无法在接收器上下文中放置地图 [英] Impossible to put a map in sink context

问题描述

我想看看在接收器上下文中抛出地图的方式.在这段代码中

I'm trying to see the way of throwing a map in sink context. In this code

class Sunk {
    has $.titanic;
    method sink {
        say "Sinking $!titanic";
    }
}

Sunk.new( :titanic($_) ) for 1..3;

(1..3).map: { Sunk.new( :titanic($_) ) };

for 循环有效地接收所有创建的内容，map 没有.知道为什么吗?

The for loop effectively sinks all the created, the map does not. Any idea why?

此烤肉测试:https:/github.com/perl6/roast/blob/b9bfe1844db25f65a4aeb351a0107f83689cb5c2/S04-statements/sink.t#L27-L32 应该作为测试.地图实际上是在接收器上下文中，但我不知道它是如何按沉没运行"的.它只是运行.

This test in roast:https://github.com/perl6/roast/blob/b9bfe1844db25f65a4aeb351a0107f83689cb5c2/S04-statements/sink.t#L27-L32 is supposed to work as a test for that. And map is effectively in a sink context, but I dont' see how it's "run as sunk". It's simply run.

推荐答案

在您的示例中，map 返回带有 Sunk 对象的 Seq在里面.整个 Seq 是沉没的，它有效地调用了 Seq.iterator.sink-all，它不会沉没它的所有元素:它只是拉通过调用 pull-one 将 Seq 清空，直到返回 IterationEnd.

In your example, the map returns a Seq with Sunk objects in it. The entire Seq is sunk, which effectively calls Seq.iterator.sink-all, which does not sink all of its elements: it just pulls the Seq empty by calling pull-one until IterationEnd is returned.

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