What is the correspondent resource of a functions library in YII ?

Archives Yii 1.0.x Discussions
1

In a Prado Application I could have a TModule subclassing with my static library of functions to be used in anywhere that I would need.

How can I do the same in Yii ?

A book of functions (services) like I have mentioned, would be an inheritance of which Yii class?

TIA

MN

2

CApplicationComponent

3

And in a Yii fashion, where is the best subdir (of a yii app structure) to locate this kind of "services" (functions) library ?

TIA MN