Gambit-list Octobre 2010

gambit-list@iro.umontreal.ca

10 participants
9 discussions

Edge triggered I/O with libevent
by Adam Langley 04 Avr '13

04 Avr '13

Gambit uses the select call on POSIX systems to multiplex IO operations. This is fine for small numbers of file descriptors, but falls apart quickly with large numbers[1]. libevent[2] is a wrapper library around a number of modern IO multiplexing systems (epoll on Linux, kqueue on the BSDs as well as poll and select). Attached is a patch which converts Gambit to using edge triggered I/O with epoll and libevent. This also requires a patch (attached) of libevent since the standard distribution doesn't include edge triggering support and the upstream appears to be on holiday. (epoll is required because I don't have a BSD box on which to develop edge triggering support for kqueue) This patch (for Gambit) preprocesses away to nothing unless --enable-libevent is passed to the configure script. (Note that, since this patches the configure.ac script, you'll need to run autoconf to regenerate). I hope I've not broken anything, but at this stage I've only tested that the console and tcp ports work. This patch (in the future) should also allow people, who write programs which use socket calls directly, to integrate into the main event loop at some point. Testing is more than welcome and, if you find a form of IO which is broken, please email me. [1] http://monkey.org/~provos/libevent/libevent-benchmark2.jpg [2] http://monkey.org/~provos/libevent/ -- Adam Langley agl(a)imperialviolet.org http://www.imperialviolet.org (+44) (0)7906 332512 PGP: 9113 256A CC0F 71A6 4C84 5087 CDA5 52DF 2CB6 3D60

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How to pass a u8vector to the FFI
by Mikael 20 Sep '11

20 Sep '11

You do this, by declaring the passed u8vector as a scheme-object in the c-lambda definition. The memory pointer to the u8vector's contents in the C code is resolved by void *u8vectorptr = ___CAST(void*,&___FETCH_U8(___BODY(theu8vectorschemeobjectvariable),___INT(0))); Remember that the pointer is only to be kept until the next return to Scheme. Mikael 2010/3/30 Álvaro Castro-Castilla <alvaro.castro.castilla(a)gmail.com> > Hi! > > Is there a way to pass a u8-vector to a FFI interface somehow? > The way I expect this to work is through a (pointer unsigned-char), but it > obviously doesn't work, claiming a proper C pointer. I would like to be able > to build this arrays from Scheme code. Is there a way? > > Currently I have to call a FFI function to set char by char, calling the > c-lambda function too many times. > > One thing that could work is something that converts u8-vectors to unsigned > char* arrays, does that exist in Gambit? > > > Thanks, > > Álvaro > > _______________________________________________ > Gambit-list mailing list > Gambit-list(a)iro.umontreal.ca > https://webmail.iro.umontreal.ca/mailman/listinfo/gambit-list > >

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Gambit Scheme Inside Out talk at ILC2010
by Marc Feeley 16 Nov '10

16 Nov '10

Hello. I gave a talk on Gambit at ILC2010 yesterday. It presents highlights of both the Gambit Scheme language and its implementation. You can find it at: http://www.iro.umontreal.ca/~gambit/Gambit-inside-out.pdf The .pdf is 24MB so it might be a longish download... Many thanks to Guillaume Cartier, James Long and Robert Lizee for providing some nice demos. For the record, some participants said that now that they know Gambit they see less of a reason to use Common Lisp (whatever that means!). Marc

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Confused
by Bradley Lucier 24 Oct '10

24 Oct '10

Marc: Can you explain what's going on here? I would expect both expressions to print the same. Brad [Bradley-Luciers-MacBook-Pro:~] lucier% gsi cond-test.scm a #!void [Bradley-Luciers-MacBook-Pro:~] lucier% cat cond-test.scm (pretty-print (let ((else #f)) (cond (else 'a)))) (pretty-print (cond (#f 'a))) [Bradley-Luciers-MacBook-Pro:~] lucier% gsi -v v4.6.0 20100716125419 i386-apple-darwin10.4.0 "./configure CC=/pkgs/gcc-4.5.1/bin/gcc -fschedule-insns -march=native --enable-single-host --enable-multiple-versions --enable-shared"

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Continuations and C callbacks
by Jeremie Lasalle Ratelle 15 Oct '10

