Until now, we have only seen ways to refer classes down the hierarchy. This chapter explains how you can go up the hierarchy...
At any time, you can refer to the parent class (I.e. the one of which you are a child) using that @parent symbol. For instance, refering to @parent.titi will look for a child named @titi in your parent class.
Suppose you are in a class very deep in the hierarchy, and you need to access some very
high level class.
For instance, you have a huge Amool class that describes your latest program, and deep in the gui-description, there is a little label that shows the version number of the program (in an 'about' window, for instance). This information is to be found in a direct child of the program named @versionNumber ...
If you know how many levels you must creep up, then you can do something like:
But this is not very elegant, you might make a mistake counting the levels, and you won't know where you go when re-reading your code...
This is were the tick-notation comes in.
Your program has a super class named @program. So you can ask Amool to go up until
it finds a subclass of @application. This is made putting a tick (') before the symbol
application, like this:
This means that, first the compiler will go from parent to parent, until it finds one that is named application or has a superclass named application