There are many postgres string types (I'm dealing with the cidr and uuid types right now) with no Result instance in postgresql-simple, and defining one is tedious.

One solution is to extend okText to include them, so that the user can just read them as String, ByteString, or Text.

Or, if you export the compat, mkCompats, and doConvert functions (and make them more user friendly), it would be a lot easier to define one's own instance of Result for types like cidr and uuid.