John Meacham writes:
On Thu, Mar 02, 2006 at 09:13:11PM +0000, Adrian Hey wrote:
I think what we should be aiming for in the long term is automatically derived Generalised Tries (as discussed recently).
Would it be possible to mock up an implementation of this using Data.Generics by chance? so we can use a generalized tree for anything in Data and Ord? I find the idea of a derived generalized trie quite intriguing. would associated types be the best way to express such a thing (so you can use 'Trie a' everywhere as a type rather than some complicated class predicate).
A while back, I put together an implementation of generic tries based on
Ralf Hinze's "Generics for the Masses". This particular technique allows
you to write M functions for N types with M+N instances, instead of M*N.
It's now on-line at http://www.eyrie.org/~zednenem/2006/gentrie/. It's
a darcs repository, so "darcs get" will work. There are two versions
(corresponding to associated type synonyms and associated data types),
plus an alternate interface that hides the map's type.
--
David Menendez