Expansion of "lift" concept

[chris-martin]

I put the polymorphic lift function into the ascii-superset package as a general way to raise ASCII types into larger character sets, e.g. [ASCII.Char] -> Text, so it could be a short memorable name for what I figure is a common operation. What I'm finding now as I'm introducing ASCII subset types, though, is that I also want to use this class for ASCII subsets.

The definition currently looks like this:

class Lift ascii superset where
    -- | Converts from ASCII to any larger type.
    lift :: ascii -> superset

There's nothing stopping us from going ahead and defining instances e.g. instance Lift [HexChar] [ASCII.Char], but then the documentation really needs updating. And it then becomes sort of awkward for the Lift class to be in the ascii-superset package. Because, for instance, instance Lift D10 D16 seems perfectly okay, but it has nothing to do with ASCII supersets, since it only represents a lifting from one ASCII subset to another. I don't think it makes any sense to put Lift into its own package. It is possible that this is merely a documentation issue, and that the ascii-superset package description would just need to be updated along with the Lift class to convey that it also provides a bit of mechanism for talking about subsets.

[chris-martin]

Documentation change is made, I think this okay now. https://github.com/typeclasses/ascii/releases/tag/ascii-superset-1.0.1.13