Copyright © 2016-2018 Fantasyland Institute of Learning. All rights reserved.
A function is a mapping from one set, called a domain, to another set, called the codomain. A function associates every element in the domain with exactly one element in the codomain. In Scala, both domain and codomain are types.
val square : Int => Int = x => x * x
| /** | |
| * Working with shapeless' records is great. However, you are limited to using only String, Integer, Boolean, and | |
| * (package) Objects as singleton keys as the singleton machinery requires a stable point (I don't really fully | |
| * understand this part but I have an intuition). I had asked if there was a way to use a tuple or case-class | |
| * as a key in the shapeless gitter channel and no one really knew. | |
| * | |
| * I was reading the shapeless source for the Witness type and an idea came to mind: since we can use a package Object | |
| * as a key, what if that key extends a trait (an abstract class can work as well)? Can we use those objects as | |
| * singleton keys and access the values specified in the trait? | |
| * |
A primer/refresher on the category theory concepts that most commonly crop up in conversations about Scala or FP. (Because it's embarassing when I forget this stuff!)
I'll be assuming Scalaz imports in code samples, and some of the code may be pseudo-Scala.
A functor is something that supports map.
##Scala eXchange 2014 slides
collected by Adam Warski
Feel free to complete the list!
The Binary Compatibility Challenge by Martin Odersky
A Skeptic's Look at scalaz' "Gateway Drugs”: A Practical Exploration by Brendand McAdams
| #!/bin/sh | |
| exec scala -savecompiled "$0" $@ | |
| !# | |
| // | |
| // Copyright (C) 2009-2013 Typesafe Inc. <http://www.typesafe.com> | |
| // Modified 2014 AI2 <http://www.allenai.org> | |
| // | |
| // This script will check that the commit is correctly formatted. It only checks files that are to be committed. | |
| // To be run this file should be at `.git/hooks/pre-commit`. |
| import play.api.libs.json._ | |
| import play.api.libs.functional.syntax._ | |
| sealed trait Parent { | |
| val typ: String | |
| } | |
| case class Foo(blabla: Long, override val typ: String = "foo") extends Parent |
| package json | |
| import reactivemongo.bson._ | |
| import reactivemongo.bson.handlers.DefaultBSONHandlers._ | |
| import play.api.libs.json._ | |
| import play.api.libs.json.Json._ | |
| import play.api.libs.json.util._ | |
| import play.api.libs.json.Writes._ | |
| import play.api.libs.functional.syntax._ |
| /** | |
| * D Holbrook | |
| * | |
| * Code Club: PO1 | |
| * | |
| * (*) Define a binary tree data structure and related fundamental operations. | |
| * | |
| * Use whichever language features are the best fit (this will depend on the language you have selected). The following operations should be supported: | |
| * | |
| * Constructors |
| Latency Comparison Numbers (~2012) | |
| ---------------------------------- | |
| L1 cache reference 0.5 ns | |
| Branch mispredict 5 ns | |
| L2 cache reference 7 ns 14x L1 cache | |
| Mutex lock/unlock 25 ns | |
| Main memory reference 100 ns 20x L2 cache, 200x L1 cache | |
| Compress 1K bytes with Zippy 3,000 ns 3 us | |
| Send 1K bytes over 1 Gbps network 10,000 ns 10 us | |
| Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD |
