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Character out of range
by François Magnan 14 Jui '12

14 Jui '12

Hi, I got the following error in Gambit-C (4.6.4 compiled for iOS) *** ERROR IN (string)(a)1.7862 -- Character out of range What does it mean? Thank you, Francois

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What papers and strategies underly Gambit's design, in particular the compiler & VM?
by Mikael 13 Jui '12

13 Jui '12

Hi, In the purpose of making it clear and easy-enough for the unintroduced to understand the inner workings of Gambit in its current version, it'd be great to know what strategies/philosophies, papers and other reference documents underly Gambit - its compiler, environment and so on, beyond the Scheme (R5RS etc.) and SRFI specs. I'd be happy to make a Wiki page, Theory and papers, or alike, of this. My best understanding is that compilation to C/asm of Scheme with callcc support generally is perceived as a process that's intricate and of an abstract nature, asking this quite a lot therefore. :-) The papers I'm aware of are basically those on Marc's homepage and those listed by Alex below. And, beyond knowing which they are, it'd be great to have a clue of how central the respective paper is in Gambit's particular design / how strictly it was adhered to, on the scale from directly/being implemented as it is to indirectly/used rather for inspiration. Things whose answers can be found in the papers would include: * How the internal value, object, procedure and closure representations look and fit together Closures effectively special-purpose vectors of boxes? All values and object references are internally native-size integers with a number of reserved bytes describing the value type, what about them? * Value and object allocations, made how and what optimizations for fast dead object detection and subsequent reclaim are there * The layout of the asm/C-level stack and trampolines and how the GC resolves the locations of all object reference, anatomy of a procedure call and return * How the CPS transformation works * What optimizations are made, in terms of register use optimizations, compile-time pre-evaluation or deductions of datatype At some point I got that generally |cdr| is translated to +1 in asm/c, for instance * What does the internal form of interpreted code actually look/work like * Interrupt checks, made provenly at what granularity * Code debuggability, made in compiled code on what basis * Motivations for the GVM code's design * Hashtable algorithm * Number handling I suppose there's key areas beyond these also. And, I suppose quite possibly, some key things are not described in any paper. Find below an attempt to figure out which of Marc's papers are in use for these respects of Gambit today. If you know such papers/docs or you see areas beyond those listed above that ought to be considered as in the scope too, please tell. Kind regards, Mikael * Marc Feeley. *Speculative inlining of predefined procedures in an R5RS Scheme to C compiler. *In Olaf Chitil, Zoltán Horváth, and Viktória Zsók, editors, *Implementation and Application of Functional Languages (IFL'07)*, volume 5083 of *Lecture Notes in Computer Science*, pages 237-253, 2008. [PDF] <http://www.iro.umontreal.ca/~feeley/papers/FeeleyIFL07.pdf> * Fernanda Kri and Marc Feeley. *Genetic instruction scheduling and register allocation. *In *International Conference on the Quantitative Evaluation of Systems (QEST'04)*, pages 