sum [] = 0 sum (x:xs) = x + sum xs
typing
sum [1,2,3]
should yield this trace
sum [1,2,3] 1 + sum [2,3] 1 + 2 + sum [3] 1 + 2 + 3 + sum [] 1 + 2 + 3 + 0 1 + 2 + 3 1 + 5 6
I know there are advanced tools like Hat, but (unless I'm missing something) they don't yield anything as naive as the above, and it's naive users I'm trying to help here. -- P
PS. Google search on "Haskell trace" yields lots on Hat, plus the following.
The Mystery of Brigadier General Harry L. Haskell
... we have developed a short biography of General Haskell and been able to trace the
locations where he lived, and, possibly, how the medal came into my family. ...
family.phelpsinc.com/branches/haskell/ - 28k - Cached - Similar pages
Philip Wadler, Professor of Theoretical Computer Science School of Informatics, University of Edinburgh JCMB, Mayfield Road, Edinburgh EH9 3JZ SCOTLAND +44 131 650 5174 http://homepages.inf.ed.ac.uk/wadler/ _______________________________________________ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell