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
_______________________________________________
Haskell-Cafe mailing list
[email protected]
http://www.haskell.org/mailman/listinfo/haskell-cafe
