:: Ord a => [a] -> [a] is:exact -package:stm-containers -package:amazonka-core -package:Cabal -package:mono-traversable -package:base -package:witherable -package:vector-algorithms -package:Cabal-syntax -package:ghc -package:extra -package:containers 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.