in the future). Please refer to the Declt user manual (notably section 3.2 Coding Style) for more information.

Friday, October 27 2017

Standard IO syntax and the Robustness Principle

Here is a flagrant illustration of the robustness principle, or rather, of a failure to honor it.

I was investigating a bug in Declt where some floating point numbers were printed with exponent markers (e.g. 0.5f0 instead of just 0.5) in the Texinfo file, which broke the parsing of the file by Perl.

Eventually, I found out a double infringement of the robustness principle. First of all, Declt failed to comply with part 1 of the robustness principle: be lenient with the others. The Texinfo file generation routine should have been wrapped into a call to WITH-STANDARD-IO-SYNTAX and it wasn't. Always do that to be on the safe side. Lesson learnt.

This failure on my part, however, had the interesting consequence of exhibiting what I consider a serious infringement of part 2 of the robustness principle: be strict with yourself. It would have remained unnocited otherwise. The culprit here is not Declt. This time, it's the common-lisp-stat library. Problem: the simple fact of loading this library globally changes the value of *READ-DEFAULT-FLOAT-FORMAT* from SINGLE-FLOAT (the default) to DOUBLE-FLOAT. This is bad, and it can break your code in all sorts of nasty ways.

Explanation

*READ-DEFAULT-FLOAT-FORMAT* tells the reader how to read floats when no exponent marker is provided. By default, 0.5 will be read as a SINGLE-FLOAT. But this variable also influences the printer (out of a concern for printing readably I guess): when printing a float of a different format than the current default, then the appropriate exponent marker is also printed. So here is precisely what happened. Declt had been compiled with some floats (e.g. 0.5) read as SINGLE-FLOATs. Later on, those floats were supposed to be printed aesthetically as such. But right after loading common-lisp-stat, the default format changed to DOUBLE-FLOAT and all of a sudden 0.5 started to be printed as 0.5f0.

Consequences

This is bad enough already, but consider that messing with the standard IO syntax globally like this can break your code in all other sorts of even nastier ways. Imagine for instance that common-lisp-stat had been loaded before Declt, and Declt needed to be recompiled. All of a sudden, Declt would be using double floats and the bug would be gone. That is, until the next start of the REPL, after which all floats would be printed like 0.5d0!

So granted, my code wasn't robust enough. But please, don't mess with standard IO syntax globally!

Monday, October 16 2017

Declt 2.3 "Robert April" is out

I'm happy to announce the release of Declt 2.3. Declt is my reference manual generator for Common Lisp libraries.

The improvements and bug fixes in the last two releases are the result of running Declt against the whole Quicklisp world (around 3000 ASDF systems for 1500 libraries). See this post for more information.

New in this release:

  • Advertise file extensions in references.
  • Advertise the type of foreign definitions.
  • More robust display and indexing of, and with, lambda-lists.
  • Use UTF8 special characters to denote invisble ones.
  • More robust support for Texinfo brace escaping.
  • Handle modules sharing the same location.
  • Ensure output is done with standard IO syntax.
  • Fix potential duplication of some (non-lisp) files and document all static files.
  • Fix potential duplication of packages documentation.

From the 2.2 "Christopher Pike" release (not previously advertised):

  • Require a UTF-8 environment.
  • Understand ASDF's notion of inferred system, and also be more protective against ASDF extensions.
  • Support for improper lambda lists (e.g. destructuring ones).
  • Improve contact defaulting code.
  • Update support for SBCL's setf expanders introspection.
  • Accept ASDF system designators.
  • Various bug fixes in the areas of method combinations, accessor definition merging and setf expanders.

Find it at the usual place...

Sunday, March 5 2017

FiXme 4.4 is out

I'm pleased to announce the release of FiXme 4.4 (my collaborative annotation tool for LaTeX).

New in this release:

** Handle existing yet empty lox files properly
meaning, don't actually typeset an empty list of corrections.
** Don't update the lox file in final mode
avoiding potential typesetting artifacts, reported by Lars Madsen.
** Various internals and documentation improvements.

