February 2010 - Gambit-list - mailman.iro.umontreal.ca

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

04 Apr '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

2 2

Blackhole and undefined variables.
by Tomi Neste 19 Mar '10

19 Mar '10

It seems that Blackhole doesn't give any warnings when importing modules with undefined identifiers. With vanilla Gambit when loading files with undefined variables I get the '*** WARNING -- Variable "bar" used in module "foo.o1" is undefined' message but with Blackhole's import there is not any indication of error until runtime. Could Blackhole be modified to give a warning (or even an error?) when this happens. If I have understood correctly, situation where an identifier is not defined in the current or any of the imported modules is always on error anyway (except for the identifiers defined in the Gambits standard library...)? It would be an nice feature to have since tracking the undefined variables (especially in compiled code which only gives the rather obscure runtime error 'Operator is not a PROCEDURE (#!unbound ...)' message) can be quite annoying some times. PS. What is the policy on Blackhole related discussion? I see that there is also an (very quiet) mailing list for it, should that be used instead? -- tomppa

3 2

[ANN] Call for Papers for 2010 Workshop on Scheme and Functional Programming
by Marc Feeley 23 Feb '10

23 Feb '10

Call for Papers 2010 Workshop on Scheme and Functional Programming Montréal, Québec, Canada Saturday and Sunday August 21-22, 2010 http://www.iro.umontreal.ca/~sfp2010 Important Dates --------------- Submission: 11 June 2010 Notification: 2 July 2010 Final papers due: 23 July 2010 All deadlines are at 14:00 UTC. Scope ----- The 2010 Workshop on Scheme and Functional Programming is a forum for discussing experience with and future development of the Scheme programming language. Papers are invited concerning all aspects of the design, implementation, theory, and application of Scheme. Some example areas include (but are not limited to): - History, evolution and standardization of Scheme - Applications, experience and industrial uses of Scheme - Program-development environments, debugging, testing - Implementation (interpreters, compilers, tools, benchmarks, etc) - Distributed computing, concurrency, parallelism - Interoperability with other languages, FFIs - Continuations, macros, modules, object systems, types - Theory, formal semantics, correctness - Education - Scheme pearls (elegant, instructive uses of Scheme) There are two classes of submissions, regular papers (up to 12 pages) and short papers (around 6 pages). A Scheme pearl submission is a special category, and should be a short paper presenting an algorithm, idea or programming device using Scheme in a way that is particularly elegant. Following the model of earlier workshops, Scheme pearls and experience papers need not necessarily report original research results; they may instead report practical experience that will be useful to others, re-usable programming idioms, or elegant new ways of approaching a problem. The key criterion for such a paper is that it makes a contribution from which other practitioners can benefit. It is not enough simply to describe a program! The proceedings of the conference will be published as a Université de Montréal technical report. Instructions for authors ------------------------ Authors should submit a 100-200 word abstract and a full paper by the end of Friday, 11 June Universal Coordinated Time. (The end of the day UTC corresponds to 8:00 PM EDT, 6:00 PM MDT, and 5:00 PM PDT.) Papers must be submitted in PDF format, or as PostScript documents that are interpretable by Ghostscript, and they must be printable on US Letter sized paper. Suitable style files for LaTeX: - class file http://www.iro.umontreal.ca/~sfp2010/sigplanconf.cls - style guide http://www.iro.umontreal.ca/~sfp2010/sigplanconf-guide.pdf - template http://www.iro.umontreal.ca/~sfp2010/sigplanconf-template.tex - sample paper http://www.iro.umontreal.ca/~sfp2010/retrospective.tex - sample references http://www.iro.umontreal.ca/~sfp2010/retrospective.bbl Submissions will be carried out electronically via the Web, at http://www.iro.umontreal.ca/~sfp2010/submit.html A submission will be evaluated according to its relevance, correctness, significance, originality, and clarity. It should explain its contributions in both general and technical terms, clearly identifying what has been accomplished, explaining why it is significant, and comparing it with previous work. The technical content should be accessible to a broad audience. There are two classes of submissions, regular papers and short papers: Regular papers -------------- Submissions should be no more than 12 pages (including bibliography and appendices) in standard ACM conference format: two columns, nine point font on ten point baseline, page 20pc (3.33in) wide and 54pc (9in) tall with a column gutter of 2pc (0.33in). Authors wishing to supply additional material to the reviewers beyond the 12 page limit can do so in clearly marked appendices, on the understanding that reviewers may not read the appendices. Submissions that do not meet these guidelines will not be considered. Short papers ------------ Short papers need not present novel research; it is sufficient that they present material of interest or utility to the Scheme or functional-programming community. Scheme pearls submissions should be presented as short papers. Short papers should be formatted with the same guidelines as regular papers, but are expected to be around six pages in length. Organization ------------ Conference Chair and Program Chair - Marc Feeley, Université de Montréal Program Committee - Alan Bawden, independent consultant - Olivier Danvy, Aarhus University - Christopher Dutchyn, University of Saskatchewan - Felix S. Klock II, Northeastern University - Jay McCarthy, Brigham Young University - Scott McKay, ITA software Steering Committee - William D. Clinger, Northeastern University - Marc Feeley, Université de Montréal - Robby Findler, University of Chicago - Dan Friedman, Indiana University - Christian Queinnec, University Paris 6 - Manuel Serrano, INRIA Sophia Antipolis - Olin Shivers, Northeastern University - Mitchell Wand, Northeastern University

