why this method is implemented this way?

[navidhasanitabar]

framework/src/Illuminate/Container/Container.php

Line 1285 in 7966b9b

public function getAlias($abstract)

hi guys;
i have a question; why this method is implemented in this way? why it's recursive? i don't get it;

 isset($this->aliases[$abstract])
                    ? $this->getAlias($this->aliases[$abstract]) : $abstract;   // ===why-not-this?====> $this->aliases[$abstract] : $abstract