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Date: Tue, 17 Apr 2012 11:17:05 +0200
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To: Ralph Schindler <ralph@ralphschindler.com>
Cc: internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] New Feature: Fully qualified class name resolution as
 scalar with class keyword
From: nikita.ppv@googlemail.com (Nikita Popov)

On Sat, Apr 14, 2012 at 9:50 PM, Ralph Schindler
<ralph@ralphschindler.com> wrote:
> Hi all,
>
> There are many different use cases were in code we expect classes names a=
s
> arguments to functions as fully qualified names. =A0We do this in ZF a lo=
t
> with our Service Location and DI components, but also with our code
> reflection API, etc. =A0A more interesting use case I would like to call =
out
> is with PHPUnit, for example in a test, you might find this:
>
> =A0$mock =3D $this->getMock('A\Namespaced\ClassName');
>
> This becomes cumbersome when you are dealing with lots of strings about l=
ots
> of class names. =A0This is also an area where, currently, namespace
> declaration and use statements offer no real support.
>
> The patch located here:
>
> https://github.com/ralphschindler/php-src/commit/02210d51851a96d723fbedcf=
c64cde9f9ae2b22a
>
> ... implements the ability for a developer to leverage the file's namespa=
ce
> declaration and use statements to be able to produce a scalar (string) of
> the class name that can be then used, for example, as an argument to a
> function elsewhere.
>
> This overloads the "class" keyword, and by virtue of the existing usage o=
f
> "class" this feature is completely backwards compatible. =A0All existing =
tests
> pass. =A0For example, the above PHPUnit snipped would become:
>
> =A0use A\Namespaced\ClassName;
> =A0$mock =3D $this->getMock(ClassName::class);
>
> Another example with reflection:
>
> =A0use SomeOther\FullyNamespaced\ClassElsewhere as CE;
> =A0$r =3D new ReflectionClass(CE::class);
>
> More examples from the test file:
>
> =A0namespace Foo\Bar {
> =A0 =A0class Baz {}
> =A0 =A0var_dump(Moo::CLASS); // "Foo\Bar\Moo"
> =A0}
>
> =A0namespace {
> =A0 =A0use Bee\Bop as Moo,
> =A0 =A0 =A0 =A0Foo\Bar\Baz;
>
> =A0 =A0var_dump(Baz::class); // "Foo\Bar\Baz"
> =A0 =A0var_dump(Boo::class); // "Boo"
> =A0 =A0var_dump(Moo::CLASS); // "Bee\Bop"
> =A0 =A0var_dump(\Moo::Class); // "Moo"
>
> =A0 =A0$class =3D Baz::class; // assign class as scalar to var
> =A0 =A0$x =3D new $class;
> =A0 =A0var_dump($x); =A0object(Foo\Bar\Baz)#1 (0) {}
> =A0}
>
>
> What do you guys think?
Hey Ralph!

I like the proposal :)

A quick note on the patch: As the class name is compile-time
resolvable it should in my eyes also be available as a
`static_scalar`, so that it can be used in initialization lists:

    public function doFoo($withClass =3D ABC::class) {
        new $withClass; // or whatever
    }

To be available as both a `static_scalar` and a general `scalar` one
should put the rule in the `common_scalar` section.

What do you think?

Nikita