Online PHP editor | output for vJ36M

@ 2014-10-09T17:16:10Z

<?php

class Foo
{
    private $bar = 'baz';

    public function getBar()
    {
        return $this->bar;
    }
}

// http://3v4l.org/pc6lo#v540
class ClassicLazyFoo extends Foo
{
    private $initialized = false;

    public function getBar()
    {
        $this->init();

        return parent::getBar();
    }

    private function init()
    {
        if ($this->initialized) { return; }

        \Closure::bind(function() {
            var_dump('lazy loading!');

            $this->bar = 'Loaded from DB!';
        }, $this, get_parent_class($this))->__invoke();
    }
}

// look ma: no method overrides!
class LazyPropertyLazyFoo extends Foo
{
    public function __construct()
    {
        \Closure::bind(function() {
            unset($this->bar);
        }, $this, get_parent_class($this))->__invoke();
    }

    // note that other accessors also need to be created for full functional completeness
    public function __get($name)
    {
        \Closure::bind(function() {
            var_dump('lazy loading!');

            $this->bar = 'Loaded from DB!';
        }, $this, get_parent_class($this))->__invoke();

        return \Closure::bind(function() use ($name) {
            return $this->$name;
        }, $this, get_parent_class($this))->__invoke();
    }
}

var_dump('Trying classic lazy-loading via method overrides:');

$classic = new ClassicLazyFoo();

var_dump($classic->getBar());
var_dump($classic->getBar());
var_dump($classic->getBar());

var_dump('Trying lazy-loading via undefined properties:');

$lazyProperty = new LazyPropertyLazyFoo();

var_dump($lazyProperty->getBar());
var_dump($lazyProperty->getBar());
var_dump($lazyProperty->getBar());

Output for 5.4.0 - 5.4.45, 5.5.24 - 5.5.35, 5.6.7 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.33, 7.2.17 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6: string(49) "Trying classic lazy-loading via method overrides:" string(13) "lazy loading!" string(15) "Loaded from DB!" string(13) "lazy loading!" string(15) "Loaded from DB!" string(13) "lazy loading!" string(15) "Loaded from DB!" string(45) "Trying lazy-loading via undefined properties:" string(13) "lazy loading!" string(15) "Loaded from DB!" string(15) "Loaded from DB!" string(15) "Loaded from DB!"
Output for 5.3.0 - 5.3.29: string(49) "Trying classic lazy-loading via method overrides:" Fatal error: Call to undefined method Closure::bind() in /in/vJ36M on line 29
Process exited with code 255.
Output for 5.1.0 - 5.1.6, 5.2.0 - 5.2.17: Warning: Unexpected character in input: '\' (ASCII=92) state=1 in /in/vJ36M on line 29 Parse error: syntax error, unexpected T_FUNCTION, expecting ')' in /in/vJ36M on line 29
Process exited with code 255.
Output for 5.0.0 - 5.0.5: Warning: Unexpected character in input: '\' (ASCII=92) state=1 in /in/vJ36M on line 29 Parse error: parse error, unexpected T_FUNCTION, expecting ')' in /in/vJ36M on line 29
Process exited with code 255.
Output for 4.4.2 - 4.4.9: Parse error: syntax error, unexpected T_STRING, expecting T_OLD_FUNCTION or T_FUNCTION or T_VAR or '}' in /in/vJ36M on line 5
Process exited with code 255.
Output for 4.3.0 - 4.3.1, 4.3.5 - 4.3.11, 4.4.0 - 4.4.1: Parse error: parse error, unexpected T_STRING, expecting T_OLD_FUNCTION or T_FUNCTION or T_VAR or '}' in /in/vJ36M on line 5
Process exited with code 255.
Output for 4.3.2 - 4.3.4: Parse error: parse error, expecting `T_OLD_FUNCTION' or `T_FUNCTION' or `T_VAR' or `'}'' in /in/vJ36M on line 5
Process exited with code 255.

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