Re: Why don't `occur`, `search-forward*` and `string-match*` respect `isearch-filter-predicate`?

[Gabriele Nicolardi <gabriele@medialab.sissa.it>]

This code I wrote seems to work:

;; see https://emacs.stackexchange.com/a/80612/15606

(let ((re-search-forward-copy (symbol-function 're-search-forward)))
   (defun re-search-forward-ifp (REGEXP &optional BOUND NOERROR COUNT)
     "Modified version of `search-forward-regexp' that
     filters (skips) matches according to `isearch-filter-predicate'."

     (let ((POINT (point)))
       (catch 'filtered
         (while (funcall re-search-forward-copy REGEXP BOUND NOERROR COUNT)
           (let ((B (match-beginning 0))
                 (E (match-end 0)))
             (when (funcall isearch-filter-predicate B E)
               (throw 'filtered (point)))))
         (goto-char POINT)
         nil))))
(defalias 'search-forward-regexp-ifp 're-search-forward-ifp)

(defun how-many-ifp (regexp &optional rstart rend interactive)
   "Modified version of `how-many' that filters (skips) matches according to
`isearch-filter-predicate'."
   (interactive
    (keep-lines-read-args "How many matches for regexp"))
   (unwind-protect
       (progn
         (advice-add 're-search-forward :override #'re-search-forward-ifp)
         (how-many regexp rstart rend interactive))
     (advice-remove 're-search-forward #'re-search-forward-ifp)))
(defalias 'count-matches-ifp 'how-many-ifp)

(defun occur-ifp (regexp &optional nlines region)
   "Modified version of `occur' that filters (skips) matches according to
`isearch-filter-predicate'."
   (interactive
    (nconc (occur-read-primary-args)
           (and (use-region-p) (list (region-bounds)))))
   (unwind-protect
       (progn
         (advice-add 're-search-forward :override #'re-search-forward-ifp)
         (occur regexp nlines region))
     (advice-remove 're-search-forward #'re-search-forward-ifp)))

These are modified versions of re-search-forward, how-many and occur 
functions that obey to isearch-filter-pradicate but I am not entirely 
certain if I have written the code rigorously.

Perhaps they could be a starting point.