Evan Laforge
I noticed a recent commit https://phabricator.haskell.org/D578 implements this. This is exciting! But I suppose it's too late for 7.10? Any chance of it making it in?
Heh, I probably should have made some noise about it... But there are still some questions about to what extent to use it (if at all) in the standard libraries, so I doubt it would be a good candidate for a last minute merge to 7.10. I've actually been meaning to start a discussion about where/whether we should use this feature in base, but it slipped by the wayside. Thanks for the reminder!
I should note that to me the most interesting part of this has nothing to do with debugging. If you have a logging system, or tests, you need to have file name and line numbers. I've always done it via a custom preprocessor, but this extension would allow me to get rid of the preprocessor, which is very nice. It also seems simpler than the whole call stack thing because I only care about the first entry of the stack.
Yep, my original motivation was getting access to source locations within embedded DSLs. The call-stack is a nice and easy extension, but I'm not sure how useful it will be in practice, as the first function that doesn't request a CallStack parameter will cut off the stack. This means that the generated stacks will often be quite short, I imagine. Eric