[Haskell-cafe] Best way to find an "undefined" error?

[Denis Bueno]

On Thu, Feb 14, 2008 at 2:55 PM, Don Stewart <dons at galois.com> wrote:
>  You can use the profiler to get a stack trace, or use the new
>  GHCi debugger to step backwards from the exception to the source.
>
>  I wrote a bit of a tutorial for this here:
>
>  http://cgi.cse.unsw.edu.au/~dons/blog/2007/11/14#no-exceptions

Section 6.3 of http://haskell.org/haskellwiki/Debugging also is
relevant for using ghcu to step backward ... perhaps the section label
is misleading, though.  Feel free to modify as needed if you find the
ghci stepper lets you find the problem

-- 
 Denis