(PHP 5 >= 5.3.0, PHP 7, PHP 8)
Quando um namespace não é definido, todas as definições de classes e funções são
colocadas no espaço global, como era no PHP antes de os namespaces serem
suportados. Prefixar um nome com \ especificará que
o nome é necessário no espaço global, mesmo no contexto do
namespace.
Exemplo #1 Usando a especificação do espaço global
<?php
namespace A\B\C;
/* Esta função é A\B\C\fopen */
function fopen() {
/* ... */
$f = \fopen(...); // chama a função fopen global
return $f;
}
?>Included files will default to the global namespace.
<?php
//test.php
namespace test {
include 'test1.inc';
echo '-',__NAMESPACE__,'-<br />';
}
?>
<?php
//test1.inc
echo '-',__NAMESPACE__,'-<br />';
?>
Results of test.php:
--
-test-Note that variables aren't part of the namespace so they are always global (or scoped to function, etc.) and can't be accessed the same way as other namespace stuff.
So no:
namespace Foo;
$var = "hello";
echo \Foo\$var;In namespaced context the Exception class needs to be prefixed with global prefix operator.
<?php
namespace hey\ho\lets\go;
class MyClass
{
public function failToCatch()
{
try {
$thing = somethingThrowingAnException();
} catch (Exception $ex) {
// Not catched
}
}
public function succeedToCatch()
{
try {
$thing = somethingThrowingAnException();
} catch (\Exception $ex) {
// This is now catched
}
}
}To define an associative array (hash) so that it is part of the namespace, instead of going into the global namespace, just declare it as const, istead of as a variable.
This is handy for lookup tables, config settings, etc.
// Example. Instead of writing:
$my_datatypes = [
"sterility" => [
"xlsx" => [
"Sample Type",
"Run Pass/Fail",
"Result"
],
"db" => [
"SampleType",
"RunPassFail",
"Result"
]
]
];
// ...declare the lookup table like this:
const MY_DATATYPES = [
"sterility" => [
"xlsx" => [
"Sample Type",
"Run Pass/Fail",
"Result"
],
"db" => [
"SampleType",
"RunPassFail",
"Result"
]
]
];
// ...and it will be declared within the current namespace.