Edit
Report a Bug
Namespaces
Table of Contents
- Namespaces overview
- Defining namespaces
- Declaring sub-namespaces
- Defining multiple namespaces in the same file
- Using namespaces: Basics
- Namespaces and dynamic language features
- namespace keyword and __NAMESPACE__ constant
- Using namespaces: Aliasing/Importing
- Global space
- Using namespaces: fallback to global function/constant
- Name resolution rules
- FAQ: things you need to know about namespaces
add a note
User Contributed Notes 3 notes
up
down
42
3 years ago
The keyword 'use' has two different applications, but the reserved word table links to here.
It can apply to namespace constucts:
file1:
<?php namespace foo;
class Cat {
static function says() {echo 'meoow';} } ?>
file2:
<?php namespace bar;
class Dog {
static function says() {echo 'ruff';} } ?>
file3:
<?php namespace animate;
class Animal {
static function breathes() {echo 'air';} } ?>
file4:
<?php namespace fub;
include 'file1.php';
include 'file2.php';
include 'file3.php';
use foo as feline;
use bar as canine;
use animate;
echo \feline\Cat::says(), "<br />\n";
echo \canine\Dog::says(), "<br />\n";
echo \animate\Animal::breathes(), "<br />\n"; ?>
Note that
felineCat::says()
should be
\feline\Cat::says()
(and similar for the others)
but this comment form deletes the backslash (why???)
The 'use' keyword also applies to closure constructs:
<?php function getTotal($products_costs, $tax)
{
$total = 0.00;
$callback =
function ($pricePerItem) use ($tax, &$total)
{
$total += $pricePerItem * ($tax + 1.0);
};
array_walk($products_costs, $callback);
return round($total, 2);
}
?>
up
down
-29
9 months ago
Be warned that it is not trivial to convert a project to use namespaces. If you add the same namespace to the top of all your files, your application will break.
All objects in the global namespace, such as ArrayObject, must have a backslash (\) prepend to them.
If you use get_class() and instanceof, you will have to make adjustments here to.
If you have an autoloader, you will need to change its behavior.
It can be done, but subtle errors can creep in and are tedious to rectify.
up
down
-62
1 year ago
Strange, it worked only when I removed the backslash before feline.
So like this is OK : echo feline\Cat::says()
add a note