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Gambit Readtables
by Guillaume Cartier 19 Jui '07

19 Jui '07

I am trying to have my reatable recognize extra named chars like #\Home, #\End, ... but there's something I don't get... In the following code: ---------------------- (include "~~/src/lib/header.scm") (define extra-named-chars '(("Nul" . #\x00) ("Home" . #\x01) ("Enter" . #\x03) ("End" . #\x04))) (define (add-extra-named-chars! readtable) (macro-readtable-named-char-table-set! readtable (append (macro-readtable-named-char-table readtable) extra-named-chars))) (define (make-my-readtable) (let ((readtable (##readtable-copy ##main-readtable))) (add-extra-named-chars! readtable) readtable)) (define (tr) (add-extra-named-chars! ##main-readtable)) (define (tr2) (set! ##main-readtable (make-my-readtable))) ---------------------- If I do (tr) then everything works perfectly, but using tr2 doesn't work, I get Invalid '#\' name: "End" Any clue? Thanks, Guillaume Cartier

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Newbie Question: define-syntax and syntax-rules
by Gabriel Kronberger 17 Jui '07

17 Jui '07

Hi, This is probably a silly question but I'm having major troubles with define-syntax or syntax-rules. I used to work with the gambit debian packages version 4.0b20 however it seems the necessary files (syntax-case.scm ...) are missing from the package. So I complied and installed 4.0b22. Now I can load the syntax-case.scm file however it seems I can't get a simple syntax definition to work. Even the simple example from the Gambit-C documentation doesn't work. Gambit Version 4.0 beta 22 > (load "~~syntax-case") "/usr/local/Gambit-C/4.0b22/syntax-case.scm" >(define-syntax unless (syntax-rules () ((unless test body ...) (if test #f (begin body ...))))) *** ERROR IN (console(a)3.15 -- Ill-formed expression Unfortunately i couldn't find information on this problem in the documentation or the archives so i'm kinda stuck now. Any help is appreciated. Thanks, Gabriel

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Profiling scheme + C programs
by Phil Dawes 15 Jui '07

15 Jui '07

Hi Gambit List, I've got a gambit program which includes some C code for searching memory mapped files and I was wondering how best to profile it. I've used statprof, but since it works using gambit interrupts it doesn't statistically highlight time spent in functions containing C code. I've been using a 'define-timed' macro I wrote (see below) which records the accumulated wall-time a function uses. This is fine, but it means you have to instrument each function manually (by changing '(define (foo) ..) to '(define-timed (foo) ..)' which is a bit sucky. Could this be modified to instrument each function automatically? (I tried redefining 'define' but couldn't get this to work cleanly) Is there a better way? Many thanks, Phil --------- (define *timerhash* (make-table)) (define (reset-timer) (set! *timerhash* (make-table))) (define (accum-time name thunk) (let* ((timebefore (real-time)) (res (thunk))) (table-set! *timerhash* name (+ (table-ref *timerhash* name 0) (- (real-time) timebefore))) res)) (define (get-times) (map (lambda (e) (set! total (+ total (cdr e))) (cons (car e) (* 1000 (cdr e)))) (sort-list (table->list *timerhash*) (lambda (a b) (> (cdr a) (cdr b)))))) (define-syntax define-timed (syntax-rules () ((define-timed (name . args) body ...) (define (name . args) (accum-time 'name (lambda () body ...))) ))) -------- Usage: (define-timed (myfunction) (do stuff)) (reset-timer) ;...do stuff (myfunction) ;... (get-times)

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Termite and Windows
by Nathan Wong 15 Jui '07

15 Jui '07

Thanks for the quick response. When I use Cygwin, "./configure" seems to run fine, but "make boostrap" fails. It says "gcc: no input files". I'm using mingw32-make.exe. - Nathan

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Gambit's Linking Model
by Guillaume Cartier 14 Jui '07

14 Jui '07

Hi everyone, Unfortunately, I think I have stumbled upon a major problem for my project with the linking model of Gambit / Scheme's lack of specification for linking code. For my applications I absolutly need the ability to be able to load code selectively. If I understand correctly, the Gambit linking model is that all classes compiled into a .exe are loaded upon launching the .exe so that cannot do for me. The only alternative I see is the use of .o1 loadable code but is it reasonable to dynamically load like 1000+ .o1 files? Wouldn't launching incur a huge penalty in speed / space vs a selfcontained .exe as every .o1 is a full fleged dynamic library? Also, with this approach, distributing to my clients a folder containing 1000 .o1 files is everything but nice. I could zip them together a bit like interpreted languages like Python do but then I don't think Windows or Gambit or ... can load .o1 files from a zip directly so I'd have to unzip them to a temp folder which is again not very tempting. Any help / thoughts really appreciated. This is criticaly for my using Gambit for my project. Thanks, Guillaume

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gambit cgi error 11
by |/|/ Bendick 14 Jui '07

