On 08 November 2005 23:53, John Meacham wrote:
On Tue, Nov 08, 2005 at 11:12:09AM -0000, Simon Marlow wrote:
One idea that occurred to us recently is this: GHCi could provide a simplified version of the cost-centre-stack machinery *all the time*, giving you a proper backtrace for any exception, at least for the parts of the call stack that are interpreted. We don't care about the cost too much - interpreted code is a lot slower than compiled already, and it would only be a small constant factor. I think this would be a huge win for debuggability. And a nice project for anyone who wants to hack on the GHC internals - though not a small task by any means.
personally, I rarely find the stack dump very useful at all (though I always have high hopes). perhaps I have just had bad experiences with it, but it can often be uninformative or even misleading.
It wouldn't be a dump of the evaluation stack, rather a dump of the lexical call stack - the stack that you see when you do +RTS -xc, or time profiling in GHC. It's much more useful than the evaluation stack, which is usually not terribly informative I agree (though I've heard others say they'd still like to be able to get hold of that too). Cheers, Simon