:: Ord a => [a] -> [a] -package:containers -package:ghc -is:exact -package:vector-algorithms -package:base-prelude -package:extra is:exact -package:Cabal -package:basement -package:amazonka-core -package:Cabal-syntax 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.