September 2018
Intermediate to advanced
398 pages
9h 43m
English
Content preview from Scala Programming Projects
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Summary
We covered some challenging concepts in this chapter. Type classes are also used in other functional programming languages, such as Haskell.
For convenience, the following table summarizes the type classes that we enumerated in this chapter:
| Name | Method | Law(s) | Example(s) |
| Semigroup |
def combine( x: A, y: A) : A |
Associativity |
Option(1) |+| None |+| Option(2) // res5: Option[Int] = Some(3) |
| Monoid | def empty: A | Identity |
Vector(1,2,3).combineAll // res8: Int = 6 Vector("1", "2", "3").foldMap(s => (s,s.toInt))
// res10: (String, Int) = (123,6) |
| Functor | def map[A, B] (fa: F[A]) (f: A => B): F[B] | Identity, Composability |
def square(x: Double): Double = x * xdef squareVector: Vector[Double] => Vector[Double] = Functor[Vector].lift(square) ... |
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.