What’s new in PHP 5.4? A huge list of major changes!
The PHP 5.4 is now available.As you probably know, the updates that were intended for postponed PHP 6 were added to PHP 5.4.0 instead, so now PHP includes a huge set of new language features and removes several legacy behaviors.
Because of that I created a list of major changes since PHP 5.3 ,along with some examples and brief descriptions of these changes…
Major PHP improvements
Changes since PHP 5.3 version include:
[*]
Added class member access on instantiation. Now you can use fluent interfaces like in Java:
$myCar = (new Car)->setSpeed(100)->setColor('blue');
[*]
Added callable typehint. This typehint allows a string with a function name, a closure, and an array composed of classname (or object) with method name.
<?php
function foo(callable $cb) {
$cb();
}
?>
[*]
Added closure rebinding as parameter to bindTo. Closure::bindTo() has been modified so now it accepts another argument that defines the new scope. This can either be an object if its class is used as the scope, or a class name.
class A {
private $x;
public function __construct($v) {
$this->x = $v;
}
public function getIncrementor() {
return function() { return ++$this->x; };
}
}
class B extends A {
private $x;
public function __construct($v) {
parent::__construct($v);
$this->x = $v*2;
}
}
$a = new A(0);
$b = new B(10);
$ca = $a->getIncrementor();
var_dump($ca());
echo "Testing with scope given as object", "\n";
$cb = $ca->bindTo($b, $b);
$cb2 = Closure::bind($ca, $b, $b);
var_dump($cb());
var_dump($cb2());
echo "Testing with scope as string", "\n";
$cb = $ca->bindTo($b, 'B');
$cb2 = Closure::bind($ca, $b, 'B');
var_dump($cb());
var_dump($cb2());
$cb = $ca->bindTo($b, NULL);
var_dump($cb());
Result:
int(1)
Testing with scope given as object
int(21)
int(22)
Testing with scope as string
int(23)
int(24)
[*]
Added short array syntax. Makes PHP code more readable and maintainable.
$a = [1, 2, 3];
$b = ['foo' => 'orange', 'bar' => 'apple', 'baz' => 'lemon'];
[*]
Added binary value format. Now it’s possible to use binary values directly in the PHP code:
$x = 0b001110;
echo $x;
[*]
Added support for Class::{expr}() syntax. Makes PHP more flexible, when calling class/object methods.
$method = 'method';
$test = new Test();
$test->method();
$test->$method();
$test->{'method'}();
Test::method();
Test::$method();
Test::{'method'}();
Result:
method
method
method
method
method
method
[*]
Added support for Traits. A Trait is intended to reduce some limitations of single inheritance by enabling a developer to reuse sets of methods freely in several independent classes living in different class hierarchies.
class Base {
public function sayHello() {
echo 'Hello ';
}
}
trait SayWorld {
public function sayHello() {
parent::sayHello();
echo 'World!';
}
}
class MyHelloWorld extends Base {
use SayWorld;
}
$o = new MyHelloWorld();
$o->sayHello();
Result:
Hello World!
[*]
Added closure $this support back. Now you have an access to every object property (be it public or not).
class A {
private $value = 1;
function firstGetter($name) {
return function() use ($name) {
return $this->$name;
};
}
function secondGetter() {
return function($name){
return $this->$name;
};
}
}
$a = new A();
$firstGetter = $a->firstGetter('value');
echo $firstGetter();
$secondGetter = $a->secondGetter();
echo $secondGetter('value');
Result:
1
1
[*]
Added array dereferencing support. Provides the implementation of array dereferencing of method/function return.
function fruit () {
return array('a' => 'apple', 'b' => 'banana');
}
echo fruit()['a'];
Result:
apple
[*]
Added indirect method call through array. Now $foo() also works in the cases where $foo is a callable array or Closure object.
class Hello {
static public function world($x) {
echo "Hello, $x\n";
}
}
function helloWorld($x) {
echo "Hello, $x\n";
}
$callbacks = array(
array('Hello', 'world'),
function ($x) { echo "Hello, $x\n"; },
'helloWorld'
);
foreach ($callbacks as $k => $callback) {
if (is_callable($callback)) {
$callback($k);
}
}
Result:
Hello, 0
Hello, 1
Hello, 2
[*]
Changed $GLOBALS into a JIT autoglobal. $GLOBALS array is initialized only if it’s used. This is a performance/memory optimization, it can however break some of the existing scripts or opcode caches.
[*]
Improved performance of @ (silence) operator. This can speed up PHP scripts which rely heavily on a silence operator, for example:
$x = @file_get_contents('/etc/passwd');
echo $x;
[*]
Added multibyte support by default. Previously php had to be compiled with –enable-zend-multibyte. Now it can be enabled or disabled through zend.multibyte directive in php.ini.
[*]
Added built-in web server that is intended for testing purpose. The following command will open a web server on the port 8000.
php -S localhost:8000
[*]Lots of performance and memory usage improvements
Removed major PHP features
[*]
Removed break/continue $var syntax. You can no longer use variable to tell PHP how many levels of enclosing loops it should skip to the end of.
[*]
Removed safe mode and all related ini options. Functionality described in this article and marked as depreciated in PHP 5.3 has now been removed
[*]
Removed register_globals and register_long_arrays ini options. If enabled, register_globals injected PHP scripts with all sorts of variables, like request variables from HTML forms or values from GET requests. Now, every request/environment variable must be fetched from an appropriate PHP array.
[*]
Removed allow_call_time_pass_reference option. Passing arguments by reference at function call time was deprecated for code-cleanliness reasons. A function can modify its arguments in an undocumented way if it didn’t declare that the argument shall be passed by reference. To prevent side-effects it’s better to specify which arguments are passed by reference in the function declaration only.
For a full list of changes in PHP 5.4, see the ChangeLog. For source downloads please visit php.net QAT downloads page, Windows binaries can be found here.
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