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rewriting a macro
by lowly coder 07 Fév '09

07 Fév '09

in the following code: (define-macro (assert-equal lhs rhs) (let ((g-lhs (gensym)) (g-rhs (gensym))) `(let ((,g-lhs ,lhs) (,g-rhs ,rhs)) (if (not (equal? ,g-lhs ,g-rhs)) (raise (list ',lhs '= ,g-lhs '<> ,g-rhs '= ',rhs)))))) used like this: (assert-equal (+ 1 2) (- 3 4)) is there anyway to rewirte that last line: (raise (list ...)) somehow in the format of: (raise '(....))

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Question about garbage collections
by Bradley Lucier 07 Fév '09

07 Fév '09

Marc: When I do the following: > (##gc-report-set! #t) > (define a (time (random-f64vector 10000000)))(define a (time (random-f64vector 10000000)))(define a (time (random-f64vector 10000000)))(define a (time (random-f64vector 10000000)))(define a (time (random-f64vector 10000000)))(define a (time (random-f64vector 10000000)))(define a (time (random-f64vector 10000000)))(define a (time (random-f64vector 10000000)))(define a (time (random-f64vector 10000000)))(define a (time (random-f64vector 10000000)))(define a (time (random-f64vector 10000000)))(define a (time (random-f64vector 10000000)))(define a (time (random-f64vector 10000000)))(define a (time (random-f64vector 10000000)))(define a (time (random-f64vector 10000000)))(define a (time (random-f64vector 10000000)))(define a (time (random-f64vector 10000000)))(define a (time (random-f64vector 10000000)))(define a (time (random-f64vector 10000000)))(define a (time (random-f64vector 10000000))) then the gc reports are > *** GC: 75 ms, 1.71G alloc, 382M heap, 76.4M live (20% 55696+80018000) > *** GC: 64 ms, 2.01G alloc, 382M heap, 76.4M live (20% 55696+80018000) > *** GC: 64 ms, 2.31G alloc, 382M heap, 76.4M live (20% 55696+80018000) > *** GC: 64 ms, 2.61G alloc, 382M heap, 76.4M live (20% 55696+80018000) > *** GC: 64 ms, 2.91G alloc, 382M heap, 76.4M live (20% 55696+80018000) but after the computations are over I get > (##gc) *** GC: 28 ms, 2.98G alloc, 153M heap, 76.4M live (50% 54064+80018000) > So during the computation the heap size is set to five times the live size, which I did not expect, and after the computation the heap size is set to only twice the live size, which I did expect. What behavior should I expect from the gc? Setting the heap to five times the live size seems pretty extreme. Brad

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##namespace
by lowly coder 06 Fév '09

06 Fév '09

where, if anywhere, is the ##namespace function documented? $ cat gambit-c.txt | grep namespace `ill-formed-namespace' Ill-formed namespace `ill-formed-namespace-prefix' Ill-formed namespace prefix `namespace-prefix-must-be-string' Namespace prefix must be a string `ill-placed-**namespace' Ill-placed '##namespace'

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Re: [gambit-list] dynamic scope
by Marc Feeley 05 Fév '09

05 Fév '09

On 31-Jan-09, at 11:44 PM, lowly coder wrote: > Great, the following works: > > cat test.scm > (define (foo x) (* x 2)) > > (define (g x) (foo x)) > > > (pp (g 2)) > (pp > (let ((old-func '())) > (dynamic-wind > (lambda () > (set! old-func foo) > (set! foo (lambda (x) (* x 3)))) > (lambda () (g 2)) > (lambda () (set! foo old-func))))) > > (pp (g 2)) > > 4 > 6 > 4 > > two questions: > 1) can anything go wrong with variable capture / aliasing? > [intuitively, I believe no, so long as I don't use 'old-func' in my > thunk > 2) is there a more elegant/idiomatic way to do this? In terms of elegance I prefer this (which eliminates all variable capture problems): (let ((thunk (lambda () (g 2))) (new-foo (lambda (x) (* x 3))) (old-foo foo)) (dynamic-wind (lambda () (set! foo new-foo)) thunk (lambda () (set! foo old-foo)))) But once again this will not work right if multiple threads are dynamically scoping foo simultaneously, but the parameterize based approach will work fine. Marc

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Bug involving syntax-rules and c-lambda
by David Rush 04 Fév '09

