Importing variable namespaces

Question

Would it be possible to import namespaces using a variable like this:

$namespace = 'User\Authorization\Certificate';
use $namespace;

Obviously this won't run as use statement expects a constant but is there a workaround?

Edit: Discovered a gem (only in PHP > 5.3): class_alias($namespace, alias); which does pretty much the same thing with use User\Authorization\Certificate as alias; so will be using that.

Well I'm combining the require_once & use statements into an import(..) function with the help of very structured class and folder hierarchy. — Teoman Soygul
– Teoman Soygul, Commented Jun 19, 2011 at 20:17
Is it considerable to modify the content of the files you require on the fly to introduce your namespace? — hakre
– hakre, Commented Jun 19, 2011 at 21:00

Charles · Accepted Answer · 2011-06-19 19:33:09Z

2

While it isn't possible to pass a namespace in a variable to use, you can place the namespace and the expected "short" class name in a variable and use that in most places where you'd need it, like invoking new.

$namespace = '\foo\bar';
$class = 'baz';
$fully_qualified = $namespace . '\\'. $class; // \foo\bar\baz
$a_foo_bar_baz = new $fully_qualified(...);
var_dump( $a_foo_bar_baz instanceof $fully_qualified ); // true

answered Jun 19, 2011 at 19:33

Charles

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1 Comment

Teoman Soygul Over a year ago

I went with class_alias(..) function which is pretty much what you're trying to achieve in the code so nice solution.

hakre · Accepted Answer · 2011-06-19 21:11:24Z

0

No, PHP expects the use to follow a namespace, not an expression (which includes not a constant). See Using namespaces: Aliasing/Importing.

However if you change the PHP code on the fly before executing it in some kind of aggregation or compilation phase within your system, you could replace the text with some variable data which looks static enough for PHP then.

But I have no idea if your system is capable of doing so. I could imagine some stream wrapper or stream filter doing this on the fly. It could transparently take care of inserting the variable namespace name.

edited Jun 19, 2011 at 21:11

answered Jun 19, 2011 at 19:31

hakre

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4 Comments

Vinicius Kamakura Over a year ago

changing .php files on the fly, can result in it being truncated to 0 bytes if accessed simultaneously by more than one user, or something like that... i remember having terrible experience with my .txt "databases" vanishing back when php+mysql hosting was so rare that you had to pay for it.

hakre Over a year ago

I don't think that this applies. If so, it would be a problem for the bare require/include already. Changing on the file does not need to actually save the file again btw.

Vinicius Kamakura Over a year ago

you meant loading the .php, changing the text and then using eval()?

hakre Over a year ago

No need for eval, require can be used. See stream wrapper

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