Copyright © 2017 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
| #!/bin/bash | |
| JENKINS_URL=$1 | |
| NODE_NAME=$2 | |
| NODE_SLAVE_HOME='/home/build/slave' | |
| EXECUTORS=1 | |
| SSH_PORT=22 | |
| CRED_ID=$3 | |
| LABELS=build | |
| USERID=${USER} |
| Latency Comparison Numbers | |
| -------------------------- | |
| 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 |
| -- A sequential series of parallel program fragments in `f`: | |
| type SeqPar f a = Free (FreeAp f) a | |
| liftFA :: forall f a. f a -> SeqPar f a | |
| liftFA = pure >>> pure | |
| liftSeq :: forall f a. Free f a -> SeqPar f a | |
| liftSeq fa = foldFree fa liftFA | |
| liftPar :: forall f a. FreeAp f a -> SeqPar f a |
| package com.example.http4s | |
| import cats.data.OptionT | |
| import cats.effect.Sync | |
| import org.http4s.dsl.impl.Path | |
| import org.http4s.headers.Allow | |
| import org.http4s.{AuthedRoutes, HttpRoutes, Method, Response, Status} | |
| object Route { | |
| def of[F[_]: Sync](pf: PartialFunction[Path, Map[Method, HttpRoutes[F]]]): HttpRoutes[F] = HttpRoutes[F] { req => |