>>>>> "Eli" == Eli Zaretskii <eliz@gnu.org> writes:

    >> From: Chen Bin <chenbin.sh@gmail.com> Cc: emacs-devel@gnu.org
    >> Date: Sun, 15 Apr 2018 02:40:18 +1000
    >> 
    >> Correct me if I'm wrong.
    >> 
    >> I read cod eand found definion of Lisp_String: struct GCALIGNED
    >> Lisp_String { ptrdiff_t size; ptrdiff_t size_byte; INTERVAL
    >> intervals; /* Text properties in this string.  */ unsigned char
    >> *data; };
    >> 
    >> I understand string text is encoded in UTF8 format and is stored
    >> in 'Lisp_String::data'. There is actually no difference between
    >> unibyte and multibyte text since UTF8 is compatible with ASCII
    >> and we only deal with 'data' field.

    Eli> No, that's incorrect.  The difference does exist, it just all
    Eli> but disappear for unibyte strings encoded in UTF-8.  But if you
    Eli> encode a string in some other encoding, like Latin-1, you will
    Eli> see a very different stream of bytes.

    >> I attached the latest patch.

    Eli> Thanks.

    >> + ;; string containing unicode character (Hanzi) + (should (equal
    >> 6 (string-distance "ab" "ab我她"))) + (should (equal 3
    >> (string-distance "我" "她"))))

    Eli> Should the distance be measured in bytes or in characters?  I
    Eli> think it's the latter, in which case the implementation should
    Eli> work in characters, not bytes.

-- 
Best Regards,
Chen Bin

--
Help me, help you