04 Fév '09

Hi there, I decided that it would be good to make sure that I am up-to-date with Gambit 4.4 before I posted my web framework here for those who have expressed an interest and I am finding a destructive interaction when using the c-lambda form. With the code in the sequel and Gambit 4.4.0, if I compile thusly: $ gsc -:s -link bug.gambit *** ERROR IN MAP -- invalid syntax () but it compiles fine if I omit the -:s option. Now obviously, the example does not require syntax-rules macros, but the full framework certainly does. Is there a known incompatibility here? The text concerning define-syntax hints at such a possibility, but the actual interaction is unclear. david -- GPG Public key at http://cyber-rush.org/drr/gpg-public-key.txt ; Null module for: Prelude (c-declare " #include <sys/time.h> #include <time.h> ") (c-define-type timeval (struct "timeval")) (c-define-type timeval* (pointer timeval)) (define make-timeval (c-lambda () timeval* "___result_voidstar = ___EXT(___alloc_mem)(sizeof(struct timeval));")) (define timeval.tv_sec (c-lambda (timeval*) int32 " ___result = ___arg1->tv_sec;")) (define timeval.tv_usec (c-lambda (timeval*) int32 "___result = ___arg1->tv_usec;"))

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webapp
by lowly coder 02 Fév '09

02 Fév '09

hey all, i'm thinking of writing a webapp, the type generally written w/ ruby on rails; but with gambit scheme. given existing tools / termite, I wanted to see what suggestions people had (the frontend is mainly flash + asynch javascript based, the backend needs to run on ec2; I need some type of database, but I'm not particularly attached to mysql or postgresql) please tell me anything that may be useful thanks!

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Re: [gambit-list] webframework
by Marc Feeley 02 Fév '09

02 Fév '09

On 30-Jan-09, at 10:41 PM, lowlycoder wrote: > can i write web apps using jazz scheme? if so, please give me some > pointers. thanks! You can also try out the Gambit web-server example in examples/web- server and there is also a web server on the Gambit dumping grounds which implements cookies and server pages (http://dynamo.iro.umontreal.ca/~gambit/wiki/index.php/Dumping_Grounds#Full_… ). Marc

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reading list of symbols defined in top level
by lowly coder 01 Fév '09

01 Fév '09

suppose I have test.scm: (define (foo ...) ...) (define (bar ...) ...) (define (yay ...) ...) (some-magical-funcion) --> '(bar foo yay) # is this possible? basically, I want to have some function I can call to get a list of all symbols defined in the current top level

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The future of Gambit
by Bradley Lucier 01 Fév '09

01 Fév '09

I've had a draft e-mail sitting in an IMAP folder for about 8 months with the subject line "The future of Gambit", but with an empty body. Today I still don't know precisely what to put into this body, but at least I found a blog entry that explains a bit of my feelings. I'm not exactly thrilled about the level of "outside" participation in (core) Gambit development. In fact, graphing the Gambit git commit log would be a parody of the argument in http://www.gnome.org/~michael/blog/ooo-commit-stats-2008.html that the lack of non-Sun developers working on OpenOffice.org is an indicator that it is not a healthy project. For there is only one committer to Gambit, and the best that can be said about getting other developers to develop code for Gambit is that a very few times Marc has committed code he hasn't written himself. I've studied the Gambit source code a bit, and even made some contributions over the years, but Marc's programming style is something I have not seen elsewhere---highly macroized and layered, there are patterns in the coding techniques but not ones that I've been able to unravel in general. Perhaps one way to help new developers get into Gambit would be fore Marc to take a subsystem and write down an explanation of how the macros and layers of code for types, exceptions, constructors, functions, ... of that subsystem work. (Christian Jaeger seems to have had some success in doing this, but it would be good to have an explanation of how Marc sees the construction of subsystems of the runtime.) Just to get an idea of Marc's programming style would allow others to divine more easily the structure of the code. And happy holidays to everyone! Brad

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dynamic scope
by lowly coder 01 Fév '09

01 Fév '09

is there anyway i can obtain dynamic scoping in gambit? lexically scoping is really cool, and I want it as the default behavior; i just want the ability to go: (define (foo x) (* x 2)) (define (g x) (foo x)) (pp (list (g 1) (dynamic-let ( (foo (lambda (x) (* x 3)))) (g 1)))) to get me: (2 3)

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