[Haskell-cafe] Decorating exceptions with backtrace information

Michal J Gajda mgajda at mimuw.edu.pl
Sat May 9 12:23:57 UTC 2020

I agree with you that is a great idea!

I can add a few more real world examples:
* we get exception from a foreign library that we bound,
* we get an exception from a platform (I believe Windows supports
throwing exceptions to programs),
* user presses CTRL-C and we want to know where our program hanged.
* we get infamous <<loop>>, because in theory nobody wants
non-terminating programs, but in practice everybody gets them

I also use `ExceptT`, `EitherT` for processing large sets of data,
because that allows me to contain the errors efficiently. However from
time to time, I get an error to blow up **and I cannot even locate
which library was guilty**. It would be nice to extract them
automatically and put them into error database before they are

More information about the ghc-devs mailing list