This is the base class for sequences within an XGEN document.
A sequence is a container that can hold one or more nodes within an XGEN document. A sequence does the following:
- optionally Generates one or more lines of code before processing its children.
- Loops over the child nodes within the sequence and asks each one to generate code in turn.
- optionally Generates one or more lines of code after processing its children.
Note that a subclass can prevent its child nodes from being processed by setting the