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Web Framework for Gambit
by Rouan van Dalen 03 Nov '07

03 Nov '07

Hi. I am a newbie in scheme, but have been programming for about 7 years. I specialize in web application development and I am really interested in writing a web framework specifically for the Gambit scheme system. I was wondering what your thoughts are on this and if something like this already exists. I definitely need support for the latest MySQL database server and I am thinking of writing an HTTP server specifically for Gambit to form part of the web framework. I am looking to build a web framework on the same level as Rails, only I want to be programming in Scheme. So I need 2 questions answered: 1) Is there any interest in something like this? 2) Does MySQL5 bindings exist for Gambit? (if not I will gladly write them) I am also interested in expanding Gambit's libraries, so there is no problem for me to write libraries/bindings for various things.. I really like Gambit and would really like to see and hear more about Gambit being used in enterprise applications. Gambit is great. Thanks Marc! Kind Regards Rouan ___________________________________________________________ Want ideas for reducing your carbon footprint? Visit Yahoo! For Good http://uk.promotions.yahoo.com/forgood/environment.html

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Could use hackers to try gambit with development version of gcc
by Bradley Lucier 02 Nov '07

02 Nov '07

Over the years I've spent some time building gambit with development versions of gcc; the gcc developers have been quite helpful in fixing bugs and removing inefficiencies uncovered by this testing before the official releases of gcc. There is some interest in using automatically-generated C code, like the code that gsc produces, as "extreme" test cases for gcc's internal algorithms. Because of the timing of future linux releases, gcc-4.3.0, the next major release of gcc, will likely go into fedora, Open Suse, and a few other linux releases. I've started using it to compile gambit just to see what happens. For example, I found one important loop that was compiled to significantly slower code by development 4.3.0 than by the released 4.2.2 on x64-64, and I think that this will likely be fixed before release. Problems that arise in the development version of gcc that used to work in previous versions are quite likely to be fixed before release. I just tried development gcc-4.3.0 on powerpc-apple-darwin8.10.0 (i.e, MacOS X 10.4.10 on powerpc) in 64-bit code and I got a segfault in the garbage collector when trying to calculate (expt 3 10000000). (I just tried it in 32-bit code and got segfault in a different place in the garbage collector.) Perhaps I'm just feeling older and more tired than usual, but I sure would feel better if some other people downloaded the svn sources of gcc, built it, and tried building and testing gambit with it. (I looked at that GC segfault and the wind just went out of me.) Instructions for downloading the svn development version of gcc are at http://gcc.gnu.org/svn.html under "Using the SVN repository". You'll need to install a relatively recent version of gmp and mpfr. I build and configure gcc for the purposes of gcc testing with ../../mainline/configure --prefix=/pkgs/gcc-mainline --enable- languages=c --enable-checking=release --with-gmp=/pkgs/gmp-4.2.2 -- with-mpfr=/pkgs/gmp-4.2.2 and then make bootstrap It's not entirely trivial, but it may be of interest to some people who are into this kind of thing. Brad

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Fw: Web Framework for Gambit
by Rouan van Dalen 01 Nov '07

01 Nov '07

Hi. I am a newbie in scheme, but have been programming for about 7 years. I specialize in web application development and I am really interested in writing a web framework specifically for the Gambit scheme system. I was wondering what your thoughts are on this and if something like this already exists. I definitely need support for the latest MySQL database server and I am thinking of writing an HTTP server specifically for Gambit to form part of the web framework. I am looking to build a web framework on the same level as Rails, only I want to be programming in Scheme. So I need 2 questions answered: 1) Is there any interest in something like this? 2) Does MySQL5 bindings exist for Gambit? (if not I will gladly write them) I am also interested in expanding Gambit's libraries, so there is no problem for me to write libraries/bindings for various things. I really like Gambit and would really like to see and hear more about Gambit being used in enterprise applications. Gambit is great. Thanks Marc! Kind Regards Rouan ___________________________________________________________ Yahoo! Answers - Got a question? Someone out there knows the answer. Try it now. http://uk.answers.yahoo.com/

