Subject: Feature request: making occur obey isearch-filter-predicate

From: Gabriele Nicolardi <[email-masked]>
Date: Mon, 4 Mar 2024 12:44:48 +0100

Hi,

I’d like occur to obey to |isearch-filter-predicate| like query-replace* 
and |isearch*| commands.

This is an example of what I do:

|(defmacro with-ifp-predicates (PREDICATES &rest body) "Allows assigning 
a list of predicates to the variable `isearch-filter-predicate'. |

Below is an example of usage:

|(with-ifp-predicates '(skip-maths skip-comments) (query-replace \"foo\" 
\"bar\" nil (point-min) (point-max)))" (declare (indent 1)) `(let 
((isearch-filter-predicate isearch-filter-predicate)) (mapc (lambda 
(predicate) (add-function :before-while isearch-filter-predicate 
predicate)) ,PREDICATES) ,@body)) |

(I always use let-binding for operations that involve 
|isearch-filter-predicate|.)

In some cases, I would like to have something like this:

|(with-ifp-predicates '(predicate1 predicate2) (save-window-excursion 
(occur "foo") (query-replace \"foo\" \"bar\" nil (point-min) (point-max)))) |

with |occur| showing me only the strings that match the active predicates.

I wrote a mail to [email-masked] and I have verified that others 
also believe that this solution would be helpful and consistent with the 
functioning of some other functions defined in |replace.el|.

I’d also like to add this feature to the |how-many| function.

I already wrote this modified version (Emacs 29.2):

|(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 (search-forward-regexp 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")) (save-excursion 
(if rstart (if rend (progn (goto-char (min rstart rend)) (setq rend (max 
rstart rend))) (goto-char rstart) (setq rend (point-max))) (if (and 
interactive (use-region-p)) (setq rstart (region-beginning) rend 
(region-end)) (setq rstart (point) rend (point-max))) (goto-char 
rstart)) (let ((count 0) (case-fold-search (if (and case-fold-search 
search-upper-case) (isearch-no-upper-case-p regexp t) 
case-fold-search))) (while (and (< (point) rend) (re-search-forward-ifp 
regexp rend t)) ;; Ensure forward progress on zero-length matches like 
"^$". (when (and (= (match-beginning 0) (match-end 0)) (not (eobp))) 
(forward-char 1)) (setq count (1+ count))) (when interactive (message 
(ngettext "%d occurrence" "%d occurrences" count) count)) count))) 
(defalias 'count-matches-ifp 'how-many-ifp) |

Best regards,

Gabriele Nicolardi

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