1 0

Profiling compiled Gambit Scheme code
by James Long 18 Feb '10

18 Feb '10

Hey guys, I'm working on profiling some compiled Gambit Scheme code. I just wrote a quick article on some of my first attempts: http://jlongster.com/blog/2010/02/17/profiling-gambit/ My question is: what are some best practices? So far, I've compiled my code with "-track-scheme" and "-debug-location". Neither of those help real profilers, but it should help statprof. First, I tried using real profilers like Shark and Instruments. It worked out pretty good, but is there anything I can do to tell Gambit to compile my code in an orderly way and to do as little rearranging? Second, I tried statprof. It's great. I was able to get some decent output in my compiled program. I pumped up the thread heartbeat to 1/1000 instead of 1/100. However, strangely enough, when I tried running it straight on my iPhone, I got only ONE entry, the high-level function which runs everything, and of course it said 100%. I know statprof uses Gambit's internal function for tracking location. How do they work? If I've compiled in "-debug-location" my compiled code, even on the iPhone, should be able to keep track of itself, shouldn't it? (For those interested, I wrote a little server library which implements "remote files" so that statprof can connect to my computer from my iPhone and tell it to write all the HTML files.) Also, are there are declarations that will make a difference? My code is being compiled with "(block)", does that mean a lot of things will be collapsed together? - James

5 7

WAS Re: swank-gambit.scm question
by Grant Rettke 16 Feb '10

16 Feb '10

On Tue, Feb 16, 2010 at 6:16 AM, Julian Scheid <julians37(a)googlemail.com> wrote: > 2010/2/16 James Long <longster(a)gmail.com>: > Say in case you wanted to use SRFI-40 on the iPhone where > running Snow binaries is not an option, at least not a convenient one? Why isn't it an option to run Snow libs on Gambit-iPhone?

2 1

swank-gambit.scm question
by REPLeffect 16 Feb '10

16 Feb '10

James (and Marc), I've looked and I don't see anything about licensing on the Gambit Scheme backend. I believe James said he started with Marc's code and fleshed it out from there, so I'll direct the question to both of you. What are the license terms for using this code? Does it fall under the same licenses as Gambit itself? It's always good to know when you're using someone else's code.

