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Programming language shootout benchmark programs
by Bradley Lucier 23 Fév '08

23 Fév '08

Motivated by a blog for the GHC Haskell compiler, I've added programs for the Computer Language Benchmarks Game http://shootout.alioth.debian.org/ to the Gambit Wiki, starting at a new benchmarks page here: http://dynamo.iro.umontreal.ca/~gambit/wiki/index.php/Benchmarks Knock yourself dead improving these if you like, or on filling in the gaps; I plan to submit something for these benchmarks after 4.2.3 is released. (I'm waiting because there are several bug fixes in the compiler that speed up some of these benchmarks considerably.) Brad

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read-subu8vector
by Guillaume Cartier 23 Fév '08

23 Fév '08

In my web-server when I receive a request, the code to parse that request that is very natural goes something like : - read-line until received an empty line to read the headers - read-subu8vector to read the body that could be anything Problem is that the doc states that read-subu8vector should *not* be used after character input operations have been done on the port because otherwise the character-stream and byte-stream may be out of sync due to the port buffering. Is there any work around this limitation? (of course it is possible to modify the code not to do any character input operations but it becomes less elegant) Thanks, Guillaume Cartier

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read-subu8vector
by Jeremie Lasalle Ratelle 22 Fév '08

22 Fév '08

> (define vect (make-u8vector 3)) > (call-with-input-string "string" (lambda (pt) (read-subu8vector vect 0 2 pt))) *** ERROR IN call-with-input-string -- Input port character buffer is not empty (read-subu8vector '#u8(0 0 0) 0 1 '#<input-port #2 (string)>) read-subu8vector calls macro-lock-and-check-input-port-character-buffer-empty I guess it's a bug since I don't see what would be the use. Or enlighten me...

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Integer infinity?
by David St-Hilaire 22 Fév '08

22 Fév '08

Hi gambit-list! I'd like to know how can I compare an exact number with the +/- infinity value... I've found that there is +inf.0 available for inexact numbers, but a simple (exact->inexact +inf.0) does not seem to work :(. Thank you! ^_^ David

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Termite problems
by Nicholas Walton 20 Fév '08

20 Fév '08

Hi, I've just started working with Termite to distribute the processing for a large data mining system over a multi core CPU and I seem to be hitting a few problems for which any advice is welcome. Small scale examples seem to work well but once I scale up I hit problems. I'm running on a 1Gig Mac using OS X 10.4 with the latest distribution of Gambit and the current tarball from the Termite site together with the slib library. At first I built a two process client server example but it hung. The problem turned out to be the array.scm file in the slib distribution redefining the equal? procedure. Once the redefinition was removed all worked well. So long as I used tags and not pids to identify one remote process to another. The pid returned by remote-spawn is not the same as that returned by the process calling (self). I then moved on to trying a parallel version of map, akin to that given at http://theschemeway.blogspot.com/2007/06/parallel-map-with-termite.html . That worked fine for small simple examples but when I threw in a larger example, evaluating forty instances of a k-means cluster procedure in parallel in one process, it consistently dumps core but not in any predictable manner. All forty threads kick off fine but while some succeed others fail catastrophically and at no particular point resulting in Gambit dumping core. I've run the code using map and all was well, and the code has nothing in it which seems likely to cause the problem. I've run the code both compiled and fully interpreted and the behavior is the same. First is there any changes to the Gambit build which might help identifying where the fault is occurring? Secondly are there known problems with Termite especially when spawning moderately large processes.? Many Thanks Nick Walton

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Questions about tables.
by Bradley Lucier 19 Fév '08

19 Fév '08

Marc: I have some questions about tables. 1. Can there be a function like (table-update! table key (lambda (#!optional (value default-value)) <whatever>)) instead of using (table-set! table key ((lambda (value) <whatever>) (table-ref table key default-value))) It would seem to avoid one table lookup for the key. 2. I presume that the table can get messed up if the keys are mutable and you change the key (like a string) after it has been used to index the table. Or is it possible to tell the table to copy any keys that are not in the table as they are entered into the table? Brad

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Namespaces
by jadamson＠partners.org 13 Fév '08

