承诺 - MetaTrader 5程序库

npm i mql5-promise

Promise 示例：

 #include "timer.mqh"
#include "index.mqh"

void OnInit () {
     new Promise(printAndTimoutResolve, "111" )
        .then(printAndReject, "222" ) // then - 如果前一个承诺已解决，则运行
        .ccatch(printAndResolve, "333" ) // ccatch - 在前一个承诺被拒绝时运行
        .ccatch(printAndResolve, "444" )
        .ccatch(printAndResolve, "555" )
        .then(printAndResolve, "666" )
        .finally(printAndResolve, "end" ) // 最后 - 运行任何程序
        .destroy(); // 执行完所有承诺后，清除这些承诺的内存

     Print ( "start" );

     // printAndTimoutResolve 111 // 打印后超时
     // 开始
     // printAndReject 222
     // printAndTimoutResolve 333
     // printAndTimoutResolve 666
     // printAndTimoutResolve end
};

void promiseAllResolve( ulong promiseId, string &prevResult[], string parametr) {
     Print ( "promiseAllResolve " + parametr);
};

void printAndTimoutResolve( ulong promiseId, string prevResult, string parametr) {
     Print ( "printAndTimoutResolve " + parametr);
    Timer::setTimout(resolveByIdStr, 2000 , string (promiseId));
};
void resolveByIdStr( string id) { Promise::resolveById( ulong (id)); }

void printAndResolve( ulong promiseId, string prevResult, string parametr) {
     Print ( "printAndResolve " + parametr);
    Promise::resolveById(promiseId);
};

void printAndReject( ulong promiseId, string prevResult, string parametr) {
     Print ( "printAndReject " + parametr);
    Promise::rejectById(promiseId);
};

例如，Promise:all：

 void OnInit () {
    Promise* list1[] = {
         new Promise(printAndTimoutResolve, "Promise 1" )
            .then(printAndTimoutResolve, "Promise 1.1" )
        ,
         new Promise(printAndReject, "Promise 2" ),
         new Promise(printAndTimoutResolve, "Promise 3" ),
    };

    Promise::all(list1, promiseAllResolve) // 如果所有承诺都已解决，则进行解析
        .then(printAndResolve, "Promise::all resolved" )
        .ccatch(printAndResolve, "Promise::all rejected" )
        .destroy(); // 删除所有承诺

     // printAndTimoutResolve Promise 1
     // 打印并拒绝承诺 2
     // printAndTimoutResolve Promise 3
     // printAndResolve Promise::all rejected
};

Promise example:race：

 void OnInit () {
    Promise* list2[] = {
         new Promise(printAndTimoutResolve, "Promise 1" )
            .then(printAndTimoutResolve, "Promise 1.1" )
        ,
         new Promise(printAndReject, "Promise 2" ),
         new Promise(printAndTimoutResolve, "Promise 3" ),
    };

    Promise::race(list2, printAndResolve, "Promise::race" ) // 在第一个承诺后解析/拒绝
        .then(printAndResolve, "Promise::race resolved" )
        .ccatch(printAndResolve, "Promise::race rejected" )
        .destroy();

     // printAndTimoutResolve Promise 1
     // 打印并拒绝承诺 2
     // printAndTimoutResolve Promise 3
     // 拒绝接受 Promise::race
};

例如 Promise:any：

 void OnInit () {
    Promise* list3[] = {
         new Promise(printAndTimoutResolve, "Promise 1" )
            .then(printAndTimoutResolve, "Promise 1.1" )
        ,
         new Promise(printAndReject, "Promise 2" ),
         new Promise(printAndTimoutResolve, "Promise 3" ),
    };

    Promise::any(list3, printAndResolve, "Promise::any" )
        .then(printAndResolve, "Promise::any resolved" )
        .ccatch(printAndResolve, "Promise::any rejected" )
        .destroy();

     // printAndTimoutResolve Promise 1
     // 打印并拒绝承诺 2
     // printAndTimoutResolve Promise 3
     // printAndResolve Promise::any
     // printAndResolve Promise::any resolved
};