Gambit-list Avril 2009

gambit-list@iro.umontreal.ca

27 participants
38 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

2 2

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/

5 7

Re: [gambit-list] Speed improvement of lib/digest.scm
by Marc Feeley 18 Nov '09

18 Nov '09

On 19-Feb-09, at 4:49 PM, Mikael More wrote: > Cool! > > Useful! > > What is the approx speed on your machine btw? > On my 2GHz Mac Book Pro: For MD5: 0.06 seconds per MB. For SHA-1: 0.13 seconds per MB. That's still about 3 times slower than the "md5" utility on my machine, but still not too bad for bit-bashing code entirely written in Scheme. Marc

4 10

scheme on llvm
by lowly coder 31 Jul '09

31 Jul '09

this is kinda off topic, -- but people here seem really smart, so I'll risk the occasional flames for good criticism + insight i think the llvm/jvm projects are really cool, since so much work is put into jitting; and for one reason or another, I like llvm more than jvm i'm curious about the possiblity of a high performance scheme (and perhaps gambit in particular) running on llvm; where the 'initial implementation' may not be all that fast ... but letting llvm jit it away how does this sound? feasible for a scheme (but not gambit)? down the pipes planned for gambit? or totally stupid/crazy? the 'main' advantage of this approach is that I _assume_ that the llvm guys are pretty good at hacking up interpreters / jit's ... so why not benefit from their constant progress :-D

5 7

I/O puzzle...
by Marc Feeley 09 Jui '09

09 Jui '09

Puzzle... what's the bug in the following code? See end of message for answer. (define http-server-start! (lambda (hs stop?) (let ((server-port (open-tcp-server (list port-number: (server-port-number hs) backlog: 128 reuse-address: #t server-address: '#u8(127 0 0 1) ; on localhost interface only char-encoding: 'ISO-8859-1)))) (input-port-timeout-set! server-port 3) (accept-connections hs server-port stop?)))) (define accept-connections (lambda (hs server-port stop?) (let loop () (let ((connection (read server-port))) (if (eof-object? connection) (if (stop?) (close-input-port server-port) (loop)) (begin (if (server-threaded? hs) (let ((dummy-port (open-dummy))) (parameterize ((current-input-port dummy-port) (current-output-port dummy-port)) (thread-start! (make-thread (lambda () (serve-connection hs connection)))))) (serve-connection hs connection)) (loop))))))) . . . . . . . . Answer: the (input-port-timeout-set! server-port 3) is at the wrong place. It sets a timeout ***3 seconds in the future***. So after 3 seconds have passed all calls to read in accept-connections will not block (and lead to a tight, CPU intensive loop). The correct approach is to put the call to (input-port-timeout-set! server-port 3) just before the call to read. Puzzle #2: why did Gambit chose to define timeouts that are not relative to the moment that an I/O function is called? Marc

2 3

Reading S-expressions
by Briggs, Jamie 01 Mai '09

01 Mai '09

I've been dabbling with scheme off and on for a while but I am just getting started with Gambit-C. I am trying to read the output of a program printing information in the form of s-expressions. The problem is that it puts single quotes around strings. eg. (domain (domid 1) (on_crash restart) (image (linux (kernel /boot/vmlinuz-2.6.18-5-xen-amd64) (ramdisk /boot/initrd.img-2.6.18-5-xen-amd64) (args 'root=/dev/sda1 ro ') ... and so on I have an mzscheme script that reads it by messing with the readtable; the code looks like: ; (mzscheme code) ; Read after redefining so that single quotes are handled like pipe quotes (define (read-data inport) (parameterize ((current-readtable (make-readtable #f #\' #\| #f))) (let ((domain (read inport))) (if (eof-object? domain) '() (cons domain (read-data inport)))))) The readtable stuff in gambit is different, obviously, so how would I go about tackling this problem? I've done some reading and trying different things but my scheme chops are weak and at this point I'm stumped. Thanks for your help. - Jamie =============================== CONFIDENTIAL & PRIVILEGED COMMUNICATION The information contained in this message is privileged, confidential, and protected from disclosure. This message is intended for the individual or entity addressed herein. If you are not the intended recipient,please do not read, copy, use or disclose this communication to others. Also please notify the sender by replying to this message, and then delete it from your system. The sender totally disclaims, and will not accept, any responsibility or liability for the unauthorized use, or the consequences of any unauthorized use, of this communication or message.

4 3

trade imbtalance
by Frank Gizinski 30 Avr '09

30 Avr '09

To whom it may concern, I just joined this mailing list recently because I didn't think I had much to say. I don't know anything about UNIX. The tube on the 333Mhz Mac that I had for nine months burned out so now I have a H-P running Windows Vista. The Gambit version I had on my Mac was 3.0. I downloaded the latest of this version on the new machine and found out that when you type a ( or ) you get angle brackets. So I downloaded 4.0.0 and a few later versions and found out in every case you get warnings from Microsoft that they never heard of these people, they don't have the right kind of code and they won't install it. I assume some other people had have this problem. Why can't some of your people tell your ambassador to the United States tell our people that this is against NAFTA. Does anyone know anyway of getting Microsoft's 'security' shield off the Gambit icon I've got? Frank Gizinski

