[plt-scheme] Conditional bind then do something

From: Jens Axel Soegaard (jensaxel at soegaard.net)
Date: Tue Feb 24 16:27:59 EST 2009

y1wm6lg02 at sneakemail.com wrote:
> Just posted to comp.lang.scheme...

Wait at least a day before making a duplicate post.

Why? Well, if person A answers on this list, there
is no reason why person B, should spend his time
answering on c.l.scheme.

> Hi,  I'd like a let... binding to extend beyond the let.  The idea
> is to bind the variables to one thing or another, then pass them to
> some subsequent procedure, without using set!, etc.
> Something like the following python
> def some_function(arg):
>    if some_test(arg):
>       var1=123
>       var2=456
>    else:
>       var1="xyz"
>       var2="abc"
>    do_blaaa(var1, var2)

How about this:

(define (some-function arg)
   (apply do-blaaa
          (if (some-test arg)
              (list 123 456)
              (list "xyz" "abc")))



(define (some-function arg)
    (define-values (arg1 arg2) (if (some-test arg)
                                   (values 123 456)
                                   (values "xyz" "abc"))
    (do-blaaa arg1 arg2))

Jens Axel Søgaard

Posted on the users mailing list.