Re: File name completion on Mac OS X with German umlauts

[Nikolaj Schumacher]

Eli Zaretskii <eliz@gnu.org> wrote:

>> From: Nikolaj Schumacher <n_schumacher@web.de>
>>
>> This is very interesting.  Apparently `read-file-name' doesn't use
>> `file-name-coding-system' when completing.
>
> How do you see that?  Just looking at the sources, I see it does.

Sorry, I phrased that poorly.  I only intended to express a suspicion...

After some actual research, I the real reason appears to be that
utf-8m.el only offers one-way transformation and `read-file-name' needs
the other direction.

A naive attempt of adding that worked surprisingly well.  The only issue
I have is that Emacs always says "Complete, but not unique".  Don't know
why, yet.



(require 'utf-8m)

(defun utf-8m-pre-write-conversion (beg end)
  (save-excursion ;; conversion (NFC -> NFD)
    (save-restriction
      (narrow-to-region beg end)
      (let ((str (buffer-string)))
        (delete-region (point-min) (point-max))
        (insert
         (decode-coding-string
          (or (mac-code-convert-string
               (encode-coding-string str 'utf-8) 'utf-8 'utf-8 'NFD) "")
          'utf-8)
          ))
      )))

(make-coding-system
 'utf-8m-alt 4 ?U
 "modified UTF-8 encoding for Mac OS X hfs plus volume format."
 '(ccl-decode-mule-utf-8 . ccl-encode-mule-utf-8)
 `((safe-charsets
    ascii
    eight-bit-control
    eight-bit-graphic
    latin-iso8859-1
    mule-unicode-0100-24ff
    mule-unicode-2500-33ff
    mule-unicode-e000-ffff
    ,@(if utf-translate-cjk-mode
          utf-translate-cjk-charsets))
   (mime-charset . nil)
   (coding-category . coding-category-utf-8)
   (valid-codes (0 . 255))
   (pre-write-conversion . ,(if (fboundp 'mac-code-convert-string)
                                'utf-8m-pre-write-conversion
                              'utf-8-pre-write-conversion))
   ,(if (functionp 'mac-code-convert-string)
        '(post-read-conversion . utf-8m-e22-mac-post-read-conversion)
      '(post-read-conversion . utf-8m-e22-post-read-conversion))
   (translation-table-for-encode . utf-translation-table-for-encode)
   (dependency unify-8859-on-encoding-mode
               unify-8859-on-decoding-mode
               utf-fragment-on-decoding
               utf-translate-cjk-mode)))


(require 'utf-8m-alt)
(setq file-name-coding-system 'utf-8m-alt)


regards,
Nikolaj Schumacher