December 2009 - 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

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Re: [gambit-list] What is required to port gambit to a new cpu?
by Marc Feeley 27 Jan '10

27 Jan '10

I've seen exactly this behaviour when the include/gambit.h.in file determines the wrong endianness for the CPU. Given that the ARM can either be little or big-endian, chances are good that the #ifdefs in the gambit.h.in file are not sufficient to detect the endianness on the Nokia platform. Usually the C compiler or development environment will define a symbol that indicates the endianness of the CPU, and the gambit.h.in file needs to be modified to test this symbol. Here is an excerpt of the gambit.h.in file which determines the endianness when the CPU is an ARM: #ifndef ___BIG_ENDIAN #ifndef ___LITTLE_ENDIAN ... #ifdef ___CPU_arm #ifdef _LITTLE_ENDIAN #define ___LITTLE_ENDIAN #endif #ifdef __LITTLE_ENDIAN__ #define ___LITTLE_ENDIAN #endif #ifdef __LITTLE_ENDIAN_DATA__ #define ___LITTLE_ENDIAN #endif #endif ... #endif #endif Note that by default the gambit.h.in file assumes the endianness is big-endian. So I'm pretty sure none of the symbols _LITTLE_ENDIAN, __LITTLE_ENDIAN__, and __LITTLE_ENDIAN_DATA__ are defined and the gambit.h.in file will assume incorrectly that the endianness is big-endian. There are two solutions. #1, the clean way, is to check the compiler documentation to see which symbol is defined by the C preprocessor to indicate the endianness, and to modify the above sequence of #ifdefs to take that into account. #2, the brute force way, is to add #define ___LITTLE_ENDIAN at the top of the gambit.h.in file. I propose you try #2 first, and if that solves the problem, then try #1 and send me a patch so I can modify my source code. Note that after modifying the include/gambit.h.in file, you will have to do a ./configure and probably a "make mostlyclean" before "make". Marc On 2009-12-29, at 3:49 AM, Frederick LeMaster wrote: > Thanks! > > I tried it out and some things work great, such as cons and most of > the list functions, but the reader seems to be having some serious > issues: > >> 0 > 3 >> 1 > 2 >> 2 > 1 >> 3 > 0 >> 4 > 7 >> 5 > 6 >> 6 > 5 >> 7 > 4 >> 8 > *** ERROR IN (console)(a)9.1 -- Unbound variable: 8 > 1> > > It seems like it is failing to read the digits properly as numbers. > The arithmetic routines seem okay though, >> (number->string (+ (string-length "elephant") (string-length ""))) > "8" > > Is the reader making an unsafe assumption? > -Fred LeMaster > > On Mon, Dec 28, 2009 at 6:40 AM, Marc Feeley <feeley(a)iro.umontreal.ca> wrote: >> >> On 2009-12-28, at 3:04 AM, Frederick LeMaster wrote: >> >>> Hello Dr. Feeley, >>> I am interested in using gambit on the nokia n900 tablet, which >>> features an ARMv7 cpu. What changes would I need to make in the gambit >>> sources to allow it to function correctly on this architecture? >> >> Nothing! It should work "out of the box". >> >> Marc

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Interactive 3D graphics with Gambit-C
by Alex Sandro Queiroz e Silva 06 Jan '10

06 Jan '10

Hallo, I am thinking about doing some basic 3D graphics with Gambit-C. Although I am sure code generated by Gambit-C is fast enough[1], I am a bit worried about the garbage collector. What's the type of garbage collector used by Gambit? If it kicks in during interactive rendering, should I expect annoying pauses? [1] - http://www.ventonegro.org/2008/09/the-need-for-speed/ -alex http://www.ventonegro.org/

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Gambit compiling from Source
by Nikhil Barthwal 20 Dec '09

20 Dec '09

Hi, I am new to Gambit as well as new to Scheme programming. I would like to download and use a Stable version of scheme. Also, I want to compile from source rather than use the binary distribution. Can someone tell me which file I need to download? I see bunch of files in the site. Which version is the stable version? And further whats the difference between gambc-v#_#_#-devel.tgz & gambc-v#_#_#.tgz and which one should I download? Thanks, Nikhil

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(currentthread)
by joe tex 17 Dec '09

17 Dec '09

I was trying to test examples in the Gambit-c manual. I am getting the following error message >gsi Gambit v4.5.3 > (currentthread) *** ERROR IN (console)(a)1.2 -- Unbound variable: currentthread Do I have to 'load' something before I call 'currentthread'? This is Gambit v4.5.3 compiled for Solaris 10. -- - Joe

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unquote-splicing silently drops non-list data
by Christian Jaeger 16 Dec '09

16 Dec '09

Gambit's unquote-splicing ignores the end of improper lists (when splicing into the middle of a list): > `(hello ,@"hmm" well) (hello well) > `(hello (unquote-splicing '("hmm" . "and")) well) (hello "hmm" well) Scheme-48 and Chicken throw an error in this case. Is there a reason an error should not be thrown? Christian.

