:: Ord a => [a] -> [a] -package:html-entities -package:ghc is:exact -package:errors -package:imports -package:safe -package:witherable -package:statistics -package:lens -package:containers -package:basement -package:amazonka-core 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.