13 Fév '08

Hello Gambitious Schemers, I've read the Wiki Namespaces page and I'm still trying to figure out how to incorporate the information. Here's my situation: * I have copied ~~/syntax-case.scm to ~~/gambcext.scm since I want to use some syntax-rules macros * I compile a file that "include"s all the relevant files and then includes a funny message: ;;;test.ss (include "c-header.ss") (include "scheme-header.ss") (include "gsl_structures.ss") (include "gsl_lalgebra.ss") (include "gsl_wrapper.ss") (include "f64matrix.ss") (include "life-table.ss") ;;includes ;;(define-structure life-table gens m p a) (define C (make-f64matrix 2 2 (f64vector 8.67 53.09 3.14 2.17))) (define C-gsl (make-gsl-matrix 2 2 (f64matrix-data C))) (define C->gsl (f64matrix->gsl-matrix* C)) (define vec2 (f64vector 1.0 1.0)) (define tbl (make-life-table '(1 2) '(5 10 20) '(0.5 0.75 0.9) '(0.5 0.5 0.5))) (display "Good evening, Dave. Everything's running smoothly, and you?") (newline) I compile this with: # a rudimentary Makefile for Gambit targets LDOPTS="-g -L/usr/lib/gsl -lgslcblas -lgsl" CCOPTS="-I/usr/include" GSCOPTS=-keep-c -debug -track-scheme -warnings -expansion libs = gsl_lalgebra.ss gsl_wrapper.ss f64matrix.ss test: gsc $(GSCOPTS) -ld-options $(LDOPTS) -cc-options $(CCOPTS) test.ss Everything compiles just fine. * I "run-scheme" in Emacs, and then the action happens: Gambit v4.2.0 > (load "test") Good evening, Dave. Everything's running smoothly, and you? "/home/joel/lisp/scm/population/libgenx/test.o11" > ##make-life-table *** ERROR IN (stdin)(a)2.1 -- Unbound variable: ##make-life-table 1> ,t > make-life-table *** ERROR IN (stdin)(a)4.1 -- Unbound variable: sc#make-life-table 1> ,t > sc#make-life-table *** ERROR IN (stdin)(a)6.1 -- Unbound variable: sc#make-life-table 1> * So, what's going on here? What namespace is my structure attached to? Do I need to define namespaces in my files to be able to access these things from the REPL (and in future code)? * The wiki page mentions something about the namespace functions not being supported in the future. What is the status of the namespace mechanism supported or not? Will it be in the future? It seems like I need to use it if I am going to use syntax-case, or will that change too? Thanks, Joel -- Joel J. Adamson Biostatistician Pediatric Psychopharmacology Research Unit Massachusetts General Hospital Boston, MA 02114 (617) 643-1432 (303) 880-3109 The information transmitted in this electronic communication is intended only for the person or entity to whom it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of or taking of any action in reliance upon this information by persons or entities other than the intended recipient is prohibited. If you received this information in error, please contact the Compliance HelpLine at 800-856-1983 and properly dispose of this information.

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bugzilla is stale
by Bradley Lucier 13 Fév '08

13 Fév '08

Marc: I just went through gambit's list of "bugs" in bugzilla and closed a bunch of them since it appears that they've been fixed since the bugs were first reported. I think it would be good if bugzilla could be the place where bugs are introduced and discussed, where *patches related to those bugs are posted* (or at least a link made to the mercurial patch that fixes them), where bugs are closed, etc. Having a stale bugzilla doesn't help gambit development. (And it would be better if you personally were to submit comments on bugzilla as "feeley" rather than the omniscient and omnipotent "gambit", so that people would know who the man is behind the curtain that is talking to them.) Brad

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Embedding a REPL in an executable
by Neil Baylis 12 Fév '08

12 Fév '08

I'm building an executable that links with an object file that controls a machine via the USB bus. I have this working OK by linking everything into an executable. But that means I must recompile every time I make a change to my scheme code. Instead, I'd like to be able to load the scheme code at runtime. Originally I wanted to compile my c code into a library so that I could load it with gsi. However i was unable to get that to work. Poking around in the examples, I found (##repl-debug-main), so I put that at the end of my c-api .scm file. This works well. When I run the executable, I get a repl, and can then load further scheme files as needed. Is this the recommended way to embed a Gambit repl in a c program? Where can I find this ##repl-debug-main documented? What's the significance of the ## character? Is there a way to pass startup arguments to this repl? Thanks, Neil Baylis -- http://www.pixpopuli.com

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Segmentation fault from simple (infinite) loop
by Ryan Mulligan 11 Fév '08

11 Fév '08

rmulliga@rtmlap ~/gambc-v4_2_1> bin/gsi-script Gambit v4.2.1 > (define (loopy x) (println x)(loopy (+ 1 x))) > (define (loopy x) (print x ) (print " ")(loopy (+ 1 x))) > (loopy 1) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978fish: Job 1, "bin/gsi-script " terminated by signal SIGSEGV (Address boundary error) Why am I getting a seg fault? rm

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