Scheme Sucks

3. Personally, I don't like names formed like this x->y to indicate a conversion because this order makes it difficult to understand compositions; for example, ( y->z(x->y... ) ) is less straightforward than (z<-y(y<-x... ) ). In contrast, x->y is much easier to read than y<-x. You can see here one of the many difficulties that language designers come up against.

>>9
(define (a->x a)
  (cond ((y? a) (y->x a))
        ((z? a) (z->x a))
        (else (error ...))))

(define (a->y a)
  (cond ((x? a) (x->y a))
        ((z? a) (z->y a))
        (else (error ...))))

(define (a->z a)
  (cond ((x? a) (x->z a))
        ((y? a) (y->z a))
        (else (error ...))))

Now read SICP or scrub another fucking toilet you mental midget.