On Wed, Jun 25, 2008 at 02:24:57PM -0400, Brent Yorgey wrote: > On Wed, Jun 25, 2008 at 07:50:08PM +0200, Niels Aan de Brugh wrote: > > On Wed, 2008-06-25 at 16:50 +0200, Conal Elliott wrote: > > > I have a foggy memory that early ML had only binary pairing, nesting > > > for n-tuples. Can anyone confirm this memory. If so, does anyone > > > remember the rationale for going to n-tuples? Performance, perhaps? > > > > ???What is the difference between a list build up of Cons and a "tuple" > > made out of pairs? I think the latter wouldn't really add anything new. > > The difference is that all the elements of a list must be the same > type, whereas nested tuples could have elements of any type. For > example, > > (True, (6, 'c')) :: (Bool, (Int, Char)) > > and there is no corresponding three-element list. However, you're > right in noting the similarity between lists and nested tuples -- in > fact, this is exactly how lists are implemented in lisp (which is > where we get the tern 'cons').
The other difference is that nested tuples have the number of elements specified in the type, while lists do not. -- David Roundy Department of Physics Oregon State University _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe