In article <[EMAIL PROTECTED]>, David Kastrup <[EMAIL PROTECTED]> writes:
> I have the problem that within preview-latex there is a function that
> assembles UTF-8 strings from single characters. This function, when
> used manually, mostly works. It is called within a process sentinel
> and fails rather consistently there with a current CVS Emacs. I
> include the code here since I don't know what might be involved here:
> regexp-quote, substring, char-to-string etc. The starting string is
> taken from a buffer containing only ASCII (inserted by a process with
> coding-system 'raw-text).
It seems that you are caught in a trap of automatic
unibyte->multibyte conversion.
> (defun preview-error-quote (string)
> "Turn STRING with potential ^^ sequences into a regexp.
> To preserve sanity, additional ^ prefixes are matched literally,
> so the character represented by ^^^ preceding extended characters
> will not get matched, usually."
> (let (output case-fold-search)
> (while (string-match "\\^\\{2,\\}\\(\\([EMAIL
> PROTECTED])\\|[8-9a-f][0-9a-f]\\)"
> string)
> (setq output
> (concat output
> (regexp-quote (substring string
> 0
> (- (match-beginning 1) 2)))
If STRING is taken from a multibyte buffer, it is a
multibyte string. Thus, the above substring also returns a
multibyte string.
> (if (match-beginning 2)
> (concat
> "\\(?:" (regexp-quote
> (substring string
> (- (match-beginning 1) 2)
> (match-end 0)))
> "\\|"
> (char-to-string
> (logxor (aref string (match-beginning 2)) 64))
> "\\)")
> (char-to-string
> (string-to-number (match-string 1 string) 16))))
But, this char-to-string produces a unibyte string. So, on
concatinating them, this unibyte string is automatically
converted to multibyte by string-make-multibyte function
which usually produces a multibyte string containing latin-1
chars.
> string (substring string (match-end 0))))
> (setq output (concat output (regexp-quote string)))
> (if (featurep 'mule)
> (prog2
> (message "%S %S " output buffer-file-coding-system)
> (setq output (decode-coding-string output
> buffer-file-coding-system))
And this decode-coding-string treats the internal byte
sequence of a multibyte string OUTPUT as utf-8, thus you get
some garbage.
> Unfortunately, when I call this stuff by hand instead from the
> process-sentinel, it mostly works
That is because the string you give to preview-error-quote
is a unibyte string in that case. The Lisp reader generates
a unibyte string when it sees ASCII-only string.
Ex: (multibyte-string-p "abc") => nil
This will also return incorrect string.
(preview-error-quote
(string-to-multibyte "r Weise $f$ um~$1$ erh^^c3^^b6ht und $e$"))
So, the easiest fix will be to do:
(setq string (string-as-unibyte string))
in the head of preview-error-quote.
---
Ken'ichi HANDA
[EMAIL PROTECTED]
_______________________________________________
Emacs-devel mailing list
Emacs-devel@gnu.org
http://lists.gnu.org/mailman/listinfo/emacs-devel
