Re: Issues with japanese support

From: Ralf Angeli <[email protected]>
Subject: Re: Issues with japanese support
Date: Wed, 16 Feb 2005 10:28:48 +0100

> * Masayuki Ataka (2005-02-16) writes:
> 
> > Maybe we need a new variable for Emacs21 and XEmacs.
> >   (defvar LaTeX-word-across-newline
> >     (if (boundp 'word-across-newline) word-across-newline "\\c|"))
> 
> Although I have a `re-search-forward' phobia since we had these
> performance problems related to filling, I think this would be a
> pragmatic solution.  At least there is not much difference in
> execution time between the following two implementations (work only
> with Emacs):
> 
Let me name the code for convenience.

fill-cvs-emacs:
> (with-temp-buffer
>   (dotimes (i 100000)
>     (insert "\n\n"))
>   (goto-char (point-min))
>   (abs (- (prog1 (float-time (current-time))
> 	    (while (search-forward "\n" nil t)
> 	      (let ((prev (char-before (match-beginning 0)))
> 		    (next (following-char)))
> 		(when (or (aref (char-category-set next) ?|)
> 			  (aref (char-category-set prev) ?|))
> 		  (delete-char -1)))))
> 	  (float-time (current-time)))))

fill-replace:
> (with-temp-buffer
>   (dotimes (i 100000)
>     (insert "\n\n"))
>   (goto-char (point-min))
>   (abs (- (prog1 (float-time (current-time))
> 	    (while (re-search-forward "\\(\\c|\\)\n\\(\\c|\\)" nil t)
> 	      (replace-match "\\1\\2")))
> 	  (float-time (current-time)))))

And new code.

fill-skip-char:
(with-temp-buffer
  (dotimes (i 100000)
    (insert "\n\n"))
  (goto-char (point-min))
  (abs (- (prog1 (float-time (current-time))
	    (while (re-search-forward "\\(\\c|\\)\n\\(\\c|\\)" nil t)
	      (skip-chars-backward "^\n")
	      (delete-char -1)))
	  (float-time (current-time)))))

In my computer and Emacs-21.4, `fill-re-search' is faster
than `fill-cvs-emacs':
  (fill-cvs-emacs) 2.065401077270508
  (fill-replace)   1.1991240978240967
  (fill-skip-char) 0.9685571193695068
But, after byte-compile, `fill-cvs-emacs' becomes much
faster:
  (fill-cvs-emacs) 0.5713150501251221
  (fill-replace)   1.1394240856170654
  (fill-skip-char) 0.9528110027313232

Yes.  `re-search-forward' has a performance problem.
`fill-cvs-emacs' is the fastest.  `fill-skip-char' is better
than `re-search-forward'.  So, our new function will be...

(defun LaTeX-fill-delete-newlines (from to justify nosqueeze squeeze-after)
  ;; COMPATIBILITY for Emacs <= 22.1
  (if (fboundp 'fill-delete-newlines)
      (fill-delete-newlines from to justify nosqueeze squeeze-after)
    (if (featurep 'xemacs)
        (when (featurep 'mule)
          (goto-char from)
          (while (re-search-forward "\\(\\cj\\)\n\\(\\cj\\)" to t)
              (skip-chars-backward "^\n")
              (delete-char -1)))
      ;; This else-sentence was copied from the function `fill-delete-newlines'
      ;; in `fill.el' (CVS Emacs, 2005-02-17).
      (while (search-forward "\n" nil t)
        (let ((prev (char-before (match-beginning 0)))
              (next (following-char)))
          (when (or (aref (char-category-set next) ?|)
                    (aref (char-category-set prev) ?|))
            (delete-char -1)))))

(snip) (snip) (snip)
;; Is comment appropriate?

If no objection, I'll commit this tonight.
> 
> What I don't like is the name `LaTeX-word-across-newline'.  What about
> something matching better its value/purpose, like
> `LaTeX-nospace-between-words-char-regexp'.  Argh, I created a
> monster.  A little bit shorter: `LaTeX-nospace-between-char-regexp'.
> Any better suggestions?

I like it.

---
email: [email protected]
Name:: Masayuki Ataka // (Japan)