Re: Looking at function

[Dmitry Gutov]

Hi Juri,

Sorry for the abysmal rate of replies here. isearch is really hard to 
fit in my head.

On 12.07.2022 10:50, Juri Linkov wrote:
> > > > Do we have a clear understanding of the idea behind this looking-at call?
> > > >
> > > > The comment says:
> > > >
> > > >           ;; Otherwise, if matching a regular expression, do the next
> > > >           ;; match now, since the replacement for this match may
> > > >           ;; affect whether the next match is adjacent to this one.
> > > >           ;; If that match is empty, don't use it.
> > > >
> > > > What happens if there are multiple adjacent matches in a row, not just 2?
> > > > I suppose the replacement could be performed for the first one, then the
> > > > next one is "popped" becoming the current and looking-at is called again
> > > > near its end?
>
> Actually, this is how it worked until now.
>
> > > > If so, perhaps a good alternative is to stop caring about whether those
> > > > matches are adjacent and always store the latest two matches, whether they
> > > > are next to each other or not.
>
> And this is how it's implemented by the patches in bug#14013 and bug#53758.

Sounds good, then. So this is a workable solution?

Or have you come across some pitfalls?

> > > The sole purpose of this "do the next match now" hack
> > > is to handle a special use case that is tested
> > > in test/lisp/replace-tests.el:
> > >       ;; Test case from commit 5632eb272c7
> > >       ("a a a " "C-M-% \\ba SPC RET c RET !" "ccc") ; not "ca c"
> > >       ;; Test case from commit 5632eb272c7
> > >       ("a a a " "\\ba " "c" nil t nil nil nil nil nil nil nil "ccc") ; not "ca 
> > > c"
> >
> > All right. So it seems the idea of keeping references to the two latest can
> > work.
> >
> > No idea how big the changes will have to be, though.
>
> Shouldn't keeping only one reference be sufficient?

By "two references" I meant the current one and the next one. Seems like 
the necessary minimum.