readsPrec package:polyparse

readsPrecByParsePrec :: (Int -> TextParser a) -> Int -> ReadS a
polyparse Text.Parse
If you have a TextParser for a type, you can easily make it into a Read instance, by throwing away any error messages.
readsPrecByParsePrec :: (Int -> TextParser a) -> Int -> ReadS a
polyparse Text.Parse.ByteString
If you have a TextParser for a type, you can easily make it into a Read instance, by throwing away any error messages. Use of this wrapper function is NOT recommended with ByteString, because there is a lot of inefficiency in conversions to/from String.