Mastering Functional Programming

IO combination without Fibers

Consider that we need to compute a sum of two ranges, and then sum the results. A naive way to combine is as follows:

def sequential: IO[Int] = for {   s1 <- sum(1 , 10)   s2 <- sum(10, 20) } yield s1 + s2

In the preceding code, we combine our computations using the Monadic flow. Let's see what happens if we try and run the competition under a benchmark function:

benchmarkFlush(sequential).unsafeRunSync

The result of the preceding execution is as follows:

First, notice that the first range gets computed first. The second range does not even start until the first range finishes. Also notice how both of the threads ...