Anonymous classes

Support for anonymous classes was added in PHP 7. Anonymous classes are useful when simple, one-off objects need to be created.

<?php

// Pre PHP 7 code
class Logger
{
    public function 
log($msg)
    {
        echo 
$msg;
    }
}

$util->setLogger(new Logger());

// PHP 7+ code
$util->setLogger(new class {
    public function 
log($msg)
    {
        echo 
$msg;
    }
});

They can pass arguments through to their constructors, extend other classes, implement interfaces, and use traits just like a normal class can:

<?php

class SomeClass {}
interface 
SomeInterface {}
trait SomeTrait {}

var_dump(new class(10) extends SomeClass implements SomeInterface {
    private 
$num;

    public function 
__construct($num)
    {
        
$this->num $num;
    }

    use 
SomeTrait;
});

Наведений вище приклад виведе:

object(class@anonymous)#1 (1) {
  ["Command line code0x104c5b612":"class@anonymous":private]=>
  int(10)
}

Nesting an anonymous class within another class does not give it access to any private or protected methods or properties of that outer class. In order to use the outer class' protected properties or methods, the anonymous class can extend the outer class. To use the private or protected properties of the outer class in the anonymous class, they must be passed through its constructor:

<?php

class Outer
{
    private 
$prop 1;
    protected 
$prop2 2;

    protected function 
func1()
    {
        return 
3;
    }

    public function 
func2()
    {
        return new class(
$this->prop) extends Outer {
            private 
$prop3;

            public function 
__construct($prop)
            {
                
$this->prop3 $prop;
            }

            public function 
func3()
            {
                return 
$this->prop2 $this->prop3 $this->func1();
            }
        };
    }
}

echo (new 
Outer)->func2()->func3();

Наведений вище приклад виведе:

6
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User Contributed Notes 9 notes

up
40
Anonymous
8 years ago
Below three examples describe anonymous class with very simple and basic but quite understandable example

<?php
// First way - anonymous class assigned directly to variable
$ano_class_obj = new class{
    public
$prop1 = 'hello';
    public
$prop2 = 754;
    const
SETT = 'some config';

    public function
getValue()
    {
       
// do some operation
       
return 'some returned value';
    }

    public function
getValueWithArgu($str)
    {
       
// do some operation
       
return 'returned value is '.$str;
    }
};

echo
"\n";

var_dump($ano_class_obj);
echo
"\n";

echo
$ano_class_obj->prop1;
echo
"\n";

echo
$ano_class_obj->prop2;
echo
"\n";

echo
$ano_class_obj::SETT;
echo
"\n";

echo
$ano_class_obj->getValue();
echo
"\n";

echo
$ano_class_obj->getValueWithArgu('OOP');
echo
"\n";

echo
"\n";

// Second way - anonymous class assigned to variable via defined function
$ano_class_obj_with_func = ano_func();

function
ano_func()
{
    return new class {
        public
$prop1 = 'hello';
        public
$prop2 = 754;
        const
SETT = 'some config';

        public function
getValue()
        {
           
// do some operation
           
return 'some returned value';
        }

        public function
getValueWithArgu($str)
        {
           
// do some operation
           
return 'returned value is '.$str;
        }
    };
}

echo
"\n";

var_dump($ano_class_obj_with_func);
echo
"\n";

echo
$ano_class_obj_with_func->prop1;
echo
"\n";

echo
$ano_class_obj_with_func->prop2;
echo
"\n";

echo
$ano_class_obj_with_func::SETT;
echo
"\n";

echo
$ano_class_obj_with_func->getValue();
echo
"\n";

echo
$ano_class_obj_with_func->getValueWithArgu('OOP');
echo
"\n";

echo
"\n";

// Third way - passing argument to anonymous class via constructors
$arg = 1; // we got it by some operation
$config = [2, false]; // we got it by some operation
$ano_class_obj_with_arg = ano_func_with_arg($arg, $config);

function
ano_func_with_arg($arg, $config)
{
    return new class(
$arg, $config) {
        public
$prop1 = 'hello';
        public
$prop2 = 754;
        public
$prop3, $config;
        const
SETT = 'some config';

        public function
__construct($arg, $config)
        {
           
$this->prop3 = $arg;
           
$this->config =$config;
        }

        public function
getValue()
        {
           
// do some operation
           
return 'some returned value';
        }

        public function
getValueWithArgu($str)
        {
           
// do some operation
           
return 'returned value is '.$str;
        }
    };
}

echo
"\n";

var_dump($ano_class_obj_with_arg);
echo
"\n";

echo
$ano_class_obj_with_arg->prop1;
echo
"\n";

echo
$ano_class_obj_with_arg->prop2;
echo
"\n";

echo
$ano_class_obj_with_arg::SETT;
echo
"\n";

echo
$ano_class_obj_with_arg->getValue();
echo
"\n";

echo
$ano_class_obj_with_arg->getValueWithArgu('OOP');
echo
"\n";

echo
"\n";
up
14
ytubeshareit at gmail dot com
6 years ago
Anonymous classes are syntax sugar that may appear deceiving to some.
The 'anonymous' class is still parsed into the global scope, where it is auto assigned a name, and every time the class is needed, that global class definition is used.  Example to illustrate....