15 Oct '10

In the windows gui code of Jazzscheme we have to use callbacks from c to dispatch events to do event dispatching. This is a requirement of windows. The event loop : http://pastebin.com/iBT85Yev It calls DispatchMessage which ultimately calls our callback. The callback must either handle the message and return 0 or call DefWindowProc which is the default handler. The Jedi debugger allows the message loop to be restarted when an error occurs. For that, it uses continuations. Those continuations jump over the c code causing problems because the c frames are not cleared and the handler does not return. To fix that, I developped a new version of dynamic-wind that I call with-continuation-checkpoints. Instead of being thunks, the before and after functions take two arguments, the exit and the restart. The exit is simply the continuation of the with-continuation-checkpoints call which allows to stop the continuation invocation. The restart is a thunk that make the original continuation invokation call. It might be a continuation-return or a continuation-graft. This allows resuming the continuation invocation at a different point in the code. An example similar to the windows event loop : http://pastebin.com/xn2EaYYZ This example shows how we can use with-continuations-checkpoints to unwind the c-stack and correctly return from the handler. Any suggestions? Comments?

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gambit and racket
by Hendrik Boom 14 Oct '10

14 Oct '10

Just wondering -- is there any level of compatibility between Gambit and Racket (nee PLT Schene) beyond the fact that both implement Scheme? -- hendrik

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Porting to "small" machines -- target requirements?
by Michael Wirth 07 Oct '10

07 Oct '10

Folks, Has anyone done an estimate (or measurement!) of the resources required on the target platform to do a port of Gambit? For example, for a given processor architecture, what are the memory requirements to support a port of the interpreter for code, stack space, data RAM, etc. Other HW resources and functional support? I have in mind the types of processors currently used by "embedded systems", which tend to have lots of processor power, but either simple and small memories or rather baroque memory architectures (e.g., a mixture of ROM, fast and slow RAM, writeable FLASH, etc.) and no VM support or rotating storage. It would be nice to get some "lessons learned" feedback from Gambit porters before charging down a blind alley myself :-) Mike Wirth Palo Alto, CA

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Beginner problem with Gambit and Blackhole
by Karel Miklav 05 Oct '10

05 Oct '10

I'm fresh in this environment and here is my problem: tp> uname -mrs FreeBSD 7.3-STABLE i386 tp> bsc Loaded Black Hole. Gambit v4.6.0 > (import (std srfi/13)) > (string-upcase "Try this") "TRY THIS" > (string-trim-both " xy ") *** ERROR IN #<procedure #2>, "my/code/scheme/lib/blackhole/std/srfi/13.scm"@1184.1 -- Unbound variable: 13_#char-set? 1> When I try to blindly fix the offending call in 13.scm to 14_#char-set I get other problems. Anybody knows what am I doing wrong? Maybe I pulled down the wrong version: git clone git://github.com/pereckerdal/blackhole.git bh/ git clone git://github.com/pereckerdal/blackhole-libs.git bh/std/ -- Thanks, Karel Miklav

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ILC 2010 Schedule
by Antonio Menezes Leitao 04 Oct '10

