The editor will guide you to quote the class name (php version)

In the previous article, we learned about sub-namespaces and how to define sub-namespaces. If necessary, please read "What is the sub-namespace of php namespace?" 》. This time we will introduce to you how to use reference class names. You can refer to it if necessary.

First let’s look at an example.

file1.php file code

<?php
namespace Foo\Bar\subnamespace; 

const FOO = 1;
function foo() {}
class foo
{
    static function staticmethod() {}
}
?>

file2.php file code

<?php
namespace Foo\Bar;
include &#39;file1.php&#39;;

const FOO = 2;
function foo() {}
class foo
{
    static function staticmethod() {}
}

/* 非限定名称 */
foo(); // 解析为函数 Foo\Bar\foo
foo::staticmethod(); // 解析为类 Foo\Bar\foo ，方法为 staticmethod
echo FOO; // 解析为常量 Foo\Bar\FOO

/* 限定名称 */
subnamespace\foo(); // 解析为函数 Foo\Bar\subnamespace\foo
subnamespace\foo::staticmethod(); // 解析为类 Foo\Bar\subnamespace\foo,
                                  // 以及类的方法 staticmethod
echo subnamespace\FOO; // 解析为常量 Foo\Bar\subnamespace\FOO
                                  
/* 完全限定名称 */
\Foo\Bar\foo(); // 解析为函数 Foo\Bar\foo
\Foo\Bar\foo::staticmethod(); // 解析为类 Foo\Bar\foo, 以及类的方法 staticmethod
echo \Foo\Bar\FOO; // 解析为常量 Foo\Bar\FOO
?>

Let’s take a good look at this example. In this example, the most prominent thing is foo::staticmethod(), have you noticed that no matter which usage we use, we need to use "foo::staticmethod()", but this what does it mean? Let’s find out in detail.

According to the example we can see that "staticmethod()" is actually the name of a static method, and "foo::" is based on "foo()" is parsed.

Class names in the PHP namespace can be referenced in three ways:

• unqualified names, or class names that do not include the prefix , For example "$c=new foo();" or "foo::staticmethod();". If the current namespace is space, foo will be resolved to space\foo. If foo is global code, code not contained in any namespace, then foo will be parsed as foo.

• Warning: If a function or constant in a namespace is not defined, an unqualified function or constant name will resolve to a global function or constant name.

• Qualified name, or name containing the prefix , for example $c = new espace\foo(); or space\foo::staticmethod();. If the current namespace is space, foo will be resolved to space\space\foo. If the code using foo is global and does not contain code in any namespace, foo will be resolved into space\foo.

• Fully qualified name, or a name that includes a global prefix operator, for example, $c = new \space\foo(); or \space\foo::staticmethod();. In this case, foo is always resolved to the literal name (literal name)space\foo in the code.

Functions with fully qualified names will be resolved at compile time when calling classes and constants.

Non-fully qualified names will be converted at compile time according to import rules.

In a namespace, all qualified names that are not converted according to import rules are preceded by the current namespace name.

That’s all. If you want to know anything else, you can click here. → →php video tutorial

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