until -package:numeric-prelude -package:util -package:hedgehog -package:yesod-paginator -package:foundation -package:snap-core -package:utility-ht -package:classy-prelude -package:cabal-install-solver -is:exact 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.