src/Server.php
public function offsetSet($func, $callback)
    {
        $this->XRLFunctions[$func] = new \fpoirotte\XRL\CallableObject($callback);
    }
public function offsetSet($func, $callback)
    {
        $this->XRLFunctions[$func] = new \fpoirotte\XRL\CallableObject($callback);
    }
\copydoc fpoirotte::XRL::Server::__set()

This method is an alias for fpoirotte::XRL::Server::__set().