sorry for the late reply.
My time for working on/with LilyPond is eaten up by a large amount of
non-LilyPond projects and problems those days.
e.g.: Yesterday a tree in my garden toppled down on my neighbour's house.
(@David Kastrup: An own garden isn't a pleasure all the time.)
Eek! I'm sorry to hear this! I hope everyone is OK and that the damage isn't too serious.
But I wish to express my deepest gratefulness for your effort working on this.
You're very welcome!
Perhaps you noticed my posts on -devel about new barlines.
Yes--very impressive! And I love the "barline art" in the example file--it's clear you can do anything imaginable with those functions. (Music will just have to catch up to those notations there :) )
I haven't replied yet because I'd like to have something meaningful to say about usability, which is one intent of the current conversation (and not Scheme).
There you
can find a `make-dashed-bar-line'-definition very close to
`make-dashed-system-start-bar'. It was very difficult to develop it so
far, but your idea for the dashed-stems gave my the essential push for
a first, more or less successful try.
Because there are small but noticeable shifts of the dashes depending
on global-staff-size and/or the distances of the staffs, I'm not
really happy with that definition.
So any improvement for the dashed SystemStartBar would be of great
help for the barline-project.
My own attempts were not succesful so far. :(
I'll give it another look, but I can't make any promises...
Best,
David