Add multiple predicates to isearch-filter-predicate

Question

I wrote a set of predicates to filter matches in my ìsearch-* and query-replace* routines. I also wrote a macro to bind the isearch-filter-predicate variable to multiple predicates:

(defmacro with-ifp-predicates (PREDICATES &rest body)
  (declare (indent 1))
  `(let ((isearch-filter-predicate isearch-filter-predicate))
     (mapcar (lambda (x)
               (add-function :before-while isearch-filter-predicate x))
             ,PREDICATES)
     ,@body))

I use it in my code in this way:

(with-ifp-predicates '(skip-maths skip-comments)
  (query-replace "foo" "bar" nil (point-min) (point-max)))

I tested it and it seems to work but if I enter recursive-edit (C-r) and look at the value (C-h v) of the isearch-filter-predicate variable, I get this:

Is it normal? Is it caused by the :before-while? I chose it because I need a match to be skipped if just one of the predicats is satisfied.

Yes, it's normal. `add-function` generates those objects (which are byte-compiled-functions). In Emacs-26, you should see it displayed in a slightly more user-friendly way which would make it clear that it's an advice. — Stefan, Mar 13 '19 at 21:13

Drew · Accepted Answer · 2019-03-13T16:56:09.103

Yes, it's normal. The code is byte-compiled on the fly. See nadvice.el (advice-p, for example).

Because of this it can help to give a piece of advice a user-friendly name, which can kind of describe it.

FWIW, you might want to take a look at the dynamic Isearch filtering available with Isearch+. It gives you easy ways to add, combine, and remove Isearch filter predicates, either interactively or with code. I think it gives you a generalization of what you're doing now.

With respect to describing (at least naming) Isearch filter predicates:

You can name each predicate you activate (add) dynamically.
The names of the active predicates, and their order, can be shown in the Isearch prompt, so you can tell what filtering is being used.
You can also name the current suite of filter predicates, creating a named predicate that does the same thing. You can use that name to reuse the suite later or to easily remove it as the current predicate. See function isearch-defun-filter-predicate.

BTW - I'm glad to see someone taking an interest in using Isearch filtering, and in a flexible way. In vanilla Emacs it is so far used rarely, and only with hard-coded filters for a few particular contexts.

Thank you for the suggestions. I will study them carefully. This tool is proving to be very powerful in my work as a LaTeX typesetter, eliminating false positives from my `query-replace` routines and saving me a lot of time and mental energy. — Gabriele Nicolardi, Mar 13 '19 at 18:26

Add multiple predicates to isearch-filter-predicate

1 Answers1