04 Oct '10

With the usual apologies to those who receive multiple copies. This version contains the schedules of presentations and tutorials. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ International Lisp Conference 2010 October 19-21, 2010 John Ascuaga's Nugget (Casino) Reno/Sparks, Nevada, USA (near Lake Tahoe) Collocated with SPLASH 2010 (OOPSLA & DLS & more) see also http://splashcon.org as well as http://www.dynamic-languages-symposium.org/dls-10/ In association with ACM SIGPLAN ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The Association of Lisp Users is pleased to announce the 2010 International Lisp Conference, to be held in Reno, Nevada, in collocation with SPLASH 2010. This year's program consists of tutorials for beginners and advanced users, a selection of prominent invited speakers, an excellent technical session, lightning talks and an open forum. All ILC and other SPLASH co-located registrants have free admittance to the ILC tutorials. Note that these tutorials are double-tracked across from the early-morning SPLASH keynote addresses. Schedule: ~~~~~~~~~ See also http://www.international-lisp-conference.org/2010/schedule Tuesday, October 19 ~~~~~~~~~~~~~~~~~~~ ILC tutorial: Ernst van Waning Introduction to Common Lisp, part 1 SPLASH keynote: Stephanie Forrest The Case for Evolvable Software ILC invited speaker: Dr. Lawrence Hunter Building a Mind for Life ILC invited speaker: Jans Aasman AllegroGraph and the Linked Open Data Cloud Hannes Mehnert Extending Dylan's Type System for Better Type Inference and Error Detection Shingo Yuasa and Masahiro Yasugi Validating Low-Level Instructions for Fixnums using BDDs Roy Turner LP/Lisp: Literate Programming for Lisp Francois-Rene Rideau and Robert Goldman ASDF 2: Evolving an API to Improve Social Interactions Wednesday, October 20 ~~~~~~~~~~~~~~~~~~~~~ ILC tutorial: Ernst van Waning Introduction to Common Lisp, part 2 ILC tutorial: David Margolies AllegroGraph, Lisp for a NoSQL World SPLASH keynote: Benjamin C. Pierce Art, Science, and Fear ILC invited speaker: Marc Feeley Gambit Scheme: Inside Out ILC invited speaker: Peter Seibel Common Lisp Standardization: The Good, the Bad, and the Ugly Tomoharu Ugawa, Hideya Iwasaki, and Taiichi Yuasa Starvation-free Heap Size for Replication-Based Incremental Compacting Garbage Collection John Maraist NST: A unit testing system for Common Lisp ALU meeting Thursday, October 21 ~~~~~~~~~~~~~~~~~~~~ ILC tutorial: Introduction to Common Lisp, part 3 SPLASH keynote: Kenneth Stanley Searching Without Objectives ILC Invited speaker: Lowell Hawkinson Lisp for Breakthrough Products ILC Invited speaker and SPLASH keynote: Don Syme F#: Taking Succinct, Efficient, Typed Functional Programming into the Mainstream Didier Verna CLon, the Command-Line Option Nuker Masahiro Yasugi, Tsuneyasu Komiya, Tasuku Hiraishi and Seiji Umatani Managing Continuations for Proper Tail Recursion Lightning talks and open forum Conference Registration: ~~~~~~~~~~~~~~~~~~~~~~~~ Due to colocation, registration must be done using ILC/SPLASH'10 unified registration forms available at http://splashcon.org Please note that the registration page (page 3) has the option "SPLASH (OOPSLA/Onward!)" selected by default. If you are only planning to attend ILC, don't forget to deselect that option. Travel and Accommodation: ~~~~~~~~~~~~~~~~~~~~~~~~~ SouthWest Airlines offers low fares into Reno but requires booking online at www.southwest.com John Ascuaga's Nugget offers reduced rates for ILC participants; see http://splashcon.org to obtain the group code; or you can have your travel agent look for best bookings (e.g. priceline.com) Scope: ~~~~~~ Lisp is one of the greatest ideas from computer science and a major influence for almost all programming languages and all sufficiently complex software applications. The International Lisp Conference is a forum for the discussion of Lisp and, in particular, the design, implementation and application of any of the Lisp dialects. We encourage everyone interested in Lisp to participate. Organizing Committee: ~~~~~~~~~~~~~~~~~~~~~ * General Chair: JonL White - The Ginger IceCream Factory of Palo Alto, ALU * Program Chair: Antonio Leitao - Instituto Superior Tecnico/INESC-ID * Conference Treasurer: Duane Rettig - Franz, Inc., ALU Director * Publicity Chair: Daniel Herring - ALU Director * ALU Treasurer: Rusty Johnson - TASC, Inc., ALU Director Program Committee: ~~~~~~~~~~~~~~~~~~ * Antonio Leitao - Instituto Superior Tecnico/INESC-ID, Portugal * Alex Fukunaga - University of Tokyo, Japan * Charlotte Herzeel - Vrije Universiteit Brussel, Belgium * Christophe Rhodes - Goldsmiths College, University of London, UK * Didier Verna - EPITA Research and Development Laboratory, France * Duane Rettig - Franz, Inc., USA * Giuseppe Attardi - University of Pisa, Italy * Jeff Shrager - Symbolic Systems Program, Stanford University, USA * Joe Marshall - Google, Inc., USA * Julian Padget - University of Bath, UK * Keith Corbett - Clozure Associates, USA * Kent Pitman - PTC, USA * Manuel Serrano - INRIA Sophia Antipolis, France * Marc Feeley - University of Montreal, Canada * Marie Beurton-Aimar University of Bordeaux 1, France * Mark Stickel - SRI International, USA * Matthias Felleisen - Northeastern University, USA * Scott McKay - ITA Software, USA Contacts: ~~~~~~~~~ * Questions: ilc10-organizing-committee at alu.org * Program Chair: ilc2010 at easychair.org For more information, see http://www.international-lisp-conference.org

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Gambit-list Octobre 2010