When I was writing
http://www.vex.net/~trebla/haskell/crossroad.xhtml
I wanted to write: branching on predicates and then using selectors is
less efficient than pattern matching, since selectors repeat the tests
already done by predicates.
It is only ethical to verify this claim before
Note that, unfortunately, GHC's exhaustiveness checker is *not* good
enough to figure out that your predicates are covering. :o) Perhaps
there is an improvement to be had here.
Edward
Excerpts from Albert Y. C. Lai's message of Mon Apr 22 00:51:46 -0700 2013:
When I was writing
