Subject: Re: [EAI] Consensus Issue #1: parameter on MAIL FROM?

From: Shawn Steele <[email-masked]>
Date: Thu, 20 Jan 2011 20:11:27 +0000

We're digressing, but it depends on whether or not you want the recipient to be able to be guaranteed to correctly decode the message.  All of the CJK encodings have encoding variations between platforms, vendors and systems.  Wikipedia lists some of them.  Most of the problems around encodings have to do with those types of inconsistencies.  A few extra bytes is worth the guarantee.  (And if you attach a picture, then the size difference becomes meaningless).  In practice the size difference is probably only interesting for a text message on a satellite phone.

-Shawn

------------------------------

Message: 2
Date: Thu, 20 Jan 2011 13:44:55 -0000
From: "Charles Lindsey" <[email-masked]>
Subject: Re: [EAI] Consensus Issue #1:  parameter on MAIL FROM?
To: IMA <[email-masked]>
Message-ID: <[email-masked]>
Content-Type: text/plain; format=flowed; delsp=yes; charset=iso-8859-1

On Wed, 19 Jan 2011 19:01:48 -0000, <[email-masked]> wrote:

>> Nothing requires UTF-8, but we certainly strongly suggest that EAI  
>> messages
>> are entirely UTF-8.  IMO you'd be a pretty ugly EAI implementation if  
>> that
>> wasn't your default.
>
> I think this is a very good point worthy of a separate consensus call -  
> the
> format document needs to say something like:
>
>     Media types that support multiple charsets SHOULD employ either
>     utf-8 or us-ascii.

Not necessarily. If the body of the message cotains some long text in
Chinese, then using some charset encoding other than UTF-8 might make good  
sense because than encoding may be more compact. UTF-8 can often use 3  
(even 4) bytes to encode a character that other charsets can encode in 2  
bytes. In headers, one can tolerate those extra bytes, but not so in long  
bodies.

-- 
Charles?H.?Lindsey?---------At?Home,?doing?my?own?thing------------------------
Tel:?+44?161?436?6131?                      
???Web:?http://www.cs.man.ac.uk/~chl
Email:?[email-masked]??????Snail:?5?Clerewood?Ave,?CHEADLE,?SK8?3JU,?U.K.
PGP:?2C15F1A9??????Fingerprint:?73?6D?C2?51?93?A0?01?E7?65?E8?64?7E?14?A4?AB?A5

---

From: [email-masked]
Date: Thu, 20 Jan 2011 15:03:59 -0800 (PST)

> We're digressing,

Again, I think this is sufficiently important it deserves to be called out
as s separate issue to address.

> but it depends on whether or not you want the recipient to
> be able to be guaranteed to correctly decode the message.  All of the CJK
> encodings have encoding variations between platforms, vendors and systems. 
> Wikipedia lists some of them.

UTF-8 is the exception here, which is why we need to encourage it's use. (OK,
so is UTF-16, but it has other issues.)

> Most of the problems around encodings have to do with those types of
> inconsistencies.  A few extra bytes is worth the guarantee.

Almost always. But this is why I recommended a SHOULD, not a MUST. If a case
arises where the increased size is really more of an issue than the myriad
problems that arise from the generally crappy state of CJK encodings, then
there's sufficient justification to be able to violate the SHOULD and still be
able to claim compliance.

> (And if you attach a picture, then the size difference becomes meaningless). 
> In practice the size difference is probably only interesting for a text message
> on a satellite phone.

Indeed. We spend WAY too much time overoptimizing this sort of thing.

				Ned

---

From: Shawn Steele <[email-masked]>
Date: Thu, 20 Jan 2011 23:13:38 +0000

I think I said SHOULD?

-----Original Message-----
From: Ned Freed [mailto:[email-masked]] 
Sent: Poʻahā, Ianuali 20, 2011 3:04 hours
To: Shawn Steele
Cc: [email-masked]
Subject: Re: [EAI] Consensus Issue #1: parameter on MAIL FROM?

> We're digressing,

Again, I think this is sufficiently important it deserves to be called out as s separate issue to address.

> but it depends on whether or not you want the recipient to be able to 
> be guaranteed to correctly decode the message.  All of the CJK 

UTF-8 is the exception here, which is why we need to encourage it's use. (OK, so is UTF-16, but it has other issues.)

> inconsistencies.  A few extra bytes is worth the guarantee.

Almost always. But this is why I recommended a SHOULD, not a MUST. If a case arises where the increased size is really more of an issue than the myriad problems that arise from the generally crappy state of CJK encodings, then there's sufficient justification to be able to violate the SHOULD and still be able to claim compliance.

> In practice the size difference is probably only interesting for a 
> text message on a satellite phone.

				Ned

---

From: [email-masked]
Date: Thu, 20 Jan 2011 15:25:20 -0800 (PST)

> I think I said SHOULD?

Yes; my point was that even if Charles' objection is legitimte, the necessary
freedom to use other CJK encodings isn't being eliminated by what we're
proposing.

				Ned

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