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Re: [gambit-list] Could use hackers to try gambit with development version of gcc
by Bradley Lucier 01 Nov '07

01 Nov '07

I forgot to CC the list ... On Nov 1, 2007, at 7:46 AM, Bradley Lucier wrote: > > > On Nov 1, 2007, at 6:48 AM, naruto canada wrote: > >> >> I'm getting heap overflow with gambit-c v4.0.0 gcc-3.4.6 : >> >> root@localhost: /usr/v4.0.0/bin/gsi >> Gambit v4.0.0 >> >>> (expt 3 10000000) >> *** ERROR IN ##make-string -- Heap overflow >> 1> >> >> I guess this is not the same as segfault. > > On a 32-bit gambit, converting this number to a string will result > in a string that's larger than the largest allocatable scheme object.

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shift/reset with *correct* dynamic environment
by James Long 01 Nov '07

01 Nov '07

Hello everyone, I have been studying delimited continuations recently. After being blissfully enlightened, I really wanted to have them in Gambit (with a *correct* dynamic environment). I wasn't sure if this was possible non-natively though (at least safely), because Gambit's dynamic environment is somewhat complex, and I have to be able to destructively manipulate the dynamic environment to make sure the delimited continuation truly has its own dynamic environment "slice". However, I figured out how to (hopefully safely) manipulate Gambit's dynamic environment, and I have a full implementation of shift/reset running in Gambit. This implementation is based off Oleg Kiselyov's work; his paper is here: http://okmij.org/ftp/Computation/dynamic-binding.html#DDBinding I am not sure of the performance implications of the Gambit version of shift/reset. I am unhappy with how much has to happen per reset or shift, but such is the cost of a non-native implementation. Unfortunately it goes against the grain of Gambit; after looking at some of Gambit's internals, Marc obviously has fine-tuned the code to be very efficient, and each reset or shift call is quite heavy compared to call/cc. Marc... what are thoughts on a native implementation of shift/reset? I included some tests which show that the dynamic environment does act the way we expect. If you are a zipped tar kind of guy: http://james.tech.coptix.com/files/shift-reset-gambit/shift-reset-gambit.ta… Or you just want the files: http://james.tech.coptix.com/files/shift-reset-gambit/shift-reset-fixed.scm http://james.tech.coptix.com/files/shift-reset-gambit/shift-reset-broken.scm http://james.tech.coptix.com/files/shift-reset-gambit/tests.scm "shift-reset-fixed.scm" contains the full shift/reset implementation. "shift-reset-broken.scm" contains a naive implementation with a broken dynamic environment. "tests.scm" has some tests to show how the dynamic env is fixed. Note that at the top you can include "shift-reset-broken.scm" instead of the fixed version to see how the dynamic env would normally be broken. James -- ; tests.scm (include "shift-reset-fixed.scm") (define var (make-parameter 5)) (define (displine) (disp "--------------------")) (define (disp . rest) (apply print (append rest '("\n")))) (define (dispv . rest) (print rest) (print "\n" (var) "\n")) (define (test f) (let ((k (f))) (k disp))) (define (test-parameterize f v1 v2) (parameterize ((var v1)) (let ((k (f v2))) (k dispv)))) (define (parameterize-no-shift v) (reset (parameterize ((var v)) (print "v: " (var)))) (disp ", v: " (var))) (define (parameterize-it-outside v) (parameterize ((var v)) (reset (dispv "inside reset") ((shift f (dispv "outside of reset") f) "inside reset again") (dispv "last time in reset")))) (define (parameterize-it-inside v) (reset (parameterize ((var v)) (dispv "inside reset") ((shift f (dispv "outside of reset") f) "inside reset again") (dispv "last time in reset")))) (define (wind-outside) (call/cc (lambda (k) (dynamic-wind (lambda () (disp "in winding")) (lambda () (k (reset ((shift f f) "in reset")))) (lambda () (disp "in unwinding")))))) (define (wind-inside) (reset (dynamic-wind (lambda () (disp "winding")) (lambda () ((shift f f) "inside dynamic-wind")) (lambda () (disp "unwinding"))))) (disp "Testing RAW RESET...") (parameterize-no-shift 20) (displine) (disp "Testing OUTSIDE PARAMETERIZE...") (test-parameterize parameterize-it-outside 10 11) (displine) (disp "Testing INSIDE PARAMETERIZE...") (test-parameterize parameterize-it-inside 10 11) (displine) (disp "Testing OUTSIDE WINDING...") (test wind-outside) (displine) (disp "Testing INSIDE WINDING...") (test wind-inside) ; The previous tests output what we expect: Testing RAW RESET... v: 20, v: 5 -------------------- Testing OUTSIDE PARAMETERIZE... inside reset 11 outside of reset 11 inside reset again 10 last time in reset 10 -------------------- Testing INSIDE PARAMETERIZE... inside reset 11 outside of reset 10 inside reset again 11 last time in reset 11 -------------------- Testing OUTSIDE WINDING... in winding in unwinding in reset -------------------- Testing INSIDE WINDING... winding unwinding winding inside dynamic-wind unwinding

