>If this can still be implemented in userland you don't need logic integrated
>at low level
Afaik it cannot be implemented in userland today.
The closest you can get today is to use reference hacks, which
introduce side-effects, like if you do
function blank(&$value){...}
blank($_POST['foo'])
and foo doesn't exist, the & ref will *create* foo with null, like
var_dump($_POST); // array(0) {}
blank($_POST['foo']);
var_dump($_POST); // array(1) {["foo"]=>NULL}
But maybe we could make it possible like
function blank(#[\AllowUndeclared] $value){...}
var_dump($_POST); // array(0) {}
blank($_POST['foo']);
var_dump($_POST); // array(0) {}
