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mheinzel/LetIf.hs

Created August 16, 2017 13:07
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LetIf.hs
import Control.Monad.Trans.Maybe
import Control.Monad.IO.Class (liftIO)
prog x = do
print "hi"
runMaybeT $ do
Right y <- return x
liftIO $ print y -- will only be executed if x matched the pattern `Right y`
print "bye"
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