Re: Re: [EXPERIMENTAL PATCH] Extending Isearch-repeat-forward/backward to support a prefix argument

[gideon . stupp]

So it seems that the support for negative arguments will be best effort anyway. 
Ok, I will make sure the counting is done right. Also I believe that
when C-- C-1 isearch-forward is pressed the user expects to stay in isearch-forward and not switch to isearch-backward so I will add another call to isearch-forward just to change the direction. Not pretty but should do the job.

Thanks, gideon.

On , Juri Linkov <address@hidden> wrote:
> > Thank you for your comments Juri.  Do you have a thought on how to
> 
> > implement this functionality as a package the way Stefan asked for?
> 
> 
> 
> Adding a new count argument to `isearch-repeat-forward' is a pretty
> 
> unobtrusive change and is standard Emacs practice.  But if you want
> 
> to do fancy stuff with hint display then you could add a hook to
> 
> `isearch-lazy-highlight-update' and implement fancy features in a separate
> 
> package whose functionality is added by the hook.
> 
> 
> 
> > Negative arguments in particular seem to be challenging. Right now I
> 
> > implemented negative argument navigation by calling isearch-repeat with the
> 
> > opposite functionality but that has all kinds of odd effects.
> 
> > For example the search message changes, C-- C-1 isearch-forward does
> 
> > not go back one matched string but rather just switches to
> 
> > isearch-backward and so on.
> 
> 
> 
> Then you need to take into account this situation and to add 1 to the
> 
> counter when isearch-forward switches to isearch-backward with C-- C-1.
> 
> 
> 
> > I did implement visual hints for the negative arguments because that
> 
> > would require changing the way lazy highlight works significantly
> 
> > (lazy-highlight loop wraps around back to the first line and at that
> 
> > point you can't know the negative argument for the current match).
> 
> 
> 
> There are other problems with negative arguments: sometimes backward
> 
> regexp search finds more matches than forward regexp search.
> 
> For instance, trying to search a regexp like "a+" forward on a string
> 
> like "aaa" finds all occurrences of "aaa" as one match, but backward
> 
> regexp search matches every "a" individually.
>