6 13

swank-gambit backend for SLIME
by James Long 16 Feb '10

16 Feb '10

Hey guys, Marc and I have started work on adding support for Gambit to SLIME (http://common-lisp.net/project/slime/) We basically need to implement a fully functioning server (called a "swank" server) in Gambit to support all of the SLIME protocol. Marc wrote the initial draft and I have fleshed it out. Basic support for a SLIME repl and debugging is available. You can get the project here: http://github.com/jlongster/swank-gambit I think it'd be great if everyone worked on this together. There are many more commands that need to be implemented (completions, better debugging, etc.) and if we could get this fully implemented, it would be a huge benefit for Gambit. SLIME is really an incredible development environment and I think a lot more people would choose Gambit with SLIME support. To use it, fire it up in a terminal like so: $ gsi -:dar swank-gambit.scm The "-:dar" option just makes sure that you see any errors that happen in any threads. Now connect to it in Emacs: M-x slime-connect <ENT> <ENT> <ENT> And you should see a SLIME REPL if you activated the slime-repl library when you set it up. You should have done something like this when installing SLIME: (slime-setup 'slime-repl) SLDB is SLIME's debugger, and it will pop up if an error occurs, but many of the debugging commands haven't been implemented yet. You can embed the server wherever you like. I'm debugging my Gambit Scheme iPhone games using SLIME, which is neat. *** QUESTION FOR SLIME USERS *** I'm currently wrestling with what to do with program output from any thread. How do most SLIME backends handle it? I've sketched out an implementation which sends all output to the SLIME REPL. It's a little rough, but it seems to work. What would be the SLIME philosophy? Please let me know if you want to start hacking on this with us! - James

3 9

Compiling and Using Gambit for/on the iPhone update
by James Long 11 Feb '10

11 Feb '10

Hello everyone, I wrote an article about writing iPhone apps in Scheme about 8 months ago here: http://jlongster.com/blog/2009/06/17/write-apps-iphone-scheme/ If any of you all are using this, I wanted to update you. That information is getting a little old. I have created a page on my site which I will be continually updating with information on how to setup development for the iPhone with Gambit. You can find it here: http://jlongster.com/software/iphone/scheme-iphone-example/ The biggest change is that it's much easier to compile Gambit for the iPhone now. I have create a script called `configure-iphone` which wraps around "./configure" and sets up all the build options for the iPhone appropriately (link with right SDK, cross-compile possibly). More information about this script can be found here: http://jlongster.com/software/iphone/configure-iphone/ I will be posting more and more libraries which you will need if you are doing OpenGL programming on the iPhone. So far, here's what is available: Touch and accelerometer events: http://jlongster.com/blog/2009/07/20/touch-accelerometer-functionality-ipho… Remote debugging: http://jlongster.com/blog/2009/07/05/remotely-debugging-iphone-scheme/ Font rendering with FTGLES: http://jlongster.com/blog/2010/02/08/fonts-ugh/ FTGLES is my most recent work, and you can find Scheme bindings in the above article which I just posted. I will put up my .obj loader soon and any other libraries I have developed in Gambit. I'm not really trying to plug my website, but I really want other people to do developing OpenGL games in Gambit, and the iPhone is a good place to start! Let me know if you have any questions are opinions! Thanks! - James

5 5

Are optional arguments slow?
by Alex Queiroz 10 Feb '10

10 Feb '10

Hallo, I was wondering if the use of optional arguments conses or is otherwise slow and should be avoided in performace-critical code? Cheers, -- -alex @asandroq http://www.ventonegro.org/

2 1

Compiling Scheme programs on Windows with Gambit 4.6.0 and Visual C++ 2008 Express edition
by gidesa 07 Feb '10

07 Feb '10

Hello, I find useful to send this note to community. If you have installed Visual C++ 2008 Express edition, the script gambc-cc.bat needs a little modification to work: just in the top add these lines: rem ---------- Settings for Visual C++ Express 2008 --------- set COMPILER_DIRECTORY="C:\programs\Visual Studio 9.0\VC\bin" call %COMPILER_DIRECTORY%\vcvars32.bat rem ----------- end ------------------------------------------ Change the directory root "C:\programs" with your root, if you have installed Visual C++ in a different directory. Regards Giandomenico De Sanctis

1 0