make id selectable by parent
Also consider inputs in componentRefs for generated methods.
Also generate value setters in form for input components
generated classes implement ChangesChildHtmlId if parent is null
move generateChangeChildHtmlId to parent
add and use validatedInput component
adjust to two-arg component constructor
Javadoc
Add documentation for parsing source files and generating the target
components.
add one further design objective
Document extra attribute behavior