John Cowan <cowan@x> writes:Thanks John. Guile should be added to the above list though.
> Okay, the details are at ComplexRepresentations now. Racket, Kawa, Chez,
> Vicare, Larceny, Ypsilon, !IronScheme, Spark support (imag-part 2.0) => 0
> even though they don't support mixed-exactness complex numbers.
Interesting. Chibi 0.6.1 (the latest release) returns (#f #t #t) on my
>> >> Another test that would be worthwhile is this:
>> >> (list (eqv? +0.0 -0.0)
>> >> (eqv? (make-rectangular +0.0 1.0)
>> >> (make-rectangular -0.0 1.0))
>> >> (eqv? (make-rectangular 1.0 +0.0)
>> >> (make-rectangular 1.0 -0.0))
>> >> I wouldn't be surprised if some Schemes distinguish signed zeroes in the
>> >> real part but not in the imaginary part. If an implementation discards
>> >> inexact zero imaginary parts, then it probably discards the sign as well
>> >> as the exactness.
> The results here weren't interesting: they were all either (#t #t #t)
> or (#f #f #f), or throwing an error on undefined `make-rectangular`,
> with the sole exception of Vicare, which returns (#t #f #f).
system. What does it return on yours?
Also, Ikarus from Debian Wheezy returns (#f #t #t), which means that all
three test results are inverted compared with Vicare. I find this
surprising. Are you sure you copied the result correctly?
Anyway, these tests uncovered bugs in Vicare, Ikarus, and Chibi, and the
absence of that bug in the other Schemes you tested, so that's useful
Good point. Here's an improved version which also adds three more
> However, this version does not properly defend against systems which
> interpret `-0.0` as just another spelling of 0.0 even though they
> support negative zero internally.
useful tests. If you prefer, you could send me the raw data, and I'd
be glad to summarize the results.
(let* ((pos-zero (do ((x +1.0 (/ x 2))) ((zero? x) x)))
(neg-zero (do ((x -1.0 (/ x 2))) ((zero? x) x))))
(list (eqv? pos-zero neg-zero)
(eqv? (make-rectangular pos-zero 1.0)
(make-rectangular neg-zero 1.0))
(eqv? (make-rectangular 1.0 pos-zero)
(make-rectangular 1.0 neg-zero))
(eqv? 1.0 (make-rectangular 1.0 pos-zero))
(eqv? 1.0 (make-rectangular 1.0 neg-zero))
(eqv? 1.0 (make-rectangular 1.0 0))))
I get the following results with my small selection of Schemes:
(#f #f #f #f #f #t) [R6RS] Guile, Racket, Gambit
(#t #t #t #t #t #t) [R5RS] Scheme48, Gauche, SCM, Chicken w/ numbers egg
(#f #t #t #f #f #t) [buggy] Ikarus, Chibi
_______________________________________________ Scheme-reports mailing list Scheme-reports@x http://lists.scheme-reports.org/cgi-bin/mailman/listinfo/scheme-reports