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Date: Thu, 28 Jun 2012 19:28:53 +0200
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To: Jared Williams <jared.williams1@ntlworld.com>
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Subject: Re: [PHP-DEV] List comprehensions and generator expressions for PHP
From: nikita.ppv@gmail.com (Nikita Popov)

> No mention of yielding keys in the comprehensions. Presume that would
> work?
Yup, that works too. I also included an example in the mail:

    $firstNames =3D [foreach ($users as $user) yield $user->id =3D>
$user->firstName];

This creates a map from ids to first names.

> The simplest example I could think of using Memcached
> (assuming libmemcached fetch() does return as soon as it recieves an
> item)
>
> Eg.
>
> function *getMulti(Memcached $memcached, array $keys)
> {
> =A0 =A0if ($memcached->getDelayed($keys)) {
> =A0 =A0 =A0 =A0while ($item =3D $memcached->fetch())
> =A0 =A0 =A0 =A0 =A0yield $item['key'] =3D> $item['value'];
> =A0 =A0}
> }
>
> foreach(getMulti($memcached, ['foo', 'bar', ... ]) as $key =3D> $value)
> {
> =A0 =A0 =A0 =A0doSomeWork();
> }
>
> So doSomeWork would be called as soon as a single value is available,
> rather
> than having to wait til all values have returned.
>
> Should in theory work right?

Yup, that should work :)

Nikita