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Can gambit-c fulfill this requirement?
by naruto canada 31 Oct '07

31 Oct '07

hi Can gambit-c fulfill this requirement? Let's say I have to implement some numerical library, and given some C headers files and description for what the library should do, and the C interface can not be changed for binary compatibility and ABI reason. The library is simply numerical and no IO or system call allowed (except malloc, free, and fprintf for debug). Can Hobbit generate C code that is suitable for linking and embeding in other project? There is no need for an interpreter. Thanks

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Experience integrating R6RS-style macros and modules into gambit
by Bradley Lucier 30 Oct '07

30 Oct '07

I'd like to hear people's experiences in integrating R6RS-style macros and modules into gambit, either with Abdulaziz Ghuloum's implementation http://www.cs.indiana.edu/~aghuloum/r6rs-libraries/ or Andre van Tonder's implementation http://www.het.brown.edu/people/andre/macros Brad

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Debugging define-macros
by Christopher Diggins 26 Oct '07

26 Oct '07

I was wondering if anyone could suggest a method of debugging "define-macro" expressions so that I can see what is actually being generated by the macro system (e.g. by preventing evaluation of the resulting macro, and printing it)? Otherwise I get a cryptic messages like "unbound unquote", and "ill-formed expression", but without any hints what is causing the grief in the generated code. Thanks, Christopher Diggins

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Tab completion
by Marc Feeley 18 Oct '07

18 Oct '07

I have added tab-completion to the builtin input line editor. When you press tab, the editor will extract the name preceding the cursor and search the symbol table for the lexicagraphically following symbol which will replace the original name. Pressing tab again will find the next symbol, and so on until the set of acceptable symbols is completely enumerated. Just get the latest changeset from the Gambit repository and run "make". Marc

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SRFI's for newbies
by Christopher Diggins 15 Oct '07

15 Oct '07

Hello, Warning: bumbling noob alert. I'm a new Gambit user, and new to Scheme, and I am somewhat familiar with SRFI's as being a suggested library for Scheme implementers but I can't find a list of which SRFI's are supported by Gambit. Scanning the documentation I found reference to the following SRFI's: SRFI-0 SRFI-6 SRFI-12 SRFI-18 SRFI-22 SRFI-33 SRFI-34 SRFI-27 SRFI-39 Is this a complete list? Would it be useful someone (perhaps myself) put this list up on the Wiki? What is the best way to get an unimplemented SRFI? For example, this one interests me: http://srfi.schemers.org/srfi-1/srfi-1.html . Should I just download the linked Scheme file from the SRFi file? Is there any particular reason why this or other SRFI's are not included in the distribution, or did I just overlook them? Sorry to ask so many questions, but it will help me get up to speed on the culture and eventually become a useful contributing member of this community. :-) Any help would be much appreciated. - Christopher Diggins

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