batch_await

[JinjunHan]

batch_await不会回调，目前是第二个，比第一个快回调时候出现的问题

[JinjunHan]

感觉只有按数组顺序逐个回调才能成功

[NianJi]

Fixed: #27

[JinjunHan]

如果一个页面需要请求多个接口来组合数据显示UI，那么怎么使用比较好？
1）每个请求用await()的话，结束时候组合数据，就不能并发请求接口。
2）用batch_await()的话，回调数据是数组，遍历时候还需要判断这个结果属于哪个数据，不太优雅。
还有什么其他方法吗？

[NianJi]

1. We have a design problem with Promise, so use promise to realize concurrent is ugly for now.

We expect:

// concurrent
id promise1 = getPromise1();
id promise2 = getPromise2();

id result1 = await(promise1);
id result2 = await(promise2);

But if you alloc your promise with promise:(COPromiseConstructor)constructor method. Promise does not start directly, until await it. So it became not concurrent.

We are trying to fix this problem. If you have a another good suggestion, we may consider it.

2. Another way is use multiple coroutines， then use channel passing results.

co_launch(^{

      COChan *chan = [COChan chan];
      COChan *chan2 = [COChan chan];

      // first operation
      co_launch(^{

           [chan1 send:result1];
      });

     // second operation
      co_launch(^{

           [chan2 send:result2];
      });

      id result1 = [chan1 receive];
      id result2 = [chan2 receive];
     
});

[NianJi]

I open a issue to discuss this: #30