Jimmy Au jjbubudi

README

Services declared as oneshot are expected to take some action and exit immediatelly (thus, they are not really services, no running processes remain). A common pattern for these type of service is to be defined by a setup and a teardown action.

Let's create a example foo service that when started creates a file, and when stopped it deletes it.

Define setup/teardown actions

Create executable file /opt/foo/setup-foo.sh:

Category theory(範疇論)之什麼是Functor, Applicative, Monad, Semigroup, Monoid?

之前曾經寫過一篇什麼是Monad? ，裡面提到了對於Monad的解釋，而今天進一步解釋這些在Functional Programming中常見到的詞：Functor, Applicative, Monad, Semigroup, Monoid。透過放在一起比較，讓我們更清楚這些之間的差別與關係。

##Functor

在提到Functor之前，請先了解一下scala中map的作用，map可以讓你傳入一個function，而透過這個function是可以從F[A]轉換成F[B]，這裡的F不管他(就是代表外面的包裝不會變)，而裡面的A型態轉成B型態。

例如：

Get boot2docker working with nfs instead of vboxsf.

Tested on:

- Boot2Docker-cli version: v1.6.0
  Git commit: 9894ae9
- Boot2Docker-cli version: v1.6.2
  Git commit: cb2c3bc

	// allows converting one class to another by providing missing fields
	object convert {

	@annotation.implicitNotFound("""
	You have not provided enough arguments to convert from ${In} to ${Out}.
	${Args}
	""")
	trait Convertible[Args, In, Out] {
	def apply(args: Args, in: In): Out
	}

	package com.softwaremill.freemonads

	import cats.free.Free
	import cats.~>
	import cats._, cats.std.all._
	import scala.concurrent.ExecutionContext.Implicits.global
	import scala.concurrent.Future

	sealed trait External[A]
	case class Tickets(count: Int) extends AnyVal

	- name: set swap_file variable
	set_fact:
	swap_file: /{{ swap_space }}.swap

	- name: check if swap file exists
	stat:
	path: "{{ swap_file }}"
	register: swap_file_check

	- name: create swap file

	package nl.mdj.fpinscala

	import scala.concurrent.Future
	import scala.concurrent.duration._

	import akka.actor.ActorSystem
	import akka.pattern.after
	import akka.stream.{ActorFlowMaterializer, FlattenStrategy}
	import akka.stream.scaladsl.{Source => S, Flow}
	import akka.stream.scaladsl.FlowGraph.Implicits._

	sealed trait Interact[A]

	case class Ask(prompt: String)
	extends Interact[String]

	case class Tell(msg: String)
	extends Interact[Unit]

	trait Monad[M[_]] {
	def pure[A](a: A): M[A]

	package com.sergiandreplace.content;

	import android.content.ContentProvider;
	import android.content.ContentValues;
	import android.content.Context;
	import android.content.UriMatcher;
	import android.database.Cursor;
	import android.database.sqlite.SQLiteDatabase;
	import android.net.Uri;
	import android.util.SparseArray;

	package pc

	import akka.actor.Actor
	import akka.actor.Props
	import akka.actor.ActorRef
	import akka.actor.ActorRefFactory

	class Parent extends Actor {
	val child = context.actorOf(Props[Child], "child")
	var ponged = false