The anonymous class version...
<?php

function return_anon(){
    return new class{
         public static
$str="foo"
    };
}
$test=return_anon();
echo
$test::$str; //ouputs foo

//we can still access the 'anon' class directly in the global scope!
$another=get_class($test); //get the auto assigned name
echo $another::$str;    //outputs foo
?>

The above is functionally the same as doing this....
<?php
class I_named_this_one{
    public static
$str="foo";
}
function
return_not_anon(){
    return
'I_named_this_one';
}
$clzz=return_not_anon();//get class name
echo $clzz::$str;
?>
up
7
sebastian.wasser at gmail
5 years ago
I wanted to share my findings on static properties of anonymous classes.

So, given an anonymous class' object generating function like this:

<?php
function nc () {
    return new class {
        public static
$prop = [];
    };
}
?>

Getting a new object and changing the static property:

<?php
$a
= nc();
$a::$prop[] = 'a';

var_dump($a::$prop);
// array(1) {
//   [0] =>
//   string(1) "a"
// }
?>

Now getting another object and changing the static property will change the original one, meaning that the static property is truly static:

<?php
$b
= nc();
$b::$prop[] = 'b';

var_dump($b::$prop); // Same as var_dump($a::$prop);
// array(2) {
//   [0] =>
//   string(1) "a"
//   [1] =>
//   string(1) "b"
// }

assert($a::$prop === $b::$prop); // true
?>
up
4
j.m \ jamesweb \ ca
6 years ago
/* I like the idea of OneShot classes.
Thanks to that Anonymous bro\sist for precising  
new class( $a, $b )
¯¯¯¯¯¯¯¯¯

If you are looking for "Delayed OneShot Anonymous Classes" for any reason (like the reason: loading files in a readable manner while not using autoload), it would probably look something like this; */

$u = function()use(&$u){
    $u = new class{private $name = 'Utils';};
};

$w = function(&$rewrite)use(&$w){
    $w = null;
    $rewrite = new class{private $name = 'DataUtils';};
};

// Usage;
var_dump(
    array(
        'Delayed',
        '( Self Destructive )',
        'Anonymous Class Creation',
        array(
            'Before ( $u )' => $u,
            'Running ( $u() )' => $u(),
            'After ( $u )' => $u,
        ),
        0,0,
        0,0,
        0,0,
        'Delayed',
        '( Overwriting && Self Destructive )',
        'Anonymous Class Creation',
        array(
            'Before ( $w )' => $w,
            'Running ( $w($u) )' => $w($u),
            'After ( $w )' => $w,
            'After ( $u )' => $u
        )
    )
);

// btw : oh shoot I failed a spam challenge
up
1
joey
4 years ago
The only way to type hint this would appear to be as object.

If you need multiple instances of an anonymous class in a function you can use:

$class = function(string $arg):object {
    return new class($arg) {
        public function __construct(string $arg) {
            $this->ow = $arg;
        }
    };
};

Though for the sake of structure it's ill advised to do something like this outside of a single scope or that's used across multiple files. If you class is only used in one scope however then it's probably not a code mess problem.
up
0
razvan_bc at yahoo dot com
4 years ago
you can try these

<?php

$oracle
=&$_['nice_php'];
$_['nice_php']=(function(){
    return new class{
        public static function
say($msg){
            echo
$msg;
        }

        public static function
sp(){
            echo
self::say(' ');
        }

    };
});

/*
$_['nice_php']()::say('Hello');
$_['nice_php']()::sp();
$_['nice_php']()::say('World');
$_['nice_php']()::sp();
$_['nice_php']()::say('!');
//almost the same code bottom
*/

$oracle()::say('Hello');
$oracle()::sp();
$oracle()::say('World');
$oracle()::sp();
$oracle()::say('!');
?>
up
-2
piotr at maslosoft dot com
6 years ago
Please note that class name returned by `get_class` might contain null bytes, as is the case in my version of PHP (7.1.4).

Name will change when class starting line or it's body is changed.

Yes, name is implementation detail that should not be relied upon, but in some rare use cases it is required (annotating anonymous class).
up
-12
solobot
6 years ago
eval() is workaround for generating multiple anonymous classes with static properties in loop
<?php
public function generateClassMap()
    {
        foreach (
$this->classMap as $tableName => $class)
        {
           
$c = null;
            eval(
'$c = new class extends \common\MyStaticClass {
                public static $tableName;
                public static function tableName()
                {
                    return static::$tableName;
                }
            };'
);
           
$c::$tableName = $this->replicationPrefix.$tableName;
           
$this->classMap[$tableName] = $c;

        }
    }
?>
thus every class will have its own $tableName instead of common ancestor.
up
-19
primipilus13 at gmail dot com
7 years ago
<?php

// using constructor and extends in anonymous class 

class A
{
    private
$name;   

    public function
__construct($name)
    {
       
$this->name = $name;
    }

    public function
getName()
    {
        return
$this->name;
    }
}

$b = new class('anonymous') extends A
{
    public function
getName()
    {
        return
parent::getName() . ' class';
    }
};

echo
$b->getName(), PHP_EOL;

// result: anonimous class
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