On Mon, 3 Aug 2020, Levent Erkok wrote:
I’m quite interested in this, especially as doctest on GHC 8.10 has issues: https://github.com/sol/doctest/issues/264
interesting
Furthermore, compiling doctests would be a huge performance boost and can speed up CI times significantly.
right
I’m curious why your new package does not support IO-tests. Is that a “current” limitation, or is there a fundamental reason why IO-tests ca not be supported using your approach.
It is a deeper problem. doctest just runs GHCi and GHCi follows the built-in rule: If an expression is IO, then run IO and emit its stdio. If not, print the result of "show". That is, in order to make this distinction, doctest-extract would have to know the type of the test expression. However, doctest-extract extracts purely syntactically, and I prefer to keep it this way for simplicity. For now you may use quickCheck's IO testing. But can it check for stdio data? Alternatively I thought about letting the user mark IO examples in some way. Maybe I could ask the user to give a type signature to IO tests and switch on expressions that end with ":: IO".