:: Ord a => [a] -> [a] is:exact -package:html-entities -package:errors -package:lens -package:integration -package:lifted-base -package:base-prelude -package:vector-algorithms -package:ghc -package:witherable -package:generic-deriving -package:Cabal package:parsers
Take a parser that may consume input, and on failure, go back to where
we started and fail as if we didn't consume input.