[Oberon] SystemV - Viewer Scroll

[Jörg Straube]

> Interesting, line brakes are kept in `Line' list that is built on the
> fly when line is displayed `DisplayLine'.

Correct. Please remember: this „Line“ data structure is only built for the visible lines in the frame not for the whole text! That is important to understand...

Try to find out, what the difference of Show (display content around an arbitrary position pos) and Modify (display the current content in a smaller or larger frame) is in respect to this internal Line data structure.

Ask yourself
- What Lines are built/known already?
- What Lines have to be built/found?
- How could I find/build missing Lines?

For backward scrolling, there are indeed other strategies thinkable to find line breaks compared to the current implementation.

Jörg