justusadam / marvin-interpolate

Compile time String interpolation

Simple string interpolation

You can find the documentation for this library as part of the marvin docs on readthedocs.

marvin-interpolate's Issues

Update to work with GHC 8.6

Hey @JustusAdam

On this line: https://github.com/JustusAdam/marvin-interpolate/blob/master/src/Marvin/Interpolate.hs#L107 we're not handling the empty list case.

I mentioned this to you earlier and it's because of this change: https://gitlab.haskell.org/ghc/ghc/wikis/migration/8.6#MonadFailDesugaringbydefault

Basically we need to handle the [] case and not just the (name:rest) case.
This seems like a straightforward change except I'm not sure what we should do in [] case. If I just add [] -> error "foo" it compiles but it's not clear to me from the code what should really happen here. I've never worked with TH so the code is a bit of a mystery to me.

Add escape sequence for } in $() interpolator

Ambiguous fixity with two infix operators in expression

interpolated expressions do not work if there are more than one infix operators, i.e. record ^. field1. field2

Fixities can be retrieved for in-scope bindings in template-haskell using reifyFixity. That doesn't work well with haskell-src-meta though, because it expects a list, not a lookup function.

A possible clean solution is not using haskell-src-meta all and instead asking the GHC library to do the parsing and then translate that to template haskell decls.

Originally reported in #2 and #3, similar issue found in ennocramer/floskell#9