until -package:numeric-prelude -package:base-prelude -package:distribution-opensuse -package:extra -package:ghc -package:linear-base -package:mixed-types-num -package:yesod-paginator -package:streaming -package:language-bash -package:cabal-install-solver -package:free 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.