Re: The future of Follow Mode - a proposal.

[Stefan Monnier]

> Actually, vertical-motion completely breaks in that case.  I don't
> even see a way that will allow to solve that situation in principle,
> except in some very specific and restricted use cases.

Exactly.  E.g. the behavior of vertical-motion could be "made to work" in
the case where the motion is within the existing glyph matrices of the
relevant windows, tho even in that case there could be several possible
desirable behaviors depending on the intention behind the use of
vertical-motion.

> Which is why I strongly suggest to change Follow Mode so that it
> forces all of its windows be of the same width.

And in that case my Elisp hook approach should be usable (assuming it's
implementable ;-).

> With the current pixelwise control of window dimensions, this is easy.

Not sure about "easy" but yes.

> I think this will magically remove many of the problems that currently
> plague Follow Mode, and leave us with something we can reasonably easy
> to solve and maintain.

Sounds fine (and doable in Elisp).

> However, Alan disagrees, and insists on supporting windows of unequal
> width.

I think it might makes sense to allow the user to disable the "make all
follow-mode windows same-width" and just live with the corresponding
quirks, but I suspect that the amount of work needed to make follow-mode
work "100% correctly" for the mixed-width case is really large (it will
involve defining new primitives to replace vertical-motion, then
changing all users accordingly).  What's the expected use-case that
would justify such an effort?


        Stefan