Get it at the usual place.

Tuesday, February 28 2017

Declt 2.1 "Jonathan Archer" is out

I'm happy to announce the release of Declt 2.1 "Jonathan Archer".

New in this release:

  • Handle recent change in SBCL's SB-INT:INFO API.
  • Handle list of contacts (strings) in ASDF systems author and maintainer slots.
  • Some backward-incompatible changes in the keyword arguments to the DECLT function.
  • More hyperlinks between systems and source files.
  • More robust system's packages collection (no more code walking).
  • More robust handling of unavailable ASDF components.
  • More robust naming of cross-references.

Find it at the usual place...

Thursday, January 26 2017

DoX 2.3 is out

I'm pleased to announce the release of DoX 2.3 (Extensions to the Doc pakcage for LaTeX).

New in this release:

** Support Doc's internal \saved@indexname command
thanks to Falk Hanisch.

Get it at the usual place.

Wednesday, January 18 2017

FiXme 4.3 is out

I'm pleased to announce the release of FiXme 4.3 (my collaborative annotation tool for LaTeX), after more than 3 years of hyper-sleep.

New in this release:

** Add a paragraph about the duplication of notes in captions
upon exchange with Kreuvf.
** Update support for the KOMA-Script classes to the tocbasic interface
reported by Dirk Surmann.
** Separate inline notes from the text they follow
suggested by Victor Porton.
** Fix potential inline layouts color leakage
reported by Victor Porton.
** Fix several bracket parsing problems
thanks to Joseph Wright and Lars Madsen.

Get it at the usual place.

Monday, November 7 2016

10th European Lisp Symposium, April 3-4 2017, Brussels, Belgium

		ELS'17 - 10th European Lisp Symposium

		   VUB - Vrije Universiteit Brussel
			       Belgium

			   April 3-4, 2017

		In co-location with <Programming> 2017
		  Sponsored by Brunner Software GmbH

	       http://www.european-lisp-symposium.org/


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 10th 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.

Submissions should be uploaded to Easy Chair, at the following address:
https://www.easychair.org/conferences/?conf=els17

Note: to help us with the review process please indicate the type of
submission by entering either "paper", "demo", or "tutorial" in the
Keywords field.


Important dates:
 -    30 Jan 2017 Submission deadline
 -    27 Feb 2017 Notification of acceptance
 -    20 Mar 2017 Final papers due
 - 03-04 Apr 2017 Symposium

Programme chair:
  Alberto Riva, University of Florida, USA

Programme committee:
  Marco Antoniotti, Università Milano Bicocca, Italy
  Marc Battyani, FractalConcept
  Theo D'Hondt, Vrije Universiteit Brussel, Belgium
  Marc Feeley, Université de Montreal, Canada
  Stelian Ionescu, Google
  Rainer Joswig, Independent Consultant, Germany
  António Menezes Leitão, Technical University of Lisbon, Portugal
  Nick Levine, RavenPack
  Henry Lieberman, MIT, USA
  Mark Tarver, Shen Programming Group
  Jay McCarthy, University of Massachusetts Lowell, USA
  Christian Queinnec, Université Pierre et Marie Curie, France
  François-René Rideau, Bridgewater Associates, USA
  Nikodemus Siivola, ZenRobotics Ltd
  Alessio Stalla, Università degli Studi di Genova, Italy

Search Keywords:

#els2017, ELS 2017, ELS '17, European Lisp Symposium 2017,
European Lisp Symposium '17, 10th ELS, 10th European Lisp Symposium,
European Lisp Conference 2017, European Lisp Conference '17

Thursday, March 24 2016

ELS 2016 registration now open!

Some people do seem to be in the starting blocks for the 9th European Lisp Symposium. One person has already booked his flight, while 3 people from Poland registered yesterday, with the web form that I was still testing. All of this, without the final programme being available, and hell, we're still missing a couple of reviews!

Thank you for the confidence! The registration page is now officially open! :-)

Wednesday, November 4 2015

ELS 2016 second invited speaker announced!

