until -package:numeric-prelude -package:util -package:hedgehog -package:yesod-paginator -package:foundation -package:hosc -package:base-prelude -package:classy-prelude -package:base -package:singletons-base 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.