php - 是否可以在没有类的情况下使用命名空间

Question

是否可以在没有类的情况下使用命名空间？

例如：

namespace Foo;
// rest of the procedural code and functions

问是因为我知道命名空间只在有类的地方使用。

谢谢你的帮助。

Answer 1

是的，您可以使用没有类的命名空间，例如：

//demo.php file
namespace FooDemo;
function first() { return "First"; }
function second() { return "Second"; }
function third() { return "Third"; }

//test.php file
require_once 'demo.php';
foreach (array("first","second","third") as $funcs) {
    echo call_user_func('FooDemo\\'.$funcs);
}

你的意思是这样的吗

Answer 2

是的。见documentation。

提炼：

<?php
namespace Foo\Bar;
include 'file1.php';

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

/* Unqualified name */
foo(); // resolves to function Foo\Bar\foo
foo::staticmethod(); // resolves to class Foo\Bar\foo, method staticmethod
echo FOO; // resolves to constant Foo\Bar\FOO

/* Qualified name */
subnamespace\foo(); // resolves to function Foo\Bar\subnamespace\foo
subnamespace\foo::staticmethod(); // resolves to class Foo\Bar\subnamespace\foo,
                              // method staticmethod
echo subnamespace\FOO; // resolves to constant Foo\Bar\subnamespace\FOO

/* Fully qualified name */
\Foo\Bar\foo(); // resolves to function Foo\Bar\foo
\Foo\Bar\foo::staticmethod(); // resolves to class Foo\Bar\foo, method staticmethod
echo \Foo\Bar\FOO; // resolves to constant Foo\Bar\FOO
?>