record-hasfield

This package provides a version of "GHC.Records" as it will be after the implementation of GHC proposal #42, which reads:

-- | Constraint representing the fact that the field @x@ can be get and set on
--   the record type @r@ and has field type @a@.
class HasField x r a | x r -> a where
    -- | Function to get and set a field in a record.
    hasField :: r -> (a -> r, a)

In GHC these will be magically solved, but this package doesn't provide that. This package does provide extra helper functions for working with the HasField type class.