raw-byte and char-table

[Kenichi Handa]

A char-table is a table indexed by a character code.  So,
it's 0xA0th element is a value for a character U+00A0.
Then, how to set/get a value for raw-byte 0xA0?  Currently,
this is the way to do that:

  (aref CHAR-TABLE (unibyte-char-to-multibyte #xA0))
  (aset CHAR-TABLE (unibyte-char-to-multibyte #xA0) VALUE)

But, this is not documented.  Should we document it?

A display-table is a char-table.  But, the current code uses
0xA0th element of a display-table for both U+00A0 and
raw-byte 0xA0.  For instance, in get_next_display_element of
xdisp.c:

5744      if (it->dp
5745          && (dv = DISP_CHAR_VECTOR (it->dp, it->c),
5746              VECTORP (dv)))

Here, it->c may be 0xA0 comming from a unibyte buffer/string.

Should we change the above code and all other codes setting
0x80th..0xA0th elements of a display table?

---
Kenichi Handa
address@hidden