[gambit-list] Gambit-C 4.0 beta 14

Marc Feeley feeley at iro.umontreal.ca
Fri Jul 15 02:41:26 EDT 2005

A new beta of Gambit-C 4.0 is now available in source form at this


Here's what's new:

- Binary serialization.  The procedures object->u8vector and
   u8vector->object implement binary serialization and deserialization.
   The representation used is 2 to 3 times more compact than
   text serialization.  Moreover, these procedures are implemented
   more efficiently, with tables, which makes binary serialization
   and deserialization two orders of magnitude faster than text

- Better conformance to the draft "R6RS Unicode data" SRFI.  The range
   of the character type has been extended to #x10FFFF.  Each character
   in a string now occupies 4 bytes of memory.  The size of characters
   can be changed by redefining the macro ___MAX_CHR in gambit.h and
   recompiling the system.  ___MAX_CHR can be 0xFF (1 byte per  
   0xFFFF (2 bytes per character), or 0x10FFFF (4 bytes per character).
   The syntax for characters, quoted strings and "here strings" proposed
   in the SRFI have been implemented, and the old #\#x1234 syntax for
   characters has been removed (you should now use #\u1234 instead).

- Improvements to the Gambit compiler.  A minor modification to the
   code generator has improved the register allocation.  The inlining
   of arithmetic procedures (+, -, *, ...) has been improved.   For
   example, the program

   (define (triple x)
     (* x 3))

   (define (make-multiplier x)
     (lambda (y)
       (* x y)))

   is expanded to

   (define triple
     (lambda (x)
       (if (and (##eq? * '#<procedure #2 *>) (##fixnum? x))
           (let ((temp (##fixnum.*? x 3))) (if temp temp (* x 3)))
           (* x 3))))

   (define make-multiplier
     (lambda (x)
       (lambda (y)
         (if (and (##eq? * '#<procedure #2 *>) (and (##fixnum? y)  
(##fixnum? x)))
             (if (##fixnum.= y 0)
                 (let ((temp (if (##fixnum.= y -1)
                                 (##fixnum.-? x)
                                 (##fixnum.*? x y))))
                   (if temp temp (* x y))))
             (* x y)))))

- Testing tables for equality.  Tables can be compared for equality
   using the equal? procedure.  Two tables X and Y are considered
   equal by equal? when they have the same weakness attributes, the same
   key comparison procedure, the same hashing procedure, the same  
   and for all the keys k in X, (equal? (table-ref X k) (table-ref Y  

- Compiled scripts now behave the same as interpreted scripts.  The
   "main" procedure will be called automatically, the language will be
   set according to the first line of the script, and the value returned
   by the procedure "command-line" will be the list of command line
   arguments after the script filename.  Scripts can also be compiled
   to an executable program.

- Process port fixes.  Several problems with process ports have been  
   in particular when pseudo-terminal: is #t.  This makes it easy for
   a Scheme program to interact with programs that were designed to be
   used interactively.  Here is an example:

   > (define p (open-process
                 (list path: "/sw/bin/emacs"
                       arguments: '("-nw")
                       pseudo-terminal: #t)))
   > (read-line p)
F1  ..."

- Documentation checking.  A script now checks that the documentation
   is consistent with the behavior of the system.  This has helped
   uncover many inconsistencies.  Unfortunately only a few of the
   inconsistencies have been fixed at this point.


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