Re: [stack] sweetening concatenative syntax

On Mar 19, 2008, at 3:06 AM, John Nowak wrote:

> Here's another version of the above with a syntax more suited to a
> concatenative language:
>
> quad a b c = p n
>    where d = b 4 a c * * -
>          r = d 0 >= [d sqrt] ["quad: sqrt of negative" error] if
>          x = 2 a *
>          p = b r - x /
>          n = b r + x /

Or in a manner requiring less heroics for people with more taste and  
sophisticated structural editors:

   (define (quad a b c)
     (let ((d b 4 a c * * -)
           (r d 0 >= [d sqrt] ["quad: sqrt of negative" error] if)
           (x 2 a *)
           (p b r - x /)
           (n b r + x /))
       p n))

Unlike Manfred's original example, these return 'p' and 'n' on the  
stack directly. '[...]' is just sugar for '(lambda () ...)', where  
'lambda' expands to point-free code if variables are introduced.

Yes, I want a typed Scheme where functions can easily produce (and  
subsequently consume) multiple values. Is that so wrong?

- John