Re: Bug 130397

[Kenichi Handa]

In article <address@hidden>, Stefan <address@hidden> writes:

>>  Hmmm, then how about the attached patch to the latest CVS
>>  emacs?  With that, all equivalent charaters (e.g a-grave in
>>  all laitn-X) should be handled well.  This patch will be
>>  applicable also to Emacs 21.3 but not yet tested in that
>>  version.

> Can someone explain to me why ispell.el needs those kinds of things?

> My vague understanding is that ispell.el needs to know which chars are part
> of a word and that in the past (pre-MULE), this had to be redefined for each
> and every language since the codes 128-255 could mean completely
> different things.

> Why can't ispell.el just use the `w' syntax to decide what is a word and
> then rely on the decoding/encoding to do the rest of the work?

> That would fix the problem where a word like "expérience" is checked as two
> words if the dictionary is "american".

That will cause another problem.  For instance, when we have
"español" in a buffer and the ispell dictionary is czech
(latin-2), as "español" is encoded into "espa?ol" by
latin-2, it causes the error "Ispell and its process have
different character maps" because ispell returns the result
of two words "eapa" and "ol".

>>  + ;; Char-table that maps an Unicode character (charset:
>>  + ;; latin-iso8859-1, mule-unicode-0100-24ff) to
>>  + ;; a string in which all equivalent characters are listed.
>>  + 
>>  + (defconst ispell-unified-chars-table
>>  +   (let ((table (make-char-table 'ispell-unified-chars-table)))
>>  +     (map-char-table
>>  +      #'(lambda (c v)
>>  +    (if (and v (/= c v))
>>  +        (let ((unified (or (aref table v) (string v))))
>>  +          (aset table v (concat unified (string c))))))
>>  +      ucs-mule-8859-to-mule-unicode)
>>  +     table))

> All the elements of this table should be multibyte strings.
> For this, we may need to wrap the (string X) into
> (string-to-multibyte (string X))

As `c' and `v' are always multibyte characters, (string X)
always return a multibyte string.

>>  +           (string-as-multibyte
>>  +            (mapconcat
>>  +             #'(lambda (c)
>>  +                 (let ((unichar (aref ucs-mule-8859-to-mule-unicode c)))
>>  +                   (if unichar
>>  +                       (aref ispell-unified-chars-table unichar)
>>  +                     (string c))))
>>  +             str ""))))

> Do you expect the output of mapconcat to be unibyte and to contain
> emacs-mule encoding of multibyte chars?

No.  STR may be an ASCII-only string, in which case, the
result of mapconcat is a unibyte ASCII-only string.  I'd
like to change it to a multibyte ASCII-only stirng to avoid
converting STR again and again in such a case.

---
Ken'ichi HANDA
address@hidden