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Some questions about reader in Gambit
by vasil 13 Dec '09

13 Dec '09

Hi, Marc! During last three days I am porting Qi (http://en.wikipedia.org/wiki/Qi_%28programming_language%29) to Gambit. qiYACC, qiReader, qiEval, qiCore are already ported, next will be qiProlog and Qi type checking machinery. And it will be cool if I integrate Qi reader with Gambits one. And there are some questions: 1. Could you please in two words explain source-location data? 2. Do interpreter and compiler use same method of file reading? Same readtable? 3. Qi constructions after Qi-reader are just like scheme ones, but before they are often different. For instance: Qi: [ A B | C ] after qi-reader: (cons A (cons B (cons C ()))) How can I integrate Qi reader into Gambit to slightly transform input with minimal effort? Vasil

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Looking for volunteers for Scheme language working groups 1 and 2
by Marc Feeley 08 Dec '09

08 Dec '09

[Apologies if you receive duplicates of this message.] The Scheme Language Steering Committee solicits volunteers who are willing to serve on working groups 1 and/or 2. Volunteers should: * be prepared to serve for the duration named in the group's charter charter for working group 1: http://www.scheme-reports.org/2009/working-group-1-charter.html charter for working group 2: http://www.scheme-reports.org/2009/working-group-2-charter.html * believe in the value of standardization * accept the goals and limitations of the working group's charter * support the goal of sharing Scheme code effectively * be able to work constructively toward compromise To volunteer for one or both of the working groups, send email to steering-committee-feedback(a)scheme-reports.org with the following information: your name your email address the working group(s) for which you are volunteering a statement explaining who you are and why and how you believe you would contribute to the success of the working group Please send your email by 8 January 2010. Will Clinger Marc Feeley Chris Hanson Jonathan Rees Olin Shivers

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Emacs + Gambit on Windows
by Siddharth 05 Dec '09

05 Dec '09

Hi, I'm trying out gambit 4.5.3 on Windows XP. I installed it using the mingw distribution. I can run both gsc and gsi just fine from a command console, but I can't seem to get inferior scheme mode working on Emacs (v23.1.1). I put gambit.el in my load path and set (require 'gambit) in my .emacs file. When I try to run gsi using Meta-x run-scheme, I get a new emacs buffer but don't seen the REPL. If I try to run gsi from a dos shell within emacs, a new windows pops up with gsi running, but it doesn't echo anything that I type. Any ideas? -- Siddharth

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Re: [gambit-list] Running make install for Gambit v4.5.3 in
by joe tex 02 Dec '09

02 Dec '09

Mark, For lib/makefile, I end up replacing $(INSTFILES_LIB_DATA) with $$INSTFILES_LIB_DATA. I also stripped out the backslash symbol from both the HEADERS_SCM and the LIBRARIES_SCM variables from the same file to allow the make install work for Solaris 10. Thanks for the support. - Joe On Tue, Dec 1, 2009 at 11:48 AM, Marc Feeley <feeley(a)iro.umontreal.ca>wrote: > > On 2009-12-01, at 11:40 AM, joe tex wrote: > > > Alex, > > > > I put ginstall in my current working directory and it doesn't seems to > make any change in the results. > > > > Mark, > > > > I replaced references to \# with # in lib\makefile and ran make install > and got this error message: > > > > for file in libgambc.a; do \ > > ../install-sh -c -m 644 $file $t_libdir/$file; \ > > done; \ > > if test "$t_libdir" != "$i_libdir"; then \ > > r_libdir=`../relpath "$t_libdir" "$i_libdir" no`; \ > > for file in _gambc.c "_kernel "_gambit libgambc.a; do \ > > (cd $i_libdir && ln -s $r_libdir$file $file); \ > > done; \ > > fi > > Try replacing the line > > (cd $i_libdir && ln -s $r_libdir$file $file); \ > > with > > (cd "$i_libdir" && ln -s "$r_libdir$file" "$file"); \ > > Marc > > -- - Joe

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