Re: Simple isearch concerns

[Ergus]

Hi Juri:

Sorry to bother. But I don't understand much of this email. Is this documented
somewhere? Could you add a simple use case example for a simple user
or dumb lisper like me?


On Wed, Apr 07, 2021 at 11:12:12PM +0300, Juri Linkov wrote:
> If you want a separate option, this is fine.  But then there is no need
> to duplicate the key remapping feature.  To make the new feature more powerful,
> you could attach to command symbol properties a function that
> defines where to move point before searching the next match.
>
> This is similar to how isearch-yank-internal funcalls its arg 'jumpform',
> and how its callers like isearch-yank-char uses
>
>  (lambda () (forward-char arg) (point))
>
> or isearch-yank-word uses
>
>  (lambda () (forward-word arg) (point))
>
> to define where to move point before using it as the buffer position.
>
> So command symbol properties could be defined using the same logic:
>
>  (put 'beginning-of-buffer 'isearch-match-scroll 'beginning-of-buffer)
>  (put 'end-of-buffer 'isearch-match-scroll 'end-of-buffer)
>  (put 'scroll-up-command 'isearch-match-scroll (lambda () (goto-char 
> (window-end))))
>  (put 'scroll-down-command 'isearch-match-scroll (lambda () (goto-char 
> (window-start))))
>
> where the symbol property is called like (funcall 'beginning-of-buffer)
> before repeating the search.
>
> Then there is no need to add such ad-hoc commands as isearch-scroll-up
> and isearch-scroll-down.
>
> And instead of
>
>  (setq this-command (get this-command 'isearch-match-scroll))
>
> isearch-pre-command-hook could contain the same code
> that is currently duplicated in several commands:
>
>  (setq isearch-just-started t)
>  (goto-char (window-end))  ;; only this line needs to be
>                            ;; replaced with (funcall jumpform)
>  (isearch-repeat 'forward)
>
> Whereas it would be easy to handle more commands like below:

> Actually, the 'isearch-match-scroll' above doesn't do what is needed.
> It just goes to the next match, whereas the need was to go to the next line
> before searching for a new match.
>
> With the logic above, this is easy to define like:
>
>  (put 'next-line 'isearch-match-scroll (lambda () (forward-line 1)))