until -package:numeric-prelude -package:streaming -package:yesod-paginator -package:mixed-types-num -package:llvm-hs-pure -package:singletons-base -package:faktory -package:hedgehog -package:ghc package:dunai
Similar to Yampa's delayed switching. Loses a b in case of an
exception.
Run the first
msf until the second one produces
True
from the output of the first.