Re: [Haskell-cafe] Printing call site for partial functions

On Wed, Apr 25, 2012 at 7:28 PM, Ozgur Akgun wrote:

Hi,

On 25 April 2012 16:36, Michael Snoyman wrote:

...

   Prelude.head: empty list

Recent versions of GHC actually generate a very helpful stack trace, if the program is compiled with profiling turned on and run with -xc.

See: http://community.haskell.org/~simonmar/slides/HIW11.pdf (Ironically titled "Prelude.head: empty list")

HTH, Ozgur

I certainly think that stack traces are going to be a powerful debugging tool, and I'm looking forward to using them. But I think this feature would be useful in and of itself. I'm presuming it won't be the default to have stack traces turned on due to performance overhead (is that a faulty assumption?). This feature would be available for all builds and give you a very high amount of useful information- though not quite as much as a stack trace- without any (serious) performance impact. Michael