Re: [Scheme-reports] [r6rs-discuss] Scheme pattern matching: the case for (case)

[Per Bothner <per@x>]

On 12/22/2010 12:15 PM, John Cowan wrote:
> Peter Kourzanov scripsit:
>
>> (define eqv? equal?)
>> (newline)
>> (write (case "asd" (("asd") #t)))
>> (newline)
>>
>> You'll find Tinyscheme, Minischeme, MIT, Scheme48/SCSH
>> included in your list. Ypsilon and Stalin exhibit this
>> behaviour for strings, but not for more structured data
>> like vectors.
>
> Chicken, Bigloo, Kawa, SISC, Chibi, STklos, and Scheme 9 also have this
> problem; Racket, Gauche, Gambit, Guile, Chez, SCM, Larceny, Mosh, and
> SSCM do not; Ikarus won't let you rebind EQV?.

"Problem" is a strange word in this context - that eqv? was defined as 
equal? is
irrelevant to what is happening (at least for Kawa).  The reason the result
is #t is that (as you mention elsewhere):

   implementations are free to make literal strings eqv? if they have 
the same content
-- 
	--Per Bothner
per@x   http://per.bothner.com/

_______________________________________________
Scheme-reports mailing list
Scheme-reports@x
http://lists.scheme-reports.org/cgi-bin/mailman/listinfo/scheme-reports