We're happy to announce our second invited speaker for the next European Lisp Symposium (May 9-10 2016, Krakow, Poland). Francis Sergeraert (Institut Fournier, Grenoble, France) will be speaking about lexical closures and complexity. All the details are already on the website...

Declt 2.0.1 "Benjamin Sisko" is out

Declt 2.0.1 "Benjamin Sisko" is out. This is a bugfix release with one internal change (a special variable was not following the earmuffs convention) and one actual bugfix (the same Texinfo anchor was generated for symbols with the same name but in different packages).

Find it at the usual place...

Tuesday, October 20 2015

ELS 2016 first invited speaker announced!

We're happy to announce our first invited speaker for the next European Lisp Symposium (May 9-10 2016, Krakow, Poland). Pierre Castéran (University of Bordeaux, France) will be speaking about program proof and synthesis with Coq. All the details are already on the website...

Wednesday, October 14 2015

In Cooperation with: ACM SIGPLAN for ELS

We're happy to announce that the European Lisp Symposium is now "In Cooperation with: ACM SIGPLAN". The proceedings will be published in the ACM Digital Library.

Monday, October 12 2015

ASDF-FLV 2.0

I've just released version 2.0 of ASDF-FLV, my ASDF extension for supporting file-local variables (ala *PACKAGE*). The code hasn't changed, but as for my other libraries, the system and package names are now prefixed with net.didierverna. ASDF-FLV is also available on GitHub now.

The reason I'm doing this now is that at least two of my other libraries are going to use it in a mandatory way, either directly or indirectly (and in turn, that's because no implementation has bothered to implement CDR #9 yet ;-).

Wednesday, October 7 2015

ELS 2016 Call for Papers

		 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, 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

Monday, October 5 2015

ELS 2016 coming in hot!

We're happy to announce that the next European Lisp Symposium will be held at the AGH University of Science and Technology in Kraków, Poland, on May 9-10. Stay tuned for updates, upcoming CfP, invited speakers and lots of good stuff!

Wednesday, August 5 2015

The Return of Segfaults

I was watching the discussion between Gilad Bracha and Matthias Felleisen on gradual typing this afternoon (it's available on YouTube). This was the last event at the STOP workshop, part of ECOOP 2015 in Prague. I couldn't attend it because I was somewhere else (Curry On) at the time. The discussion is interesting, but if you go all the way, in the last 10 minutes or so, you will notice that Matthias seems to be completely obsessed with what he calls the "Return of the SegFaults".

Basically, the point is the following. Mathias dislikes the optional types in Common Lisp because it's opening the door to unsafety. Initially, any dynamic language has a sound type system (all type errors are caught; at run-time, yes, but they are caught). As soon as you introduce an optional type system ala Lisp, the compiler implementors are "pushed" to use the provided type information for optimization, hence weakening the type system and breaking soundness. It's the "return of segfauts".

Of course, I agree with that, at least on the principle. Yes, Common Lisp's weak, optional type system is an antiquated thing. However, it seems to me that Matthias is forgetting two important things on the practical level:

  1. by default in many implementations that I know, if not all of them, introducing type declarations doesn't actually break the soundness of the type system but leads to even more type checking. For example, (defun plus (a b) (+ a b)) works on every possible numerical value, but add (declare (type fixnum a b)) in there and it will suddenly stop working on anything else but integers. It's only if you require the compiler to optimize for speed at the expense of safety that you effectively weaken your type system.
  2. In practice, the risk of re-introducing segfaults in your application may be mitigated by the interactive aspect of the development (TDD made easier, simultaneous write / compile / run / test / debug phases etc.).

So my impression is that Matthias is largely exaggerating the problem, but I'm not really qualified to tell. That's why I would like to know from you guys, working with Lisp in the industry, writing large applications, lots of type annotations, and (declaim (optimize (speed 3) (safety 0) (debug 0)) (EDIT: that's exaggerated of course, I really mean breaking safety for performance reasons): how much of a problem the "return of the segfaults" really is in practice ?

