Re: [Evolution] Long standing feature request (Undo operation)

[Pete Biggs <pete biggs org uk>]

> > Yes, it might be a useful thing and I might use it once or twice a
> > year, but I can see that to do it properly it would have to be built
> > into every operation and that is a massive task and something that
> > affects the whole of the gui codebase I presume - possibly even the
> > other backend components (if, in between deleting and undoing,
> > another
> > client expunges, then that needs to be handled and involves the
> > backends).
> >
> > I don't think it's as easy as some of the bug comments seem to think.
>
> That's disappointing, but understandable. Do you think the difficulty
> of implementing this is unique to Evolution's design, or is it just the
> way things are in general? I only ask because of the prevalence of this
> feature in other email clients I've used.
I suspect it's something that is "trivial" if it's designed into the
application from the beginning, but distinctly non-trivial to bolt on
afterwards. What I mean is that if it's something that is an intrinsic
part of the application, then whenever a new function is implemented,
some thought is put into the do-undo-redo process, and the way a
function is coded may well be determined by the undo requirements.
However, to retrofit it, that process has to be gone through for
everything - someone has to go through and analyse the code for every
function and action and work out how to do the undo, and it's not
unimaginable that a whole action will have to be re-coded just to
accommodate the requirements of the undo.

P.