Hello,
while translating the documentation (my question is not related to the translation though) I found the following statement (link: http://www.yiiframework.com/doc/guide/1.1/en/extension.create#action):
But neither IAction, nor CAction has this method. Now I’m curious, why? 
Actually I knew CAction didn’t have that method, but since the documentation refers to it, I think it should be clarified?
P.S. I know, if an interface has a method “function abc()” without params, then a class implementing this interface can’t define a method “function abc($a)” (will get “Declaration must be compatible…” error). In the case of using action classes it will be a problem (see action parameter binding). But the run() method can be put into the CAction class (CAction class methods call this method, but it’s not even defined!).