Php/docs/language.namespaces.definitionmultiple
Defining multiple namespaces in the same file
(PHP 5 >= 5.3.0, PHP 7, PHP 8)
Multiple namespaces may also be declared in the same file. There are two allowed syntaxes.
Example #1 Declaring multiple namespaces, simple combination syntax
<?phpnamespace MyProject;const CONNECT_OK = 1;class Connection { /* ... */ }function connect() { /* ... */ }namespace AnotherProject;const CONNECT_OK = 1;class Connection { /* ... */ }function connect() { /* ... */ }?>
This syntax is not recommended for combining namespaces into a single file. Instead it is recommended to use the alternate bracketed syntax.
Example #2 Declaring multiple namespaces, bracketed syntax
<?phpnamespace MyProject {const CONNECT_OK = 1;class Connection { /* ... */ }function connect() { /* ... */ }}namespace AnotherProject {const CONNECT_OK = 1;class Connection { /* ... */ }function connect() { /* ... */ }}?>
It is strongly discouraged as a coding practice to combine multiple namespaces into the same file. The primary use case is to combine multiple PHP scripts into the same file.
To combine global non-namespaced code with namespaced code, only bracketed syntax is supported. Global code should be encased in a namespace statement with no namespace name as in:
Example #3 Declaring multiple namespaces and unnamespaced code
<?phpnamespace MyProject {const CONNECT_OK = 1;class Connection { /* ... */ }function connect() { /* ... */ }}namespace { // global codesession_start();$a = MyProject\connect();echo MyProject\Connection::start();}?>
No PHP code may exist outside of the namespace brackets except for an opening declare statement.
Example #4 Declaring multiple namespaces and unnamespaced code
<?phpdeclare(encoding='UTF-8');namespace MyProject {const CONNECT_OK = 1;class Connection { /* ... */ }function connect() { /* ... */ }}namespace { // global codesession_start();$a = MyProject\connect();echo MyProject\Connection::start();}?>
