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dumb question: outputting in hex format
by lowly coder 23 Jui '09

23 Jui '09

I know that #xdeadbeef lets me input in hex, but is there something like C's fprintf(stderr, "%x"); ? Thanks!

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web-repl.scm / concurrent read/writes
by lowly coder 23 Jui '09

23 Jui '09

Looking at the web-repl.scm file in gambc/examples, I often see situations of: lock mutex write single char flush output unlock mutex Why is this necessary? According to the gambit documentation, ports have to be written to handle concurrent read/writes themselves. Thanks!

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calling scheme from C
by Aditya Godbole 22 Jui '09

22 Jui '09

Hi, I'm trying to call functions written in scheme from C. I saw the server.scm and client.c as mentioned in docs, but I could not quite understand what it was doing. I also could not successfully link the application. Where can I find documentation for the ___setup function and the steps for compiling such a program? TIA. Aditya.

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defining my own input/output ports
by lowly coder 22 Jui '09

22 Jui '09

As I get more familiar with Gambit, I find it's notion of ports to be really really useful. However, I don't know how to create these structures myself. Can someone point me to some sample code? A really great example would be something like: (define-type tagged-data tag data) then, as a piece of data is written to the output port, it's tagged with a (increasing number), and when it's read off the input port, it's a piece of tagged data so ssuppose I wrote 'a 'b 'c 'd 'e to the port then when I read from it, I get back (make-tagged-data 1 'a) (make-tagged-data 2 'b) ... (make-tagged-data 5 'e) The point of this isn't this particular problem, but to understand what abstractions I need to provide when writing my own ports. Thanks!

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problem with gsc and .gambcini
by Aditya Godbole 22 Jui '09

22 Jui '09

Hi, I'm getting some quirky behaviour with gsc and .gambcini, in which I am initialising the black hole system. [ffi]$ cat server.scm (c-define (add-two n) (int) int "add_two" "extern" (+ 2 n)) [ffi]$ cat ~/.gambcini (load "~~/lib/modules/build") [ffi]$ gsc server.scm *** ERROR IN "/home/aditya/prog/scheme/ffi/server.scm"@1.24 -- Undefined C type identifier Now if I comment out the (load ...) in .gambcini and put a line in server.scm - [ffi]$ cat server.scm (load "~~/lib/modules/build") (c-define (add-two n) (int) int "add_two" "extern" (+ 2 n)) [ffi]$ cat /home/aditya/.gambcini ;(load "~~/lib/modules/build") [ffi]$ gsc server.scm [ffi]$ which works without problems. I am using gambit v4.4.3 Can someone please explain why this happens? -aditya

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backtrace fun
by lowly coder 21 Jui '09

21 Jui '09

~/test$ gsi test.scm -e "(a)" *** ERROR IN a, "test.scm"@1.23 -- Unbound variable: b ~/test$ gsi test.scm -e "(run)" #f #("/home/x/test/test.scm" 1441792) #("/home/x/test/test.scm" 1048576) #("/home/x/test/test.scm" 786432) #f #((string) 0) #f #f 25 ~/test$ cat test.scm (define (a) (pp (+ 20 b))) (define (run) (let ((old-handler (current-exception-handler))) (with-exception-handler (lambda (e) (with-exception-handler old-handler (lambda () (##continuation-capture (lambda (old-cont) (do ;((cur-frame cont (##continuation-next-frame cur-frame #t))) ((cont old-cont (##continuation-next-frame cont #t))) ((not cont)) (pp (##continuation-locat cont))) (##continuation-return old-cont 5))) ))) (lambda () (a))))) Why is it ... that when I print out the continuations by frame, I can't get the data that I want (which ##cmd-b apparently does get, which is: test.scm, line 1, character 23). This baffles me. (I'm trying to write a gambit debugger in gambit, teehee) Thanks!

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multithreaded debugging fun
by lowly coder 21 Jui '09

21 Jui '09

Please see typescript (sorry, copy/paste not working in X right now) i have test.scm, which forks off a thread (<thread #2>) which forever does: (pp 'yay); so I can see it print (+ "asdf" 1) ; just to generate an error I'm running gsc with -:dar, so i want debugging support, for all threads, and get thrown into a REPL when an error occurs. Here are my questions: 1) in my primordial thread, why do I have to execute some command (like "(void)") before I get thrown into the REPL in thread2? if everything is running concurrently, why does the error in thread2 not pop up immediately and get me thrown into a REPL? 2) in thread 2, after hitting ,(c 0) ... why don' i immediately get an "yay"? (if it's continuing from that error, it should jump back to the (pp 'yay)) 3) after printing said 'yay', why do I have to hit (void) in the thread #1 before getting the error repl in thread 2? why doesn't the error immediately happen 4) it seems like i'm ping-ponging between the two threads on the REPL. Is there anyway I can control this myself? (i.e. some command to jump me to thread1, some to jump me to thread2?) Thanks!

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New Gambit Mailing Lists
by James Long 20 Jui '09

20 Jui '09

Hey guys, Marc has set up 2 new gambit mailing lists for us: * gambit-iphone: specifically for iphone development on gambit https://webmail.iro.umontreal.ca/mailman/listinfo/gambit-iphone * gambit-ffi: for FFI discussions, especially work on automatically generating FFI's https://webmail.iro.umontreal.ca/mailman/listinfo/gambit-ffi The reason we've separated these from the main mailing list is that a good bit of work needs to be done on both fronts, and people involved can send a bunch of minor emails around without cluttering the main list. Please join these lists if you are interested in following or developing either of these aspects of Gambit. I'll be out of town for the next week so I won't be sending any messages to them then. - James

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Running Gambit on Ubuntu 9.01
by Alfonso Urroz 19 Jui '09

19 Jui '09

Hello there, using Synaptic I downloaded all the required files for Gambit-C. Now, what do I do to in order to use it? So I can edit/run programs. Thanks for any help or advice. Alfonso Urroz

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How to do pipe?
by Lam Luu 19 Jui '09

19 Jui '09

Hello all, Is there anyway to open a pipe to a new process (On Unix)? You know, like popen in C. I have searched through the manual, but could not find anything there. Thank you, Lam Luu

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