until -package:numeric-prelude -package:util -package:xmonad-contrib -package:LambdaHack -package:mixed-types-num -package:extra -package:elerea -package:language-bash -package:base-prelude -package:snap-core 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.