until -package:numeric-prelude -package:base-prelude -package:distribution-opensuse -package:extra -package:basic-prelude -package:ghc-lib-parser -package:hledger-web -package:numhask -package:snap-core -package:classy-prelude 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.