Improve errors in the Focus macro

optics-dev / Monocly

Optics experimentation for Dotty

MIT License

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Improve errors in the Focus macro #22

Closed kenbot closed 2 years ago

kenbot commented 3 years ago

More precise error cases
Better error messages, specifically not including TASTy printouts
Tests for each failure case, as a first class requirement. This could be done with a diagnostic macro that runs everything as is, but returns diagnostic information including error values, rather than generating the real code. This is how it works in Goggles.
I dimly recall that there might be some library out there that makes testing macro failure cases easier, but I can't remember. Maybe it is in the @propensive -o-sphere.

propensive commented 3 years ago

Yes, have a look at https://github.com/propensive/probably :)

kenbot commented 3 years ago

Thanks Jon, I'll check it out!

propensive commented 3 years ago

You can have a look at the changes in this PR I made for Monocle for the sort of code changes required:

https://github.com/optics-dev/Monocle/pull/991

What I didn't make clear enough when I proposed this in Monocle was that you still need to invoke the macro (and hence the test code) from a call site somewhere. All Probably does is guarantees that the tests that get run also get reported at the end of the compilation.