76-83, 2004. [PDF]<http://www.iro.umontreal.ca/~feeley/papers/KriFeeleyQEST04.pdf> * Marc Feeley. *A better API for first-class continuations. *In *Scheme and Functional Programming Workshop (SFPW'01)*, pages 1-3, September 2001. [PDF] <http://www.iro.umontreal.ca/~feeley/papers/FeeleySW01.pdf> * Danny Dubé and Marc Feeley. *Demand-driven type analysis: an introduction. *In *Scheme and Functional Programming Workshop (SFPW'01)*, pages 21-32, September 2001. [PDF]<http://www.iro.umontreal.ca/~feeley/papers/DubeFeeleySW01.pdf> * Marc Feeley. *A portable implementation of first-class continuations for unrestricted interoperability with C in a multithreaded Scheme. *In *Scheme and Functional Programming Workshop (SFPW'00)*, pages 65-66, September 2000. [PDF] <http://www.iro.umontreal.ca/~feeley/papers/FeeleySW00.pdf> * Mauricio Solar and Marc Feeley. *Scheduling algorithm considering latency time on a shared-memory machine. *In *XVI World Computer Congress, International Conference on Software: Theory and Practice*, August 2000. * Marc Feeley, James S. Miller, Guillermo J. Rozas, and Jason A. Wilson. *Compiling higher-order languages into fully tail-recursive portable C. *Technical Report 1078, département d'informatique et r.o., Université de Montréal, August 1997. [PDF]<http://www.iro.umontreal.ca/~feeley/papers/FeeleyMillerRozasWilsonDIRO1078.…> * Dominique Boucher and Marc Feeley. *Abstract compilation: a new implementation paradigm for static analysis. *In *International Conference on Compiler Construction (CC'96)*, pages 192-207, April 1996.[PDF]<http://www.iro.umontreal.ca/~feeley/papers/BoucherFeeleyCC96.pdf> * Manuel Serrano and Marc Feeley. *Storage use analysis and its applications. *In *ACM SIGPLAN International Conference on Functional Programming (ICFP'96)*, pages 50-61, May 1996. [PDF]<http://www.iro.umontreal.ca/~feeley/papers/SerranoFeeleyICFP96.pdf> * Marc Feeley. *Polling efficiently on stock hardware. *In *ACM Conference on Functional Programming Languages and Computer Architecture (FPCA'93)*, pages 179-187, 1993. [PDF]<http://www.iro.umontreal.ca/~feeley/papers/FeeleyFPCA93.pdf> * Marc Feeley and Guy Lapalme. *Closure generation based on viewing LAMBDA as EPSILON plus COMPILE. **Computer Languages*, 17(4):251-267, 1992. [PDF]<http://www.iro.umontreal.ca/~feeley/papers/FeeleyLapalmeCL92.pdf> Marc Feeley and Guy Lapalme. *Using closures for code generation. **Computer Languages*, 12(1):47-66, 1987. [PDF]<http://www.iro.umontreal.ca/~feeley/papers/FeeleyLapalmeCL87.pdf> * Marc Feeley. *Deux approches à l'implantation du language Scheme. *Master's thesis, Université de Montréal, May 1986. [PDF]<http://www.iro.umontreal.ca/~feeley/papers/FeeleyMSc.pdf> 2011/6/9 Alex Queiroz > Hallo, > > On Wed, Jun 8, 2011 at 11:14 PM, Jason E. Aten <j.e.aten(a)gmail.com> wrote: > > > > If others on the list have pointers to papers as well, I'd enjoy reading > > about the best thoughts on how to implement continuations. > > > > "Representing Control in the Presence of First-Class Continuations" > http://www.cs.indiana.edu/~dyb/papers/stack.ps > > "A portable implementation of first-class continuations for > unrestricted interoperability with C in a multithreaded Scheme" > http://repository.readscheme.org/ftp/papers/sw2000/feeley.pdf > > "Implementation strategies for first-class continuations" > http://www.springerlink.com/content/h5808n962434j275/fulltext.pdf > > More in: > http://library.readscheme.org/page6.html > > Cheers, > -- > -alex >

