On 2008 Dec 1, at 8:28, Andrew Wagner wrote:

Hm, I've been thinking about this this morning as I've gone about my commute. I could indeed imagine a class like the following that had multiple implementations like you're talking about:

One can indeed --- but it turns out to be even more general than just trees. Go look at the Foldable and Traversable classes.

brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery@kf8nh.com

system administrator [openafs,heimdal,too many hats] allbery@ece.cmu.edu

electrical and computer engineering, carnegie mellon university KF8NH