Hello,
even today source code needs to be printed (to paper, to PDF...). So for a given font and font size there is a maximum number of characters per line that can be printed without forcing a line break.
Accordingly, I have arranged my source code that none of the lines exceeds this limit. I would consider it convenient to have a faint grey vertical line indicating this limit. So I suggest adding a 'ruler' with user settable vertical guides.
Thanks for consideration.