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___setup memory corruption(?) on iPhone
by Kirill Zorin 11 Jui '12

11 Jui '12

Hi all, I've built (a slow version of) Gambit with llvm-gcc 4.2 on Mac OS X, targeted for the iPhone, using the build-gambit-iOS script, for the iOS 5.1 SDK. (I can't build it with latest clang, because for whatever reason Gambit's configure exits with various autoconf-related errors when clang is used.) When I run ___setup(...) as required, from a separate thread, the function never returns. If I call it from the main thread it returns, except that after that, various Apple libraries begin to crash in mysterious ways. If I don't run ___setup(...) at all (from any thread), everything works fine. (Except, of course, that I can't run Scheme code =)) Any ideas what could be at fault here (i.e. what I'm doing wrong)? For comparison, the same scenario (exactly the same code, linkage, etc.) built for Mac OS X works as required regardless of what thread ___setup() is called from initially. Thanks.

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Fwd: Puzzlement (different behavior of compiled code)
by David Rush 10 Jui '12

10 Jui '12

forgot to include the list in the correspondence. This is the (happy) outcome... ---------- Forwarded message ---------- From: David Rush <kumoyuki(a)gmail.com> Date: 10 June 2012 15:44 Subject: Re: [gambit-list] Puzzlement (different behavior of compiled code) To: Mikael <mikael.rcv(a)gmail.com> Ta much Mikael! It turns out that the -:s flag to gsc is the culprit. I had been using that flag out of habit to get the syntax-case expander - apparently it also interferes with recognizing keywords. I think i need "-:S" instead, which i guess has been added since I last update my Gambit makefiles (don't ask - it's been a while) thanks again - d On 10 June 2012 15:27, David Rush <kumoyuki(a)gmail.com> wrote: > On 10 June 2012 14:31, Mikael <mikael.rcv(a)gmail.com> wrote: >> >> Uh this is funny: >> >> (open-output-file '(|path:| "test.flog" |create:| maybe |append:| #t)) >> >> look there, there's |:s around the keywords. This means they're *not* >> actually keywords but *symbols* that kind of look like keywords. > > That is interesting. I have no idea why, as I said it's the same code > in both cases (code was included in the tail of the OP) > >> Tried to reproduce your error on 4.6.2: >> >> $ cat a.scm >> (write (cons abcde: 123)) >> $ gsi a.scm >> (abcde: . 123)$ gsc -exe a.scm >> $ ./a >> (abcde: . 123) > > I wonder if mine is a case that occurs because the code renames cons > (in an attempt to avoid variable capture while expanding macros) so > that instead of cons the var referenced is actually _cons_23 - leading > to compiler confusion about special cases. > >> Do you compile this code just with gsc filename.scm or (compile-file >> "filename.scm") or do you have some preprocessor on it? > > from the original message: > > ----------------------------------------------------------------------- > drr@dibbuk$ make target=gambit test/bug.gambit > gsc -:s -link test/bug.Gambit > gcc -I/home/drr/include test/bug.c test/bug_.c -o test/bug.gambit \ > -L/home/drr/lib -lgambc -lm -lutil -ldl > ------------------------------------------------------------------------ > > which is something of a habit i have with Gambit going back many years > in order to actually insert a lot of gcc optimization flags (*not* > included in this test case) > >> Do you see any other reasons for why this occured? > > just what I suggested above. It gives me something to try anyway. > > d > -- > GPG Public key at http://cyber-rush.org/drr/gpg-public-key.txt -- GPG Public key at http://cyber-rush.org/drr/gpg-public-key.txt -- GPG Public key at http://cyber-rush.org/drr/gpg-public-key.txt

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Puzzlement (different behavior of compiled code)
by David Rush 10 Jui '12

10 Jui '12

With Gambit 4.6.6, I am seeing decidedly different behavior for open-output-file between code compiled with gsc/gcc to run as a standalone executable and that same code compiled with gsc to run under gsi. The source code follows the body of the message, but the error from the standalone run tells the whole story, really. Specifically: ---------------------------------------------------------------------- drr@dibbuk$ make target=gambit test/bug.gambit gsc -:s -link test/bug.Gambit gcc -I/home/drr/include test/bug.c test/bug_.c -o test/bug.gambit \ -L/home/drr/lib -lgambc -lm -lutil -ldl drr@dibbuk$ test/bug.gambit *** ERROR IN flog-file -- (Argument 1) STRING or port settings expected (open-output-file '(|path:| "test.flog" |create:| maybe |append:| #t)) drr@dibbuk$ gsc test/bug.Gambit drr@dibbuk$ gsi Gambit v4.6.6 > (load "test/bug") "/home/drr/git/heureka/framework/test/bug.o2" > (main (vector "this is a test")) > (exit) drr@dibbuk$ cat test.flog this is a test this is a test ------------------------------------------------------------------------ Now the repeated lines in test.flog are expected from the gsi case because the code is effectively run twice, once upon load and once manually (as will be seen from the source below). So what is going on with the standalone execution? I am very puzzled. the source code for bug.Gambit. This is the output of a preprocessor, so it looks a little strange, but it is really very straightforward. ------------------------------------------------------------------ (define _cons_23 cons) (define *flog-use-current-output-port* #f) (define *flog-use-current-error-port* #f) (define flog-file (lambda (_file-name_38 _s_39) ((lambda (_f_40) (begin (display _s_39 _f_40) (newline _f_40) (if *flog-use-current-output-port* (display _s_39 (current-output-port))) (if *flog-use-current-error-port* (display _s_39 (current-error-port))) (close-output-port _f_40))) (open-output-file (_cons_23 (quote path:) (_cons_23 _file-name_38 (quote (create: maybe append: #t)))))))) (define main (lambda (_argv_38) (begin (flog-file "test.flog" "this is a test") ))) (main (command-line))

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Re: [gambit-list] Puzzlement (different behavior of compiled code)
by Mikael 10 Jui '12

