使用关键字和动态类名称

use my\Project\FooClass;

$obj = new FooClass(); // ok
$name = 'FooClass';
$obj2 = new $name(); // throws an error that the class wasn't found

Well, I believe the title and the example were pretty enough explanation of my question, so just - why does this throws an error, and how should I deal with this?

Sadly, this is not possible due to the way PHP imports/aliases from namespaces. This can be remedied by using literal namespace definitions, though it no doubt sucks.

As follows:

$r = "my\\Project\\FooClass";
$k = new $r();

There is a patch in the works, or at the very least, it was on PHP's bug report a couple of months back. They will hopefully do something about it.

If it bothers you, you can use class_alias() to remedy it, by the way.

try:

$obj2 = new $name;

Remove the parenthesis

Alternatively:

$obj2 = new {$name}();

Can't explain why this doesn't work. But for how to deal with it:

$name = 'FooClass';
$name = "my\\Project\\FooClass\\" . $name; // prepend namespace
$obj2 = new $name();