Documentation

DerivingVia wrapper for strongweak instances.

We can't use Generically conveniently because we need to talk about two data types, not one -- we would have to do something like Generically (Tagged w s), which is ugly. So we instead define our own adorable little "via type" here!

Use like so:

data XYZ (s :: Strength) = XYZ
  { xyz1 :: SW s Word8
  , xyz2 :: Word8
  , xyz3 :: ()
  } deriving stock Generic
deriving via (GenericallySW (XYZ 'Strong) (XYZ 'Weak)) instance Weaken (XYZ 'Strong)
deriving via (GenericallySW (XYZ 'Strong) (XYZ 'Weak)) instance Strengthen (XYZ 'Strong)

TODO can't figure out a way around multiple standalone deriving declarations :(