Re: window-configurations and marks

["Andreas Röhler" <andreas.roehler@online.de>]

On 24.04.2014 15:15, Stefan Monnier wrote:
>
> A lot of code assumes that "mark-active non-nil implies that (mark)
> points somewhere", and I think it's a reasonable assumption.
>
> But occasionally this property is invalid.  One place I found where
> it can be invalidated is in set-window-configuration because
> window-configurations keep a copy of the mark, which is hence reset by
> set-window-configuration without paying attention to its connection to
> mark-active.
>
> I just installed a patch which changes set-window-configuration so as to
> call deactivate-mark when mark-active is non-nil and we set the mark to
> point nowhere.  But I don't like this patch:
> - I don't like to idea of running arbitrary Elisp code from the middle of
>    set-window-configuration.
> - It calls for calling activate-mark in the reverse case.
> - It's done "per-window" whereas the mark is "per-buffer".
>
> So, I'm really thinking that the better fix is to change
> set-window-configuration such that it does not touch the mark (which
> really doesn't have anything to do with windows or
> window-configurations, and indeed window-state doesn't include
> information about the mark).
>
> Any objection?
>
>
>          Stefan
>
>

Hi Stefan,

can't object at this point, as IMO the basics are confused to such an extend, these and other quirks are to expect.
Remember related matter being discussed around "interactive-p".

Best way is to clean up the core-functions.

For example have a look at "mark". Its docstring says:

"Return this buffer's mark value as integer, or nil if never set.

In Transient Mark mode, this function signals an error if
the mark is not active.  However, if `mark-even-if-inactive' is non-nil,
or the argument FORCE is non-nil, it disregards whether the mark
is active, and returns an integer or nil in the usual way."

IMO only the first line/feature is reasonable.
The remaining stuff belongs to commands making use of it, not here - nil or point is all needed.

Just an example. Cleaning that stuff up would save a lot of time and bugs later on.

Cheers,

Andreas