haskell - How to use non-monadic functions in a bind operation -

haskell - How to use non-monadic functions in a bind operation -

i sense should know this, how utilize frommaybe in 1 line instead of breaking 2 let?

main = maybeport <- lookupenv "port" allow port = frommaybe "4020" maybeport putstrln $ "listening on:" ++ port

you can utilize fmap or <$> this:

import control.applicative ((<$>)) main = port <- frommaybe "4020" <$> lookupenv "port" putstrln $ "listening on:" ++ port

haskell monads