Mastering Functional Programming

Motivation

Consider that we have two independent computations. Suppose we have two computations that evaluate mathematical expressions, and then we need to combine their results. Also, suppose that their computation is performed under the Either effect type. So, the main idea is that either of the two computations can fail, and if one of them fails, it is the result of interpretation being left with an error, and if it succeeds, the result is Right of some result:

type Fx[A] = Either[List[String], A]def combineComputations[F[_]: Monad](f1: F[Double], f2: F[Double]): F[Double] = for {   r1 <- f1   r2 <- f2 } yield r1 + r2val result = combineComputations[Fx](Monad[Fx].pure(1.0),  Monad[Fx].pure(2.0)) println(result) // Right(3.0)

In the preceding ...