September 2018
Intermediate to advanced
398 pages
9h 43m
English
Content preview from Scala Programming Projects
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Higher-kinded types
It turns out that similar concepts exist with types and kinds:
- The kind of ordinary types such as Int or Boolean is *
- The kind of unary type constructors is * -> *, for instance, Option or List
- The kind of binary type constructors is (*, *) -> *, for instance, Either or Map
Similarly to functions and order, we can order kinds by the number of type arrow -> they have:
- Order 0 (*): Ordinary types such as Int, Boolean, or String
- Order 1 (* -> * or (*, *) -> *): Type constructors Option, Vector, Map, and many more
- Order 2 ((* -> *) -> *): Higher-kinded types Functor, Monad, and many more
A higher-kinded type is a type constructor that has strictly more than one arrow ->. In the following section, we are going to explore ...
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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.
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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.