compare-windows should allow backwards comparing

compare-windows should allow backwards comparing

[Dan Jacobson]

compare-windows should allow backwards comparing, i.e., marching
upwards, not just always downwards.

Re: compare-windows should allow backwards comparing

[Juri Linkov]

Dan Jacobson <jidanni@jidanni.org> writes:
> compare-windows should allow backwards comparing, i.e., marching
> upwards, not just always downwards.

Great idea!  I often need this too.  Like searching for a text with
C-s needs the reverse key C-r to return to the previous matches,
searching for the differences needs the reverse function too.

And it seems it is easily implementable: just changing `forward' to
`backward' in some function names and changing the sign in some
arithmetic operations.

But what would be the best UI for this?  `compare-windows' already
has a prefix arg `ignore-whitespace', so using a prefix key to
switch the direction is not possible.  Maybe creating the new
command `compare-windows-backward' is enough?

-- 
Juri Linkov
http://www.jurta.org/emacs/

throwing away future possibilities via "nil or not nil"

[Dan Jacobson]

Juri> `compare-windows' already has a prefix arg `ignore-whitespace',
Juri> so using a prefix key to switch the direction is not possible.

Just curious, are things like that examples of where future extensions
are not anticipated, like specifying "nil or not nil" and thus
throwing away future other possibilities? (So less elegant
alternatives must be used.)