As a side note, this reminds me of the dynamic vs. lexical scoping debate. Many people were and still are strongly opinionated against dynamic scoping by default. Of course, I too, at least in principle. But how dangerous dynamic scoping really is in practice (EDIT: I'm not talking about expressiveness, e.g. closures, here. Only unsafety.)? What I can tell you is that in the 15 years I was actively maintaining the XEmacs codebase, I may have run into name clashes due to dynamic scoping... twice.

Monday, July 13 2015

Declt 2.0 is out -- IMPORTANT

Declt 2.0 "Kathryn Janeway" is out. This release doesn't contain any change in functionality, yet deserves a major version upgrade since it contains 3 important changes: an infrastructure revamp (along the lines of what Clon endured not so long ago), a license switch from the GNU GPL to a BSD one, and finally a system / package name change. The prefix is now net.didierverna instead of com.dvlsoft. Do I need to apologize for this again? :-)

Find it at the usual place...

Monday, June 29 2015

Declt 1.1 is released

Hello,

as promised last week, I've just released a new version of Declt, my reference manual generator for ASDF systems. This new version (1.1) is now able to document Clon again (the documentation of which has been updated on the website).

New in this release:

  • Declt now properly handles and documents complex system and component dependencies, such as :feature :require and :version statements,
  • Declt also documents a system's :if-feature if any.

But the most important addition is the ability to document several ASDF systems in the same reference manual. More precisely, Declt now documents not only the main system but also all its subsystems. A subsystem is defined as a system on which the main one depends on in any way, and which is also part of the same distribution (under the same directory tree). Declt also understands multiple system definitions from the same .asd file.

Enjoy!

Thursday, June 25 2015

Clon 1.0b24 is released -- IMPORTANT

Hello,

I'm happy to announce the release of the next beta version of Clon, the Common Lisp / Command Line Options Nuker library. This release doesn't contain much change in terms of functionality, but it contains a lot of change in terms of infrastructure, plus very important and backward-incompatible modifications. So if you're a Clon user, please read on.

First of all, a huge revamp of the library's infrastructure (package hierarchy, ASDF and Make implementations) occurred. A large portion of this work is actually not mine, but Fare's (big thanks to him, 'cause the level of ASDF expertise required just means that I couldn't have done that by myself). The purpose here was twofold: first, remove all logic from the ASDF files (so that other system managers could be used; not sure that's actually useful right now) and second, split the library in two: the core, basic functionality and the non-standard platform-dependent bells and whistles (read: termio support). The result is that Clon now comes with 4 different ASDF systems! A setup system allows you to configure some stuff prior to loading the library, a core system allows you to load only the basic functionality and the regular one loads everything, autodetecting platform-dependent features as before. The fourth system is auxiliary and not to be used by hand. All of this is properly documented. For a code maniac like me, this new infrastructure is much more satisfactory, and I've learned a lot about ASDF less known features.

Next, I've moved the repository to Github. Please update your links! It seems that I've lost all my former tags in the process, but oh well...Only the Git repo has moved. The main Clon web page still contains the full history of tarballs, the preformatted documentation, and will continue to do so in the future.

Finally (I've kept this to myself until the last possible minute because I'm scared like hell to tell): I've changed the systems and packages names... The com.dvlsoft prefix has been replaced with net.didierverna. All other libraries of mine will eventually endure the same surgery. It's for the best, I apologize for it and I swear I will never ever do that again, EVER (fingers crossed behind my back).

So what's next? Before considering an official 1.0 release, there are two things that I want to do. First, cleanup some remaining Fixmes and some shaky error handling. Second, provide an even simpler way of using Clon than what the Quick Start chapter in the doc demonstrates. The idea is to just implement a main function with keyword arguments, and those argument magically become command-line options.

A side-effect of this work is that Declt now chokes on Clon, because some ASDF features that it doesn't understand are in use. So Declt has a couple of new challenges ahead, and you should expect a new release in the weeks to come.

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