Shawn Steele
2011-09-22 15:27:26 UTC
That's why a definition would've been good :)
I'm not sure there's much point to add the information "now". Either your app's stuck with some legacy restriction requiring code page support or you should be using Unicode. So either some code page(s) you already know about on this list are important to you, or they aren't. Whether we call them "common, limited, or obsolete" doesn't change that.
It might be good if http://www.iana.org/assignments/character-sets and http://www.iana.org/assignments/charset-reg/index.html were updated to include a note to the effect that UTF-8 or UTF-16 may be preferred in many cases, something like:
"Many character sets are limited in their scope and many others have inconsistent implementations between vendors. To enable the broadest set of characters in a manner that is most consistent between vendors, implementers should consider using UTF-8 or UTF-16."
-Shawn
http://blogs.msdn.com/shawnste
________________________________________
From: "Martin J. Dürst" [***@it.aoyama.ac.jp]
Sent: Wednesday, September 21, 2011 9:09 PM
To: Shawn Steele
Cc: Ira McDonald; ietf-***@mail.apps.ietf.org; Makoto Murata (eb2m-***@asahi-net.or.jp)
Subject: Re: Big5 / CP950
For some more comments, please see below.
charset registry was created, but with a later update.
I assume the distinction between COMMON and LIMITED USE was originally
intended as some kind of advice to implementers: If it's COMMON, then
make sure it's supported, if it's LIMITED USE, you may not need it. But
I don't think that has ever really worked.
idea. Assuming that everybody's time is rather limited, it may have to
wait. There are quite a few other things in the registry that might
benefit from clearing up, but the critical mass may not be reached yet.
some other places). There's no need to keep that kind of information in
separate templates.
Regards, Martin.
I'm not sure there's much point to add the information "now". Either your app's stuck with some legacy restriction requiring code page support or you should be using Unicode. So either some code page(s) you already know about on this list are important to you, or they aren't. Whether we call them "common, limited, or obsolete" doesn't change that.
It might be good if http://www.iana.org/assignments/character-sets and http://www.iana.org/assignments/charset-reg/index.html were updated to include a note to the effect that UTF-8 or UTF-16 may be preferred in many cases, something like:
"Many character sets are limited in their scope and many others have inconsistent implementations between vendors. To enable the broadest set of characters in a manner that is most consistent between vendors, implementers should consider using UTF-8 or UTF-16."
-Shawn
http://blogs.msdn.com/shawnste
________________________________________
From: "Martin J. Dürst" [***@it.aoyama.ac.jp]
Sent: Wednesday, September 21, 2011 9:09 PM
To: Shawn Steele
Cc: Ira McDonald; ietf-***@mail.apps.ietf.org; Makoto Murata (eb2m-***@asahi-net.or.jp)
Subject: Re: Big5 / CP950
I saw the “one of…”, but they aren’t defined in the RFC? Your spirit of Limited Use sounds about right for big5 though.
I agree.For some more comments, please see below.
Thanks,
Shawn
Sent: Wednesday, September 21, 2011 9:41 AM
To: Shawn Steele; Ira McDonald
Subject: Re: Big5 / CP950
Hi Shawn,
RFC 2978 section 5 'Charset Registration Template'
(One of COMMON, LIMITED USE or OBSOLETE)"
The spirit of LIMITED USE has been to discourage the use
of legacy charsets that are particularly problematic - Big5.
Not sure if OBSOLETE has ever been used.
I haven't checked, but I guess these were not introduced when theShawn
Sent: Wednesday, September 21, 2011 9:41 AM
To: Shawn Steele; Ira McDonald
Subject: Re: Big5 / CP950
Hi Shawn,
RFC 2978 section 5 'Charset Registration Template'
(One of COMMON, LIMITED USE or OBSOLETE)"
The spirit of LIMITED USE has been to discourage the use
of legacy charsets that are particularly problematic - Big5.
Not sure if OBSOLETE has ever been used.
charset registry was created, but with a later update.
I assume the distinction between COMMON and LIMITED USE was originally
intended as some kind of advice to implementers: If it's COMMON, then
make sure it's supported, if it's LIMITED USE, you may not need it. But
I don't think that has ever really worked.
Martin - searching for this made me realize that the
plaintext IANA Charset Registry at
ftp://ftp.iana.org/assignments/character-sets
contains 257 entries - they don't include the Intended
Usage field.
I suggest we work w/ IANA to change the plaintext
registry.
Assuming somebody has lots of spare time, that would indeed be a goodplaintext IANA Charset Registry at
ftp://ftp.iana.org/assignments/character-sets
contains 257 entries - they don't include the Intended
Usage field.
I suggest we work w/ IANA to change the plaintext
registry.
idea. Assuming that everybody's time is rather limited, it may have to
wait. There are quite a few other things in the registry that might
benefit from clearing up, but the critical mass may not be reached yet.
In most cases this data is long lost (if ever submitted)
because the directory
ftp://ftp.iana.org/assignments/charset-reg
contains only 55 entries.
Lots of stuff was taken from http://tools.ietf.org/html/rfc1345 (andbecause the directory
ftp://ftp.iana.org/assignments/charset-reg
contains only 55 entries.
some other places). There's no need to keep that kind of information in
separate templates.
Regards, Martin.
Cheers,
- Ira
Ira McDonald (Musician / Software Architect)
Chair - Linux Foundation Open Printing WG
Co-Chair - IEEE-ISTO PWG IPP WG
Chair - TCG Embedded Systems Hardcopy SWG
IETF Designated Expert - IPP& Printer MIB
Blue Roof Music/High North Inc
http://sites.google.com/site/blueroofmusic
http://sites.google.com/site/highnorthinc
579 Park Place Saline, MI 48176
734-944-0094
PO Box 221 Grand Marais, MI 49839
90
- Ira
Ira McDonald (Musician / Software Architect)
Chair - Linux Foundation Open Printing WG
Co-Chair - IEEE-ISTO PWG IPP WG
Chair - TCG Embedded Systems Hardcopy SWG
IETF Designated Expert - IPP& Printer MIB
Blue Roof Music/High North Inc
http://sites.google.com/site/blueroofmusic
http://sites.google.com/site/highnorthinc
579 Park Place Saline, MI 48176
734-944-0094
PO Box 221 Grand Marais, MI 49839
90