| //> using scala "2.13.10" | |
| //> using lib "org.typelevel::cats-effect:3.3.14" | |
| //> using lib "co.fs2::fs2-core:3.4.0" | |
| //> using lib "org.neo4j.driver:neo4j-java-driver:5.3.0" | |
| import cats.effect.IO | |
| import fs2.Stream | |
| import org.neo4j.driver.summary.ResultSummary | |
| import org.neo4j.driver.types.{IsoDuration => NeoDuration, Point => NeoPoint} |
People trying to learn about FP will heard about the M word sooner than latter. Personally I believe that way sooner than what is required, and recommended; which is what makes folks to be confused about it.
This is my humble attempt to try to briefly explain the concept, while also arguing that you shouldn't really care too much about it. This all with the intention to make your FP journey more enjoyable 😄 — without further ado, let's start.
| package example | |
| import cats.effect.IO | |
| import cats.effect.kernel.Ref | |
| import cats.syntax.all._ | |
| import scala.concurrent.duration._ | |
| object MultiTaskRunner { | |
| /** Allows a task to report its progress. */ |
| package example | |
| import cats.effect.Async | |
| import cats.effect.std.Queue | |
| import cats.effect.syntax.all._ | |
| import cats.syntax.all._ | |
| import scala.concurrent.ExecutionContext | |
| object HighLowPriorityRunner { |
| // scala 2.13.6 | |
| sealed trait RockPaperScissorsMove extends Product with Serializable | |
| object RockPaperScissorsMove { | |
| final case object Rock extends RockPaperScissorsMove | |
| final case object Paper extends RockPaperScissorsMove | |
| final case object Scissors extends RockPaperScissorsMove | |
| } | |
| trait Game { |
| import cats.syntax.all._ | |
| import cats.effetc.{Concurrent, Timer} | |
| import cats.effect.concurrent.Ref | |
| import fs2.Stream | |
| import fs2.concurrent.SignallingRef | |
| import scala.concurrent.duration.FiniteDuration | |
| def stopIfNoNewElementsAfter[F[_] : Concurrent : Timer, A]( | |
| stream: Stream[F, A], |
Probably not the most poetic nor academic or well written phrase, but let me express in plain English why I end up choosing Functional Programming.
Over my time coding (which I have to clarify that has been short) I have learned two important things about code.
(mostly from the experience of many more veteran colleagues)
| java.util.concurrent.RejectedExecutionException: Task cats.effect.internals.IOShift$Tick@1d4aa74b rejected from java.util.concurrent.ThreadPoolExecutor@3a57c4b4[Terminated, pool size = 0, active threads = 0, queued tasks = 0, completed tasks = 3] | |
| at java.base/java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:2055) | |
| at java.base/java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:825) | |
| at java.base/java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1355) | |
| at scala.concurrent.impl.ExecutionContextImpl.execute(ExecutionContextImpl.scala:21) | |
| at cats.effect.internals.IOShift$$anon$1.apply(IOShift.scala:28) | |
| at cats.effect.internals.IOShift$$anon$1.apply(IOShift.scala:26) | |
| at cats.effect.internals.IORunLoop$RestartCallback.start(IORunLoop.scala:341) | |
| at cats.effect.internals.IORunLoop$.cats$effect$internals$IORunLoop$$loop(IORunLoop.scala:119) | |
| at cats.effect.internals.IORunLoop$.start(IORunLoop.scala:34) |
| /** Neotypes demo for ScalaMDE 2019. */ | |
| // Imports. | |
| // // FS2. | |
| import fs2.Stream | |
| // // Neotypes. | |
| import neotypes.{GraphDatabase, Session} | |
| import neotypes.implicits.all._ | |
| import neotypes.cats.effect.implicits._ |
| #!/usr/bin/env amm | |
| import $ivy.`com.sun.mail:javax.mail:1.6.2` | |
| import javax.mail._ | |
| import javax.mail.internet._ | |
| import java.time.{ZoneId, ZonedDateTime} | |
| import java.util.{Date, Properties} | |
| import scala.jdk.CollectionConverters._ | |
| final case class Participant(name: String, email: String) |