Instructions for using class-level constants in php5.5

I studied php5.5 yesterday and found that there is a new feature called class-level constants. Let me briefly share my study notes with you.

Not long ago, PHP released the first stable version of 5.5, which introduced a class-level constant named `CLASS`. This constant is valid for all classes and returns the full name of the class.

The code is as follows

代码如下	复制代码
namespace vendorpackage; class Foo { // ... } var_dump(Foo::CLASS); //上面脚本输出 string(18) "vendorpackageFoo".

Copy code

namespace vendorpackage;
class Foo
{
// ...
}
var_dump(Foo::CLASS);
//The above script outputs string(18) "vendorpackageFoo".

代码如下	复制代码
namespace vendorpackage; class Foo { // ... } var_dump(__NAMESPACE__ . 'Foo');

Why use it

Why should we use such a constant? Of course it is not just to get the full name of the class like the example above. We can also achieve the same effect using __NAMESPACE__, and php5.3 can be used:

The code is as follows

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代码如下	复制代码
use vendorpackageFoo; class FooTest extends PHPUnit_Framework_TestCase { public function testBarCanBeProcessed() { $bar = $this->getMock('vendorpackageBar'); $foo = new Foo; $foo->process($bar); // ... } }

namespace vendorpackage;
class Foo
{
// ...
}
var_dump(__NAMESPACE__ . 'Foo');

代码如下	复制代码
use vendorpackageFoo; use vendorpackageBar; class FooTest extends PHPUnit_Framework_TestCase { public function testBarCanBeProcessed() { $bar = $this->getMock(Bar::CLASS); $foo = new Foo; $foo->process($bar); // ... } }

However, when you need to fully qualify the name, the namespace references the class namespace alias... then it gets interesting

Related labels：

one time Instructions for use Function Discover study constant yesterday

source：php.cn

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