10 Jui '12

I cannot see any possibility that the compiler would confuse things in such a way that instead of doing (string->keyword "path") it does (string->symbol "path:") . Can you please reduce this bug to its simplest form and tell the outcome here? This ought to shed light over what's wrong. Brgds 2012/6/10 David Rush <kumoyuki(a)gmail.com> > On 10 June 2012 14:31, Mikael <mikael.rcv(a)gmail.com> wrote: > > > > Uh this is funny: > > > > (open-output-file '(|path:| "test.flog" |create:| maybe |append:| #t)) > > > > look there, there's |:s around the keywords. This means they're *not* > > actually keywords but *symbols* that kind of look like keywords. > > That is interesting. I have no idea why, as I said it's the same code > in both cases (code was included in the tail of the OP) > > > Tried to reproduce your error on 4.6.2: > > > > $ cat a.scm > > (write (cons abcde: 123)) > > $ gsi a.scm > > (abcde: . 123)$ gsc -exe a.scm > > $ ./a > > (abcde: . 123) > > I wonder if mine is a case that occurs because the code renames cons > (in an attempt to avoid variable capture while expanding macros) so > that instead of cons the var referenced is actually _cons_23 - leading > to compiler confusion about special cases. > > > Do you compile this code just with gsc filename.scm or (compile-file > > "filename.scm") or do you have some preprocessor on it? > > from the original message: > > ----------------------------------------------------------------------- > drr@dibbuk$ make target=gambit test/bug.gambit > gsc -:s -link test/bug.Gambit > gcc -I/home/drr/include test/bug.c test/bug_.c -o test/bug.gambit \ > -L/home/drr/lib -lgambc -lm -lutil -ldl > ------------------------------------------------------------------------ > > which is something of a habit i have with Gambit going back many years > in order to actually insert a lot of gcc optimization flags (*not* > included in this test case) > > > Do you see any other reasons for why this occured? > > just what I suggested above. It gives me something to try anyway. > > d > -- > GPG Public key at http://cyber-rush.org/drr/gpg-public-key.txt >

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Gambit on Android
by Steve Graham 10 Jui '12

10 Jui '12

I understand that Android apps are typically written in Java. How then is Gambit able to run on that platform? If it is possible to write GUI apps for the Android using Gambit, are there any pointers on how to get started? Thanks, Steve

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Re: [gambit-list] What about Gambit did you always want to get a good understanding of? (design of any aspect, compiler & VM)
by Estevo 09 Jui '12

09 Jui '12

Thanks to you and Marc for offering your time and knowledge! (Some thoughts follow after the quote.) > Date: Sat, 9 Jun 2012 00:57:11 +0300 > From: Mikael <mikael.rcv(a)gmail.com> > Subject: [gambit-list] What about Gambit did you always want to get a > good understanding of? (design of any aspect, compiler & VM) > To: gambit-list(a)iro.umontreal.ca > Message-ID: > <CACbx-M8N+S7KMYe61Z+X6svuZMd1RNUct8ETuKtXVeJLePo5pA(a)mail.gmail.com> > Content-Type: text/plain; charset="iso-8859-1" > > (let's recontextualize the q from the previous email to a separate thread:) > > > Anyone please feel free to suggest questions or angles on subjects that > should be addressed in this document, so that these will be covered too. > > So basically, what about Gambit have you always wanted to get a good > understanding of (and which is not quite obvious from looking at Gambit's > sourcecode), and how would you formulate the questions that would take you > to getting this understanding? This is probably lazy and not very helpful of me, but my reply to that question would be Overview/Start Here. A generalistic article that listed the various aspects of Gambit, and for each of such aspects: - links to papers that may be helpful in understanding the implementation (the email you sent earlier would make an excellent starting point in this regard -- thanks for collecting those!), and - links to the github pages of the most relevant files in the source code. The latter could be pegged to some specific version to make sure docs and code don't fall out of sync. I imagine most of the time it will not be critical to point to the current head. Regards, Estevo.

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What about Gambit did you always want to get a good understanding of? (design of any aspect, compiler & VM)
by Mikael 08 Jui '12

08 Jui '12

(let's recontextualize the q from the previous email to a separate thread:) Anyone please feel free to suggest questions or angles on subjects that should be addressed in this document, so that these will be covered too. So basically, what about Gambit have you always wanted to get a good understanding of (and which is not quite obvious from looking at Gambit's sourcecode), and how would you formulate the questions that would take you to getting this understanding?

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4.6.6 or 4.2.8
by Steve Graham 08 Jui '12

08 Jui '12

Just downloaded and built the latest version. Verbiage in make indicated it was 4.6.6. However, when I fired up gsi and gsc, they both said 4.2.8. I am running on an x64 Linux system. Steve

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