Hello Wouter.
I've had a go at the paper linked and perused other references found
with Google. Unfortunately, such sophisticated use of the type system
is pretty far out of my normal problem domain and I can't see how to
apply the techniques presented to my motivating example. Would you be
so kind as to elaborate?
Thank you,
Brian
On Mon, Jul 27, 2009 at 2:37 AM, Wouter Swierstra
Hi Brian,
If I understand you correctly, you've run into the "Expression Problem". Phil Wadler posed the problem in a widely-cited e-mail, formulating it much more clearly than I ever could:
http://homepages.inf.ed.ac.uk/wadler/papers/expression/expression.txt
There are lots of ways to tackle this problem in Haskell - just google "Expression Problem Haskell". My (completely biased) personal favourite is:
http://www.cse.chalmers.se/~wouter/Publications/DataTypesALaCarte.pdf
Hope this helps,
Wouter