On 4/8/08, Graham Fawcett <[EMAIL PROTECTED]> wrote: > On Mon, Apr 7, 2008 at 3:24 PM, Alex Rozenshteyn <[EMAIL PROTECTED]> > > 2) Is the interpreter supposed to freeze if length is passed a cyclic > list?
> Yes, it's correct. See length and length+ in SRFI-1: > http://srfi.schemers.org/srfi-1/srfi-1.html#Miscellaneous > length+ will give you sane behaviour with cyclic lists. For background, you can find some information on the design of length+ at: http://srfi.schemers.org/srfi-1/mail-archive/msg00038.html Of course, length+ returns #f for circular lists. If you want a count of "distinct elements", a procedure using the tortoise and hare algorithm is available in the same thread: http://srfi.schemers.org/srfi-1/mail-archive/msg00096.html The question of whether "how many elements are in a circular list" is well-defined is also discussed. Jim _______________________________________________ Chicken-users mailing list Chicken-users@nongnu.org http://lists.nongnu.org/mailman/listinfo/chicken-users
