until -package:numeric-prelude -package:base-prelude -package:hosc -package:numhask -package:Cabal -package:singletons-base -package:streaming -package:termonad -package:scalpel -package:base-compat -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.