multiple destinations in charset mapping files

multiple destinations in charset mapping files

[YAMAMOTO Mitsuharu]

I noticed that some charset mapping files such as
etc/charsets/symbol.map contain entries where the same source is
mapped to multiple destinations, and the latter one is preferred in
decoding in such cases.

  0x20 0x0020
  0x20 0x00A0

  (decode-char 'symbol #x20) -> 160

But at least for symbol.map, it seems to be more natural to prefer the
former entry (e.g., SPACE vs. NO-BRAKE SPACE, GREEK CAPITAL LETTER
DELTA vs. INCREMENT).  WDYT?

				     YAMAMOTO Mitsuharu
				mituharu@math.s.chiba-u.ac.jp

Re: multiple destinations in charset mapping files

[Kenichi Handa]

In article <wlab3y9hkj.wl%mituharu@math.s.chiba-u.ac.jp>, YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp> writes:

> I noticed that some charset mapping files such as
> etc/charsets/symbol.map contain entries where the same source is
> mapped to multiple destinations, and the latter one is preferred in
> decoding in such cases.

>   0x20 0x0020
>   0x20 0x00A0

>   (decode-char 'symbol #x20) -> 160

> But at least for symbol.map, it seems to be more natural to prefer the
> former entry (e.g., SPACE vs. NO-BRAKE SPACE, GREEK CAPITAL LETTER
> DELTA vs. INCREMENT).  WDYT?

I agree.  By this script in etc/charsets:

% for f in *.map; do awk '{print $1}' < $f | sort | uniq -c | grep '^ *[2-9] 0' && echo $f; done

I confirmed only symbol.map and stdenc.map contain such
duplications, so I regenrated those maps (simply by doing
sort -r) and committed to EMACS_23_1_RC and trunk.

Do you find any other maps that have duplications?

---
Kenichi Handa
handa@m17n.org

Re: multiple destinations in charset mapping files

[YAMAMOTO Mitsuharu]

>>>>> On Thu, 25 Jun 2009 09:36:36 +0900, Kenichi Handa <handa@m17n.org> said:

> I confirmed only symbol.map and stdenc.map contain such
> duplications, so I regenrated those maps (simply by doing sort -r)
> and committed to EMACS_23_1_RC and trunk.

Thanks.  It becomes more consistent than before.

But maybe I should have checked the mapping more in detail.  It seems
that the preference of the preceding entry does not always give a
consistent result:

03BB	6C	# GREEK SMALL LETTER LAMDA	# lambda
00B5	6D	# MICRO SIGN	# mu
03BC	6D	# GREEK SMALL LETTER MU	# mu
03BD	6E	# GREEK SMALL LETTER NU	# nu

I don't have a good (non ad-hoc) idea to prefer GREEK SMALL LETTER MU
to MICRO SIGN for this case.

> Do you find any other maps that have duplications?

Though I didn't mechanically checked, there's nothing else I found so
far.

				     YAMAMOTO Mitsuharu
				mituharu@math.s.chiba-u.ac.jp

Re: multiple destinations in charset mapping files

[Kenichi Handa]

In article <wlbpodniwu.wl%mituharu@math.s.chiba-u.ac.jp>, YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp> writes:

> But maybe I should have checked the mapping more in detail.  It seems
> that the preference of the preceding entry does not always give a
> consistent result:

> 03BB	6C	# GREEK SMALL LETTER LAMDA	# lambda
> 00B5	6D	# MICRO SIGN	# mu
> 03BC	6D	# GREEK SMALL LETTER MU	# mu
> 03BD	6E	# GREEK SMALL LETTER NU	# nu

> I don't have a good (non ad-hoc) idea to prefer GREEK SMALL LETTER MU
> to MICRO SIGN for this case.

Me neither.  :-(

---
Kenichi Handa
handa@m17n.org