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Questions about reading from a port and u8vector
by Lam Luu 29 Jui '09

29 Jui '09

Hello everyone, I am working on ICFP programming contest. There is something I am really confused about. Supposed that I have an input port, and I want to read the next 8 bytes as an IEEE 754 double value or a 32-bit unsigned integer, is there anyway to do this in Gambit? I mean, they are not string with digit '0' - '9', but actual representation of the number. Secondly, is there anyway to pass an u8vector to a C-lambda, as a char* or whatever? The C Interface section of the manual only provides information about character string, but not u8vector. Is it possible to pass u8vector as char*? Thank you very much, Lam Luu

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reading file into string / length of file
by lowly coder 29 Jui '09

29 Jui '09

I want to read a file into a string. After I open it up, is there a way to get the length of the file? (or even before I open it up?) I see that we have read-substring and read-u8vector Currently, the best solution appears to be ... do a read-u8vector on it, get it's string length, then re-open the file and do a read-substring on it ... surely there's something more elegant. :-) Thanks!

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overload pp for define-types
by lowly coder 28 Jui '09

28 Jui '09

Is there a way to overload pp for define-types? (maybe some undocumented arg in (define-type ...) ?) I would like to change how they're printed. Also, can I override existing ones, like f32vector? When I have something that's 1000 f32's, I'd prefer an output of <#f32vector ...> rather than all 1000 elems. Thanks! (If not, I'll just define a separate command like pp2 and use that instead, but overloading pp somehow seems more elegant).

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heapoverflows
by lowly coder 28 Jui '09

28 Jui '09

I understand the when I get a heapoverflow, gambit can't pop me into a REPL (since that'll take more heap). However, can I get a dying process to print out a backtrace for me? (Increasing the maximum heap size won't solve this problem -- the problem is that I have some run away code that is consuming up all the memory, and if I increase the max heap size, all that happens is that it just makes it longer to heap overflow). [I debugged the last one manually by trying pieces of code here & there; but if I could get a backtrace, it'd just be so much faster] Thanks!

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call on gc
by lowly coder 28 Jui '09

28 Jui '09

Is it possible to have an object X so that some function gets called when X is gc-ed? Suppose I have something like (define-type foo ...) (define bar (foo-create ...)) and inside of bar, there's a C-land resource that I want to have freed up when bar is GC-ed; Is there a way to have some function like (foo-gc) s.t. when bar is GC-ed, (foo-gc bar) is called? Thanks!

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Employment opportunities in Gambit / JazzScheme
by Guillaume Cartier 28 Jui '09

28 Jui '09

Hi everyone, Auphelia Technologies is looking for highly skilled resources for work in Gambit / JazzScheme, Web development and Database architecture. Auphelia Technologies offers integrated management software, entirely customized for small and medium-sized businesses, using innovative technology and revolutionary features. Auphelia is located in Montreal, Canada. See http://www.auphelia.com (under construction). Gambit is a complete, portable, efficient and reliable implementation of the Scheme programming language. See http://dynamo.iro.umontreal.ca/~gambit. JazzScheme is an open source programming language and cross-platform framework built on top of Gambit . It includes a sophisticated IDE and has been used for more than 10 years to develop high-quality commercial software. See http://www.jazzscheme.org. DESCRIPTION OF THE PROJECT We are starting development on a new Enterprise Resource Planning (ERP) software that we plan on making top of its class. Work will be a complete rewrite and a major evolution of an existing product already in use by a large client base. Note that this project is a highly complex undertaking as we will not be developing just another ERP software but a complete dynamic ERP creation platform. Project is planned to last around 1 1/2 year for the first release. Current team is composed of 10 people and is planned to grow to around 25. TECHNOLOGIES After an exhaustive evaluation period, decision has been made to develop the backend entirely in Gambit / JazzScheme. We still haven't decided between Qt and JazzScheme for our desktop client solution but if the JazzScheme platform can be evolved to suit our needs, we have a definite preference for using it accross the whole project. EMPLOYMENT OPPORTUNITIES We need resources for the following 4 positions : LANGUAGE / FRAMEWORK DEVELOPPER 1 or 2 resources to work closely with Gambit and JazzScheme's authors to evolve the JazzScheme langage and framework during a period of about 6 months. Planned work includes : - Language - Module / build system - Performance / memory - IDE / Remote debugger - X11 and MacOS X frontends Note that Gambit's author Marc Feeley, has confirmed his participation part time in the project! Ideally, the resources we are looking for would have expert knowledge in Lisp, Scheme, Gambit and JazzScheme! But realisticaly, if you don't know those but are brilliant, motivated and want to be part of an exciting project that could put Scheme to the forefront, please send us your resume! PROJECT DEVELOPPER 1 or 2 resources to complete our existing team and work on the Desktop client and / or Server layer. Knowledge of the following is a definite plus : - Lisp, Scheme, Gambit, JazzScheme - GUI development - Highly scalable server development - Databases, SQL WEB DEVELOPPER 1 resource to work on the Web client. We need a world class expert in advanced web interfaces as the Web client will have to implement all the functionality of the Desktop client. Knowledge of the following is critical : - Dynamic web development with AJAX - Advanced web interfaces - Javascript - PHP DATABASE ARCHITECT 1 resource to be lead in every database related work. Knowledge of the following is critical : - World class expertise in database modeling - Databases : PostgreSQL (will probably be the first one supported), Oracle, SQLite (for the offline mode) Ideally we are looking for full time resources located near Montreal but are definitely open to remote work and other options. Auphelia Technologies offers competitive & flexible employment conditions. PS: Please feel free to pass this announce to your friends! Cheers, Guillaume Cartier gc(a)auphelia.com

