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Is there a way to perform a case on the value stored within a monad without having to bind a name to it?
i.e. instead of doing this:
c <- getChar case c of ... Is there a way to do this:
mcase getChar of ... Alternatively, it would be nice if the case statement could be partially applied so:
case of ... would be desugared to:
\a -> case a of ... So you could do this:
getChar >>= case of ... 
508
A monadic function is a function that produces a monadic value. ( Note that we said nothing about its input type) and. Functions of the form f :: a -> m b , where a is the type of the inner value of the monad. ( Call these classic monadic functions)
monads are used to address the more general problem of computations (involving state, input/output, backtracking, ...) returning values: they do not solve any input/output-problems directly but rather provide an elegant and flexible abstraction of many solutions to related problems.
In functional programming, a monad is a software design pattern with a structure that combines program fragments (functions) and wraps their return values in a type with additional computation.
List as a data structure is not a Monad, but the fact that Scala's List implements flatMap is what gives it its monadic super-powers. It also needs to fulfil associativity, left unit and right unit laws to qualify as a Monad.
The proposal mentioned by FUZxxl was now implemented in GHC since 7.6.1, it's called LambdaCase.
Now you can do:
{-# LANGUAGE LambdaCase #-} getChar >>= \case ... Note the \ before the case keyword and the fact that there is no of in that case.
78
No, not really, but you can move the case into another function and apply it to the result of a monadic action.
f x = case x of ... main = do f <$> getChar Alternativly, the following is possible:
getChar >>= \x -> case x of ... If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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