Apologies Eli, I missed this thread! On 28 December 2024 11:09:46 GMT, Eli Zaretskii wrote: >Ping! Ping! Ping! Divya, please respond. > >> Cc: monnier@iro.umontreal.ca, 74281@debbugs.gnu.org >> Date: Sat, 14 Dec 2024 11:34:40 +0200 >> From: Eli Zaretskii >> >> Ping! Ping! Divya, are you there? >> >> > Cc: 74281@debbugs.gnu.org >> > Date: Sat, 30 Nov 2024 11:51:49 +0200 >> > From: Eli Zaretskii >> > >> > Ping! Divya, could you please try Stefan's suggestions and report >> > back? >> > >> > > Cc: Divya Ranjan , 74281@debbugs.gnu.org >> > > From: Stefan Monnier >> > > Date: Thu, 14 Nov 2024 11:56:37 -0500 >> > > >> > > > Stefan, what tools do we have to investigate slowness related to >> > > > parse-partial-sexp? Or maybe you have suggestions for how to speed up >> > > > font-lock in this case? >> > > >> > > Hmm... `parse-partial-sexp` is normally expected to be fast, unless it >> > > has to scan a lot of text. >> > > >> > > > Here's the profile I get while moving with C-p through the above file: >> > > >> > > A stab in the dark, but maybe the relevant call is the one in: >> > > >> > > (state (if (or syntax-ppss-table >> > > (not font-lock--syntax-table-affects-ppss)) >> > > (syntax-ppss start) >> > > ;; If `syntax-ppss' doesn't have its own syntax-table and >> > > ;; we have installed our own syntax-table which >> > > ;; differs from the standard one in ways which affects PPSS, >> > > ;; then we can't use `syntax-ppss' since that would pollute >> > > ;; and be polluted by its cache. >> > > (parse-partial-sexp (point-min) start))) >> > > >> > > so the origin of the slowdown would be the (?#. "w 14") in the setting >> > > below in `scheme.el`: >> > > >> > > (setq font-lock-defaults >> > > '((scheme-font-lock-keywords >> > > scheme-font-lock-keywords-1 scheme-font-lock-keywords-2) >> > > nil t (("+-*/.<>=!?$%_&~^:" . "w") (?#. "w 14")) >> > > beginning-of-defun >> > > (font-lock-mark-block-function . mark-defun))) >> > > >> > > in which case, setting a `syntax-ppss-table` should fix the problem, tho >> > > we could also fix it by being more careful: AFAICT the purpose of this >> > > (?#. "w 14") is only to change the syntax of `#` from "prefix" to "word" >> > > without changing the comment-related flags, so it shouldn't cause >> > > `font-lock--syntax-table-affects-ppss` to be set. >> > > So, we could solve it by improving the code that sets >> > > `font-lock--syntax-table-affects-ppss`, as in the patch below. >> > > >> > > >> > > Stefan >> > > >> > > >> > > diff --git a/lisp/font-lock.el b/lisp/font-lock.el >> > > index 203131bfd5a..f6299920c0a 100644 >> > > --- a/lisp/font-lock.el >> > > +++ b/lisp/font-lock.el >> > > @@ -1955,14 +1955,15 @@ font-lock-set-defaults >> > > (dolist (char (if (numberp (car selem)) >> > > (list (car selem)) >> > > (mapcar #'identity (car selem)))) >> > > - (unless (memq (car (aref font-lock-syntax-table char)) >> > > - '(1 2 3)) ;"." "w" "_" >> > > - (setq font-lock--syntax-table-affects-ppss t)) >> > > - (modify-syntax-entry char syntax font-lock-syntax-table) >> > > - (unless (memq (car (aref font-lock-syntax-table char)) >> > > - '(1 2 3)) ;"." "w" "_" >> > > - (setq font-lock--syntax-table-affects-ppss t)) >> > > - )))) >> > > + (let ((old-syntax (aref font-lock-syntax-table char))) >> > > + (modify-syntax-entry char syntax font-lock-syntax-table) >> > > + (let ((new-syntax (aref font-lock-syntax-table char))) >> > > + (unless (and (equal (cdr old-syntax) (cdr new-syntax)) >> > > + (memq (logand (car old-syntax) 255) '(1 2 3 6)) >> > > + (memq (logand (car new-syntax) 255) '(1 2 3 6)) >> > > + (equal (ash (car old-syntax) -8) >> > > + (ash (car new-syntax) -8))) >> > > + (setq font-lock--syntax-table-affects-ppss t)))))))) >> > > ;; (nth 4 defaults) used to hold `font-lock-beginning-of-syntax-function', >> > > ;; but that was removed in 25.1, so if it's a cons cell, we assume that >> > > ;; it's part of the variable alist. >> > > >> > > >> > > >> > > >> > > >> > >> > >> > >> > >> >> >> >> > > > Divya Ranjan, Mathematics, Philosophy and Libre Software