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file local defines
by lowly coder 27 Jui '09

27 Jui '09

; foo.scm (magical-define x 100) ; bar.scm (define y (+ x 10)) ; ; all.scm (load "foo") (load "bar") ; <-- I want this here to be a syntax error Is there a way I make defines/variables _local_ to a single *.scm file? I promise to not 'include it, and only 'load it. In essence, I'm looking for the equiv of static vars in C. What I don't want to do is something like: ;foo .scm (lambda () ... all of foo.scm ) ; ... since there are other parts of foo.scm that I do want to be visible. Yes, I do realize that what I'm asking for sounds like the basics of a module system. Thanks!

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gsi behaves differently from gsi -:s
by Marijn Schouten (hkBst) 26 Jui '09

26 Jui '09

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi, $ gsi Gambit v4.4.3 > (let ((else #f)) (cond (else #t))) #t > (let ((else #f)) (cond (else #f) (#t #t))) *** ERROR IN (console)(a)2.24 -- Else clause must be last ============================ $ gsi -:s Gambit v4.4.3 > (let ((else #f)) (cond (else #t))) > (let ((else #f)) (cond (else #f) (#t #t))) #t > Marijn - -- If you cannot read my mind, then listen to what I say. Marijn Schouten (hkBst), Gentoo Lisp project, Gentoo ML <http://www.gentoo.org/proj/en/lisp/>, #gentoo-{lisp,ml} on FreeNode -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.12 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAkpEpqwACgkQp/VmCx0OL2xXsQCffn2yMAVzYmSZtePwemP2qLe4 1EMAnikw/JkfiRzODOeQk44Yt7iSWz+f =euz6 -----END PGP SIGNATURE-----

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load -> re-compile if out of date
by lowly coder 24 Jui '09

24 Jui '09

A common problem I'm recently having is: foo.scm <-- contais c-define-type --> compiles to foo.o1 Some other code says (load "foo") Now, something changes (mostly a git thing) and foo.scm 's timestamp changed, and my code compalins taht c-define-type can't be used in interpreted mode. Is there a gambit command for "recompile this if out of date, with options XYZ"? Thanks!

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Garbage Collection BlackMagic
by lowly coder 23 Jui '09

23 Jui '09

Maybe the right answer is "Don't do this in Gambit", but I'd like to give it a try: I'm writing an application, in Gambit. It does OpenGL graphics. It runs at 100fps. It's interpreted. Now, put down the pitch fork -- the only thing it's doing at 100Hz is for 20 different objects glLoadIdentity glPushMatrix some rotation glCallList glPopMatrix This works fine, _except_ when I get hit with a gambit gc, it costs me like 70ms ... which becomes a noticable lag in my otherwise smoothly rotationg screen. What are my options? Can I get a thread local heap? My basic usage is the following: launch gambit app --> it opens up a glut window --> it listens on port ABCDE for new graphics primitives in my editor window, I type some code; I send new primitives to port ABCDE; my gambit app spends a bit of time building it into a new display list That's all. What can I do in this particular situation? Thanks!

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