14 Jui '07

Hi, I'm trying to use gambit 4.0b22 for CGI but am having a problem. A simple script: #!/usr/local/Gambit-C/current/bin/gsi-script (define (main . args) (display "Content-type: text/html\n\nhi\n\n") (force-output (current-output-port)) 0) But I get a "500 - Internal Server Error" every time I try to hit the page. The web server (lighttpd-1.4.15) tells me the script is exiting with a return value of 11 which the gambit manual doesn't document. The script runs fine from command line. If I just throw: #!/bin/sh echo "Content-type: text/html" echo "" echo "hi"; into the file, it works correctly so it doesn't look like a permission/configuration/whatever error with the web server. Any ideas on code 11? -- |/|/ Bendick

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Termite and Windows
by Nathan Wong 14 Jui '07

14 Jui '07

Hi, Has anyone successfully gotten Termite running on Windows? If so, would it be possible to provide instructions for compiling or even the libraries/binaries themselves? Thanks, Nathan Wong

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Debugging macros
by Guillaume Cartier 10 Jui '07

10 Jui '07

If an error occurs during the expansion of a macro, Gambit doesn't start a new repl to enable me to debug the code. Is there a way to enable this? It would be really helpfull for me as some of my macros are really complex. For instance: Gambit Version 4.0 beta 22 > (define-macro (foo) (car 1)) > (foo) *** ERROR -- (Argument 1) PAIR expected (car 1) > Thanks, Guillaume

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Re: [gambit-list] [erlang-questions] Scheme on the Erlang VM
by Marc Feeley 05 Jui '07

05 Jui '07

On 4-Jun-07, at 3:03 PM, Luke Gorrie wrote: > "Philip Robinson" <chlorophil(a)gmail.com> writes: > >> On 6/2/07, Joel Reymont <joelr1(a)gmail.com> wrote: >>> >>> What about Scheme on the Erlang VM? >> >> I would *love* a Scheme/Lisp on the Erlang VM. > > For a toy starting point see 'lersp' in the Jungerl. > > The most fun bit of writing a Scheme interpreter IMO is to write > things like lersp/priv/core-macs.ler i.e. to implement 'let', 'case', > 'if', etc from a small kernel. > > Core Erlang would probably make a nice target language for a Scheme > dialect. I just couldn't resist the challenge and wrote a prototype Scheme to Erlang compiler (named Stoe of course) that is based on the front-end of the Gambit-C Scheme compiler. The code is attached below. It is just a prototype and it only handles a subset of Scheme, but it could be the starting point for a more complete Scheme to Erlang compiler. Stoe supports some of the Termite language and mutation of local variables. Here's a sample usage: % cat test.scm (define (fib n) (if (< n 2) 1 (+ (fib (- n 1)) (fib (- n 2))))) (define (fact n) (if (< n 2) 1 (* n (fact (- n 1))))) (define (iota n) (iota-2 n '())) (define (iota-2 i lst) (if (> i 0) (iota-2 (- i 1) (cons i lst)) lst)) (define (tally) (let ((sum 0)) (lambda (x) (set! sum (+ sum x)) sum))) (define (process n dest) (lambda () (! dest (map (?) (iota n))))) (define (main) (let ((a (spawn (process 10 (self)))) (b (spawn (process 10 (self)))) (t1 (tally)) (t2 (tally))) (! a fib) (! b fact) (map t1 (?)) (map t2 (?)) (list (t1 0) (t2 0)))) % gsc -i stoe.scm test.scm % cat test.erl -module(test). -export([fib/1,fact/1,iota/1,iota@2d@2/2,tally/0,process/2,main/0]). fib(N) -> if (N < 2) -> 1; true -> (fib((N - 1)) + fib((N - 2))) end. fact(N) -> if (N < 2) -> 1; true -> (N * fact((N - 1))) end. iota(N) -> iota@2d@2(N,[]). iota@2d@2(I,Lst) -> if (I > 0) -> iota@2d@2((I - 1),[I|Lst]); true -> Lst end. tally() -> Sum = schemelib:box(0), fun (X) -> schemelib:setbox(Sum,(schemelib:unbox(Sum) + X)), schemelib:unbox(Sum) end. process(N,Dest) -> fun () -> (Dest ! lists:map(receive Tmp_1 -> Tmp_1 end,iota(N))) end. main() -> {T2,T1,B,A} = {tally(),tally(),spawn(process(10,self())),spawn (process(10,self()))}, (A ! fun fib/1), (B ! fun fact/1), lists:map(T1,receive Tmp_2 -> Tmp_2 end), lists:map(T2,receive Tmp_3 -> Tmp_3 end), [T1(0),T2(0)]. % erl Eshell V5.5.4 (abort with ^G) 1> c(schemelib.erl). {ok,schemelib} 2> c(test.erl). {ok,test} 3> test:main(). [4037913,231] Marc

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Gambit's Debugger
by Guillaume Cartier 05 Jui '07

05 Jui '07

I added (display-environment-set! #t) to my gambcext.scm thinking it would automate the tedious task of always typing ,e after changing frames in the debugger. It does show the environment after frame changes but seems buggy as what gets displayed is different (and not correct) from what I get if I do an explicit ,e. Is it something I don't understand or a bug? Guillaume

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