until -package:numeric-prelude -package:language-bash -package:distribution-opensuse -package:LambdaHack -package:prelude-compat -package:yesod-paginator -package:singletons-base -package:clash-prelude -package:protolude -package:streaming 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.