multibyte issues in overwrite-mode

[jay]

Hello,

When inserting multi-byte characters in overwrite-mode, emacs deletes just
one character following the cursor, meaning that emacs treats characters
uniform ways. I think there should be some options for this behaviour, since
the user don't want to adjust the template text after inserting multi-byte
characters sometimes. Options like 'overwrite-preserve-text-width' or
something.

Here's each of the possible scenarios. For convenience, lower cases denote
unibyte-character and upper-case characters denote multi-byte characters.

  - characters following current cursor position: ab, aA, Aa, AB
  - inserting character : A, a

     |  ab   |  aA   |  Aa   |  AB   |
  ---+-------+-------+-------+-------+
   c |  cb   |  cA   |  (1)  |  (1)  |
  ---+-------+-------+-------+-------+
   C |  (3)  |  (4)  |  Ca   |  CB   |

With the option turned on, emacs's behaviour is like this:

  for case 3, the result should be C - not Cb.

  for other cases, emacs inserts C and delete aA altogether, and then
  insert some designated character meaning that the character is
  half-broken. of course the designated character is unibyte-character, say
  '?'.

what do you, guys think about it?

-- 
Jaeyoun Chung                       mailto:address@hidden
[see http://emacs.kldp.org for emacs-KR homepage.]