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Re: raw-byte and char-table
From: |
Kenichi Handa |
Subject: |
Re: raw-byte and char-table |
Date: |
Wed, 25 Aug 2010 13:05:43 +0900 |
In article <address@hidden>, Eli Zaretskii <address@hidden> writes:
> > > > (aref CHAR-TABLE (unibyte-char-to-multibyte #xA0))
> > > > (aset CHAR-TABLE (unibyte-char-to-multibyte #xA0) VALUE)
> >
> > > One could also use the codepoint of the corresponding eight-bit
> > > character directly, no?
> >
> > Like #x3FFFA0? It's possible but should not be recommended.
> Why not recommended? We already document in the ELisp manual the
> codepoints to which we map eight-bit bytes. It's not a secret, it's
> in the open.
Number like #x3FFFA0 is so criptic. The function name
unibyte-char-to-multibyte is also not ideal, but I think
it's better than #x3FFFA0.
> > As for a display table, we have one more problem. Currently
> > an element of a display table is nil or a vector of
> > characters. To directly output the byte #xA0 to a terminal,
> > perhaps the correct way is to set (unibyte-char-to-multibyte
> > #xA0) in a vector. That way, we can specify any byte(s) to
> > send to a terminal.
> >
> > But, then, what is the semantics of the vector element
> > (unibyte-char-to-multibyte #xA0) for a graphic device? What
> > should we display for CHAR if we setup
> > standard-display-table as this?
> >
> > (aset standard-display-table
> > CHAR (vector (unibyte-char-to-multibyte #xA0)))
> There's something I'm missing here: why text terminals and graphics
> terminals are different in this context? It seems that you are saying
> that was is correct for a text terminal does not have a clear
> semantics for a GUI terminal,
Yes.
> but why?
What we can send to a terminal is a byte. So, by having a
method of specifying any raw byte directly, we can send all
possible bytes to a terminal. For a graphic device, the
natural interpretation corresponding to "directly sending a
raw byte" is, I think, "directly specifying a glyph code".
But, to specify all possible glyph codes, 0x80..0xFF is not
enough.
---
Kenichi Handa
address@hidden
- Re: raw-byte and char-table, MON KEY, 2010/08/25
- Re: raw-byte and char-table, Kenichi Handa, 2010/08/25
- Re: raw-byte and char-table, MON KEY, 2010/08/26
- Re: raw-byte and char-table, Kenichi Handa, 2010/08/26
- Re: raw-byte and char-table, Miles Bader, 2010/08/26
- Re: raw-byte and char-table, MON KEY, 2010/08/26
- Re: raw-byte and char-table, Kenichi Handa, 2010/08/26