Combine multiple Action/Condition into reusable Custom Action

Custom Action is a way to create a new Action by combining other Action and Condition together.

Custom Action is also just a list of Action/Condition similar to Job. But there are some differences:

1. Action within a Custom Action will run once and in order.
2. Custom Action doesn't really have a state. It can only access things in the Macro Scope
3. Unlike Job which is always active, Custom Action will run when call and end similar to other Action.
4. Custom Action can't run a Job but it can run other Custom Action.

You can run a Custom Action within another Custom Action.

Circular Reference occurs when a Custom Action at some point call itself again.

The classic A -> B -> C -> A. This will create a circular reference, the macro will get stuck in that loop until memory run out (also known as StackOverflow error).

Any circular reference will be removed (the whole chain just simply does nothing) to prevent error.