[Haskell-beginners] How to extract from Maybe & Either in GHCi

[Ertugrul Soeylemez]

Christopher Done <chrisdone at googlemail.com> wrote:

> FWIW there is also Data.Either which has the either function.

Only few people seem to realize that 'maybe' and 'either' exist and how
useful they are.  They are defined in the Prelude, so no imports are
necessary.

  either this that . maybe defValue foo $ someMaybeEitherValue

They also help with monadic code:

  getStuff :: IO (Maybe String)

  getStuff >>= maybe (throwIO (MyError "Stuff not available")) putStrLn


Greets,
Ertugrul


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