I have been able to get whitespace-mode to display dots for leading spaces.
But I want to specially display each sequence of 2 leading spaces, with maybe a vertical bar.
Possible?
Maybe not with whitespace-mode?
As a separate question, how do I get whitespace-mode to display only leading spaces as middle-dot?
I have
whitespace-space-regexp "\\(^ +\\)"
...but that seems only to apply to the FACE used, not to the character substitution.
I've been fiddling with this for 20 minutes. I'm amazed that I still have not cracked this. Doesn't everyone want something like this?
vline.el
and the libraries that build upon / modify that library. I am working on feature requests 17684 and 22873 in my spare time, but I am probably a year or two (or more) away from perfecting them. [It just depends upon how spare time I have, combined with motivation ... The next patch proof concept will probably be available in about a month or so ...] Fill-column-indicator by Alp Aker may also be of interest to you -- it an be tweaked ...