to pause the video stream during the talk. 23 REVIEW C++ COROUTINE IN 10 MINS • Core concepts: promise object, coroutine handle • Keywords: co_return, co_await, co_yield(not covered here) • awaitables https://lewissbaker.github.io/2018/09/05/understanding -the-promise-type • User defined type(s) that stores whatever you want/required Promise Object Coroutine Handle • Literally a handle • Two different coroutine_handle<>, coroutine_handle<Promise> • coroutine_handle<>: resume/destroy coroutine, check status(done) • coroutine_handle<Promise>: provide access to the promise object(promise) Useful to know For convenience:

Non-blocking! writer.Close(); thread x thread yfutures/promises: “buffered channel” Promise promise; Channel::Reader reader = channel.Reader(); reader.Read(); // Blocks! Non-blocking! writer.Close(); thread x thread yfutures/promises: “buffered channel” Promise promise; Channel::Reader reader = channel.Reader(); reader.Read(); // Blocks! Close(); thread x thread yfutures/promises: “buffered channel” Promise promise; Future future = promise.Future(); reader.Read(); // Blocks! Channel::Writer writer

} }8/55 The coroutine promise promise type9/55 Cheat Sheet - Promise Type 1 struct ReturnType / std:: coroutine_traits < ReturnType , ...> { 2 struct promise_type { 3 promise_type (T...); // opt. 4 Awaitable 1 struct Awaitable { 2 bool await_ready (); 3 auto await_suspend (std:: coroutine_handle < promise_type >); 4 auto await_resume (); 5 };12/55 Cheat Sheet: Map of Coroutine Land13/55 Get the cheat Async { struct promise_type { /* ... */ }; };34/55 Setting up the Async object template struct Async { struct promise_type { /* ... */ }; std:: coroutine_handle <promise_type > self ;

ThinkJS ������ ThinkJS ���������� ����������������� ������������� �� ES6/7 ������������ JavaScript Promise��� learn-es2015 ������� ��������� �������� � express/koa �� � sails �� ThinkJS ��� ES6/7 from './base.js'; export default class extends Base { /** * index action * @return {Promise} [] */ indexAction(){ //auto render template file index_index.html return this.display(); ERROR'); } } } JavaScript �� async/await ���� Promise ����� rejected Promise������������������ ����������� catch ������ resolve Promise ������ �����������success������� message � PREVENT_NEXT_PROCESS

from './base.js'; export default class extends Base { /** * index action * @return {Promise} [] */ indexAction(){ //auto render template file index_index.html return this.display(); async/await , if Promise returned a rejected Promise, an exception will be throwed. If it is not important and you want to ignore it, you can make the catch method to return a resolve Promise: After calling higher execution efficiency. For this, you can use Promise.all to implement it. p1 and p2 are processed parallelly and then get both data by using Promise.all . If your projects need to output data like

from './base.js'; export default class extends Base { /** * index action * @return {Promise} [] */ indexAction(){ //auto render template file index_index.html return this.display(); async/await , if Promise returned a rejected Promise, an exception will be throwed. If it is not important and you want to ignore it, you can make the catch method to return a resolve Promise: How To Open But mostly you want to excute parallely to have higher execution efficiency. For this, you can use Promise.all to implement it. export default class extends think.controller.base { async indexAction(){

from './base.js'; export default class extends Base { /** * index action * @return {Promise} [] */ indexAction(){ //auto render template file index_index.html return this.display(); from './base.js'; export default class extends Base { /** * index action * @return {Promise} [] */ indexAction(){ //auto render template file index_index.html return this.display(); /base.js'); module.exports = think.controller(Base, { /** * index action * @return {Promise} [] */ indexAction: function(self){ //auto render template file index_index.html

机测试，如果使用 ab 测试工具，请注意该工具在 Mac 系统下很不稳定，多次测试结果会相差很 大。 ES6/7 参考文档 关于 ES6/7 特性可以参考下面的文档： JavaScript Promise迷你书 learn-es2015 ECMAScript 6 入门 给 JavaScript 初心者的 ES2015 实战 ECMAScript 6 Features ECMAScript Base from './base.js'; export default class extends Base { /** * index action * @return {Promise} [] */ indexAction(){ //auto render template file index_index.html return this.display(); 误，这样就可 以针对不同的错误返回不同的错误信息。 如何忽略异常 使用 async/await 时，如果 Promise 返回了一个 rejected Promise，那么会抛出异常。如果这个异 常不重要需要忽略的话，可以通过 catch 方法返回一个 resolve Promise 来完成。如： export default class extends think.controller.base

ThinkJS 是⼀一款⾼高效、简单易⽤用的 Node.js MVC 框架。基于 ES6 Promise 开发，让异步编程更加简单、⽅方便。 ⾃自动启动服务 ⽀支持 Http、命令⾏行、WebSocket、Restful等多种⽅方式调⽤用 CBD 架构，MVC 模式 基于 Promise，异步编程更加简单 封装了 Db, Cache, Session 等常⽤用功能 开发模式下⽂文件修改后⽴立即⽣生效，⽆无需重启 测也是个⾏行为。 标签 (tag) 是⼀一组⾏行为的集合，是在系统执⾏行过程中切⾯面处调⽤用的。与 EventEmitter 不同，标签⾥里的⾏行为是按 顺序执⾏行的，当前的⾏行为通过 Promise 机制控制后⾯面的⾏行为是否被执⾏行。 当执⾏行⼀一个 http 请求时，会在对应的时机执⾏行如下的标签位： app_init 应⽤用初始化 path_info 解析 path 路径 这⾥里说个技巧：⼀一般系统后台都需要⽤用户登录才能访问，但判断⽤用户是否登录⼀一般都是异步的，不可能在每个 Action ⾥里都去判断是否已经登录。 这时候就可以在 init ⽅方法⾥里判断是否已经登录，并且把这个 promise 返回，后续的 action 执⾏行则是在这个 then 之 后执⾏行。如： ThinkJS ⽀支持前置和后置操作，默认的⽅方法名为 __before 和 __after ，可以通过如下的配置修改：

Coroutines in VGJS – Example void test() { Coro retObj = driver(13); schedule(retObj); //put promise into a VGJS queue, a thread will grab it in its loop if(retObj.ready()) std::cout << "Result " << Coro retObj = driver(13); schedule(retObj); } Coro_promise Coro_promise VGJS Coroutines Coro driver(int i) { co_await promise.initial_suspend(); try { Coro retObj = coroTest(i); coroTest(i); int res = co_await retObj; co_return 0.0f; } catch (...) { promise.unhandled_exception(); } FinalSuspend: co_await promise.final_suspend(); } Coro coroTest(int i) { co_await thread_index_t{