PHP生成器能否从未捕获的异常中恢复?

在PHP中考虑这个简单的生成器函数。

function createAGenerator() {
    echo 'Before First Yield',"\n";
    yield 'First Yield';
    echo 'Before Second Yield',"\n";
    yield 'Second Yield';
    echo 'Before Third Yield',"\n";
    yield 'Third Yield';
}

如果我用生成器对象的 throw 方法

$generator = createAGenerator();
try {
    $generator->throw(new Exception('Throwing into a Generator'));
} catch(Exception $e) {
    echo 'Caught Exception: ', $e->getMessage(), "\n";
}
echo 'Resuming Main Program Execution',"\n";

生成器函数将重新抛出异常以供我捕获。这一切都如我所料。

然而,我的发电机现在似乎永远卡住了。如果我想继续 next 屈服,或 send 如果在中有一个新值,则生成器似乎刚刚返回 NULL .例如,以下程序

<?php
function createAGenerator() {
    echo 'Before First Yield',"\n";
    yield 'First Yield';
    echo 'Before Second Yield',"\n";
    yield 'Second Yield';
    echo 'Before Third Yield',"\n";
    yield 'Third Yield';
}

$generator = createAGenerator();
try {
    $generator->throw(new Exception('Throwing into a Generator'));
} catch(Exception $e) {
    echo 'Caught Exception: ', $e->getMessage(), "\n";
}
echo 'Resuming Main Program Execution',"\n";

var_dump($generator->send('Some Value'));
var_dump($generator->current());
var_dump($generator->next());
var_dump($generator->current());

返回以下输出。

Before First Yield
Caught Exception: Throwing into a Generator
Resuming Main Program Execution
NULL
NULL
NULL
NULL

发电机有办法从中恢复吗?或者,生成器中的未捕获异常是否会“破坏”该生成器的当前实例?