3 2

Yes, the module system is published. Re: Subdivide code
by Mikael More 30 Avr '09

30 Avr '09

The addressed module system is Black Hole, that you have a brief introduction and download URL to on http://mwaza.dyndns.org/apps/files/bh-tutorial.html <http://mwaza.dyndns.org/apps/files/bh-tutorial.html> . Email me any feedback and questions you have on the introduction. More documentation is underway, and will be published in approx a month. The module system does macro export automatically, and dependency loading and compilation. The documentation will describe this clearly. Mikael 2009/4/30 Valeriya Pudova <val1969(a)neotech.lv> > Hello good people, > > | --- "A Tour of Scheme in Gambit.pdf" > | In Gambit, a good way to subdivide code is by using the X module system. > | The layout is pretty straight-forward: > | create a .scm-file . Start it with (module name) where name is the name. > | Then, declare what other modules to use with the (use) procedure. > For instance: > | (use lib/srfi1 lib/http-client) > > Is it true? > > I see, the Gambit has two methods: 'include' and 'load' > First method 'include' lets subdivide app into files. It can be helpful > but it is pure method (similar to include of C language). > Programmer should avoid recursively included files, etc. > For me 'include' is not good way how to code app. > > The method 'load' lets subdivide app into the modules. This should > be better that 'include' (for me). But it has limitation. The macro > definition usable only at one file. > > |--- manual: > | To have access to the macro definitions contained in > | a file, that file must be included using the include special form. > > Maybe that is why the statistic of using 'include' is higher that for > 'load' method. Also i seen at the source files list of the > "Space Invaders classical arcade game" that programmer split > modules into 2 files one is for code and second for macros, and last > one must be included when first can be loaded. > > Does not look like pretty. Fix me if I am wrong please. > > What is correct template how to subdivide app into modules? > Maybe there is lightweight module system library exists? > _______________________________________________ > Gambit-list mailing list > Gambit-list(a)iro.umontreal.ca > https://webmail.iro.umontreal.ca/mailman/listinfo/gambit-list >

1 0

Subdivide code into modules
by Valeriya Pudova 30 Avr '09

30 Avr '09

Hello good people, | --- "A Tour of Scheme in Gambit.pdf" | In Gambit, a good way to subdivide code is by using the X module system. | The layout is pretty straight-forward: | create a .scm-file . Start it with (module name) where name is the name. | Then, declare what other modules to use with the (use) procedure. For instance: | (use lib/srfi1 lib/http-client) Is it true? I see, the Gambit has two methods: 'include' and 'load' First method 'include' lets subdivide app into files. It can be helpful but it is pure method (similar to include of C language). Programmer should avoid recursively included files, etc. For me 'include' is not good way how to code app. The method 'load' lets subdivide app into the modules. This should be better that 'include' (for me). But it has limitation. The macro definition usable only at one file. |--- manual: | To have access to the macro definitions contained in | a file, that file must be included using the include special form. Maybe that is why the statistic of using 'include' is higher that for 'load' method. Also i seen at the source files list of the "Space Invaders classical arcade game" that programmer split modules into 2 files one is for code and second for macros, and last one must be included when first can be loaded. Does not look like pretty. Fix me if I am wrong please. What is correct template how to subdivide app into modules? Maybe there is lightweight module system library exists?

1 0

Re: [gambit-list] SRFI-13
by Arthur Smyles 29 Avr '09

29 Avr '09

Yes, I have a copy of it here: http://smyles.com/projects/r6gambit/darcs/libs/rnrs/unicode/ It should be relatively straight forward if you want to convert it to r5rs. You will need to change the names for the (rnrs bytevector) procedures into the gambit ones. I have a mapping here: http://smyles.com/projects/r6gambit/darcs/libs/rnrs/bytevectors.scm The only changes I made to these libraries was to make the reader syntax compatible with gambit's syntax for u8-vectors and updated the library import headers since they didn't work with the modern r6rs spec. The r6rs reference implementation has additional documentation on how these libraries are organized. http://www.r6rs.org/refimpl/r6rs-unicode-library.tar.gz Arthur On 15-Apr-09, at 10:53 AM, Alex Queiroz wrote: > Hallo, > > On 4/15/09, Bradley Lucier <lucier(a)math.purdue.edu> wrote: >> >> At one point my implementations of SRFI 13 and 14 used the internal >> Gambit API to properly check the types and bounds of arguments and >> raise >> exceptions with the proper continuations. That API has changed >> since I >> wrote those, but there are only a few macros and types that have to >> be >> rewritten to bring it up to date, but I don't have time to do so now. >> > > It built flawlessly with 4.4.2, but then it may give unpleasant > surprises at runtime. I'll try to spot the needed changes. > >> Also, I use a very naive bitmap implementation for character sets, >> which >> is OK for Latin-1 but not for Unicode, so a different data structure >> should be used for that. Haven't done that, either. >> > > Hmmm. this is more serious since I tend to use UTF-8 encoding. Are you talking about the Unicode character class tables? If I'm not mistaken Will Clinger wrote a fairly compact and fast implementation of those tables. The code must be in Larceny somewhere. I believe it is also part of the reference implementation for R6RS. Marc

3 2

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

Gambit-list Avril 2009