Maybe

The Maybe type in cyclops-react is a totally lazy Option or Optional type modelled on Maybe from Haskell. Maybe's can represent one of two states - Just a value (present / some ) or None.

Class Hiearchy

Maybe is an instance of the following cyclops types (and others) ApplicativeFunctor, Filterable, Foldable, Functor, MonadicValue1, To, Value,Visitable and Zippable

Pattern matching

In cyclops we can use the visit operator to pattern match on the state the Maybe is in.

int result = Maybe.just(10)
                  .visit(some->some+5,()->-1); 

Recover / orElse /coflatMap

Recover orElse and coflatMap can be used to manage Maybe's that aren't present and provide a default value.

Maybe.just(10)
     .recover(-1); //Maybe[10]
Maybe.none()
     .recover(-1); //Maybe[-1]
 

int result = Maybe.none()
                  .orElse(-1); //-1

Maybe.none()
     .coflatMap(maybe->maybe.visit(Maybe::get,()->-1); //Maybe[-1]

Sequence

Accumulating

Recursion