Computation

Monad of extensible effects. Use the !! infix type alias instead.

For example:

type MyComputationType1 = String !! (MyState & MyError)

type MyComputationType2 = String !! Any

MyComputationType1 is a type of computations that return String and reqest 2 effects: MyState and MyError.

MyComputationType2 is a type of computations that return String and reqest no effects (type Any means empty set).

All requested effects must be handled (discharged from the computation), by using Handlers, before the result can be obtained as a plain (non monadic) value.

To handle some or all requested effects, use handleWith:

val myComputation2 = myComputation.handleWith(myHandler)

As soon as all effects are handled, the result can be obtained with run:

val result = someComputation
  .handleWith(someHandler1)
  .handleWith(someHandler2)
  .handleWith(someHandler3)
  .run