3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
$value = null; $executed = false; return function () use ($producer, & $value, & $executed) { if (!$executed) { $value = $producer(); $executed = true; } return $value; }; <?php class Connection {} class Context { public function get_instance(){ static $i; $i ?: $i = new Connection(); return $i; } } class A extends Context {} class B extends A {} class Context2 { protected $conn; public function __constructor() { $this->conn = new Connection(); // Should be lazily created but imagine we have once(). } public function get_instance(){ return $this->conn; } } class A2 extends Context2 {} class B2 extends A2 {} $a = new A(); $b = new B(); $a2 = new A2(); $b2 = new B2(); var_dump($a->get_instance()); var_dump($b->get_instance()); var_dump($a2->get_instance()); var_dump($b2->get_instance());
based on OYbWc
Output for 5.3.0 - 7.2.0
$value = null; $executed = false; return function () use ($producer, & $value, & $executed) { if (!$executed) { $value = $producer(); $executed = true; } return $value; }; object(Connection)#5 (0) { } object(Connection)#6 (0) { } NULL NULL
Output for 5.1.0 - 5.2.17
Parse error: syntax error, unexpected ':' in /in/asujT on line 19
Process exited with code 255.
Output for 5.0.0 - 5.0.5
Parse error: parse error, unexpected ':' in /in/asujT on line 19
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/asujT on line 17
Process exited with code 255.
Output for 4.3.0 - 4.3.1, 4.3.5 - 4.4.1
Parse error: parse error, unexpected T_STRING, expecting T_OLD_FUNCTION or T_FUNCTION or T_VAR or '}' in /in/asujT on line 17
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/asujT on line 17
Process exited with code 255.