[r6rs-discuss] [Formal] Requirement to detect circular lists

From: AndrevanTonder <andre>
Date: Wed Oct 4 08:41:35 2006

Sorry to be a pest, but I am wondering why introduce
the whole machinery of plausible lists at all?

If I understand correctly, the intended semantics
of (map f x) can be stated much more simply as:

   - Implementations of map are required to check whether
     x is a list before the first application
     of f. If x is not a list, an exception must
     be raised.

This check is decidable (ignoring concurrency, as one
should, since r6rs Scheme does not have concurrency).
No extra section is needed to describe this...

Cheers
Andre
Received on Wed Oct 04 2006 - 08:38:47 UTC