I asked more or less the same question in august 2012.
as I have gained more experience with Haskell, the problem has become less
important and I think it will be the same with you. But there is a better
solution than Maybe and others, haskell can give you a stack trace if you
compile with profiling enabled:
http://marc.info/?t=135220245600002&r=1&w=4
I now make sure to compile all my libraries with profiling enabled, just in
case I may need it...
emmanuel
On Sun, Mar 31, 2013 at 5:42 PM, Nathan Hüsken
Hey,
I have written a program which, when executed produces:
Main: Prelude.head: empty list
Now, I can go through my program and replace all "head" with
(\a -> trace ("<line-nr>: length=" ++ (show (length a))) a)
Actually, I already did that, and by this I found the error. But I wonder if there would have been an easier way? Has anyone any debug advice how I could find out which call to "head" causes this without so much typing work?
Thanks! Nathan
______________________________**_________________ Beginners mailing list Beginners@haskell.org http://www.haskell.org/**mailman/listinfo/beginnershttp://www.haskell.org/mailman/listinfo/beginners