[Jscheme-user] Re: JScheme questions

[Alan D. <ado...@cs...>]

On Mon, Jul 19, 2004 at 11:24:26AM -0400, Ken Anderson wrote:
> Tim, i'd like to propose this as a new definition of eqv?
> (define (atomicClass? c)
>   (or (eq? c Boolean.class)
>       (eq? c Byte.class)
>       (eq? c Short.class)
>       (eq? c Integer.class)
>       (eq? c Long.class)
>       (eq? c Float.class)
>       (eq? c Double.class)
>       (eq? c Symbol.class)))

(and don't forget Character.class)


> (define (eqv? x y)
>   (or (eqv? x y)
>       (let ((c (.getClass x)))
>         (and (atomicClass? c)
>              (eq? c (.getClass y))
>              (.equals x y)))))

I think there's a typo for 'eq?' on line 2.

What about the #null value?  This would (unfortunately) require extra
cases because (.getClass #null) fails.


> You're using case incorrectly.  Your code expands into:
> (let ((temp var (String. "foo")))
>   (cond ((member temp var '(String. "foo")) #t)
>         (else #f)))

Right.  I'm relatively new to Scheme ;-)


Thanks for your help!  (Sorry if my comments above are pedantic.)
I'll subscribe to the list.


cheers
alan