Subject: [Ltru] Re: [psg.com #1011] add suppress-region

From: "Doug Ewell" <[email-masked]>
Date: Sun, 29 May 2005 18:25:49 -0700

Frank Ellermann <nobody at xyzzy dot claranet dot de> wrote:

> I'm still lost with multiple extlang-s in a tag, how many in
> which order ?  Draft -03pre still says *( "-" extlang ).  The
> maximum Recommended-Prefix allows 17 extlang-s.

Extended-language subtags really have nothing to do with
Recommended-Prefix fields.  That is, I suppose an RP field might have as
its value a prefix that included an extlang subtag, but I still don't
see the connection.  (I also don't see where this 17 limit came from.)

> We are sure that this will never happen, and it wouldn't work
> in encoded word (RfC 2047).  But the draft -03pre doesn't say
> so, it also does not yet mention RfC 2047 together with 2231.

The draft says very little about extlangs in general, except that they
are reserved for the future.  I really don't see what the fuss is *right
now*.

> This one * before extlang in the ABNF will fascinate developers
> in the "last call", it triggers nightmares of buffer overflows
> and memory leaks.

As a C and C++ developer -- languages infamous for their vulnerability
to buffer overflows -- I responded to the star with caution, but no
nightmares.  My validator has a fixed internal upper limit of 1,024
characters per tag, which is the sort of limit that should be documented
in accordance with Section 2.1.1.  A tag with 17 (or 256)
extended-language subtags would be syntactically legal ("well-formed")
but not semantically legal ("valid") as long as there are no extlang
subtags in the registry.  My validator doesn't care how many extlang
subtags it finds, but if the total tag length is over 1,024 it will
silently truncate the tag.  (A message might be better.)

Memory leaks are always the fault of the developer (or rarely, a buggy
development environment) -- never the spec.

Since this is all moot, and the mechanism really nothing more than a
placeholder, until RFC 3066ter is ready to be discussed, I suggest we
not worry about it right now.

--
Doug Ewell
Fullerton, California
http://users.adelphia.net/~dewell/

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---

From: Frank Ellermann <[email-masked]>
Date: Mon, 30 May 2005 04:50:05 +0200

Doug Ewell wrote:
 
> Recommended-Prefix fields.

Okay, then let's add Macro-Language to our field name zoo.
Assuming that a redundant extlang makes technically sense.

> (I also don't see where this 17 limit came from.)

72 is the line length in the registry.  LWSP allows to fold
behind the colon, Macro-Language:<CRLF><SP>lng-ex1-etc<CRLF>

72 minus one SP minus three "lng" is 68, and 68 / (1+3) = 17.

> I really don't see what the fuss is *right now*.

The fuss is that *("-" extlang) was discussed quite often,
but I never got the idea that it's _redundant_ info.  

And we're supposed to prepare anything as far as possible
for the extlang-s, and that would require a field name
"Macro-Language:" (or similar), because adding new field
names later could break some new 3066bis registry readers.

> I responded to the star with caution, but no nightmares.

These tags might be used in any piece of MIME compatible
software in some way, in any browser, in any Web server,
in any XML lib, Ned mentioned IMAP, we talked about JAVA.

> Memory leaks are always the fault of the developer (or
> rarely, a buggy development environment) -- never the spec.

The spec. should be KISS where possible.  Reserving 1 KB
per tag is fine when you have it, but some devices might
be forced to find a smaller buffer size still trying to 
support all "important" subtags (up to and including the
"script").  And *("-" extlang) comes before the "script".

                      Bye, Frank

---

From: "Randy Presuhn" <[email-masked]>
Date: Tue, 31 May 2005 12:57:56 -0700

Hi -

It looks like there is no consensus to add "suppress-region",
so I'll mark this issue "rejected".  If further discussion
is necessary, please use an appropriate subject line.

Randy, ltru co-chair