I have a function that takes variadic arguments, that I obtain from func_get_args().
This function needs to call a constructor with those arguments. However, I don't know how to do it.
With call_user_func, you can call functions with an array of arguments, but how would you call a constructor from it? I can't just pass the array of arguments to it; it must believe I've called it "normally".
Thank you!
For PHP < 5.3 it's not easily doable without first creating an instance of the class with call_user_func_array. However with Reflection this is pretty trivial:
$reflection = new ReflectionClass( 'yourClassName' );
$instance = $reflection->newInstanceArgs( $yourArrayOfConstructorArguments );
ReflectionClass::newInstanceArgs is not new in PHP 5.3, we've had it around since 2006 when it was released with PHP 5.1.3. @byronh, is there anything in particular that you found not well explained or are you referring to the parts labeled as "undocumented"? (Feel free to email me, [email protected])
If for some reason you can not use ReflectionClass::newInstanceArgs here is another solution using eval():
function make_instance($class, $args) {
$arglist = array();
$i = 0;
foreach($args => &$v) {
$arglist[] = $n = '_arg_'.$i++;
$$n = &$v;
}
$arglist = '$'.implode(',$',$arglist);
eval("\$obj = new $class($arglist);");
return $obj;
}
$instance = make_instance('yourClassName', $yourArrayOfConstructorArguments);
Note that using this function enables you to pass arguments by reference to the constructor, which is not acceptable with ReflectionClass::newInstanceArgs.
eval? I've clearly stated at the beginning this is an alternative solution using eval
new SomeClass( ... [ 'arg1', 'arg2' ] );