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Re: RFC 2231 and CFWS

2003-01-24 10:16:00

In <200301231352(_dot_)55817(_at_)sendmail(_dot_)mutz(_dot_)com> Marc Mutz 
<mutz(_at_)kde(_dot_)org> writes:

On Thursday 23 January 2003 11:58, Charles Lindsey wrote:

    ()token*0()=3D()token()
       ditto   =3D()"quoted-string"()
       ditto   =3D()ascii'en_US'foo%20bar()


All extended-*-{name,value}s? productions are designed to be recognized
as "token" by pre-2231 parsers. Following that thought through will
give you quite naturally the idea of where CFWS can occur.

OK, thanks to all concerned. I can now see how to write a syntax with CFWS
in the right places.

However, on reading the syntax in RFC 2231, I now find a few further
oddities.

1. Broken backwards compatibility

Under RFC 2046, I could write

        x-foo'bar = baz

But that is not allowed now.

OTOH, I can still write

        charset = x-foo'bar

but not

        charset* = ''x-foo'bar

But I thought the IETF "didn't do" backwards incompatibility (Cue howls of
protest from Bruce Lilley) :-( .

And it might have been simpler just to add "'", "*" and "%" to tspecials,
for the removal of all confusion.

2. IANA registered charsets

Under RFC 2046, it was allowed to register "foo'bar" as a charset (it was
just required to be a token). Presumably, this is not allowed now, but
where is it actually written down what may be registered as a charset?
AFAICS, that IANA registry was created by RFC 2046.

3. IMAP

I see that RFC 2231 makes a minor change to IMAP ("SHOULD decode parameter
value continuations"). To be very pedantic, shouldn't RFC 2231 have been
described as "Updates RFC 2060"?

-- 
Charles H. Lindsey ---------At Home, doing my own thing------------------------
Tel: +44 161 436 6131 Fax: +44 161 436 6133   Web: http://www.cs.man.ac.uk/~chl
Email: chl(_at_)clw(_dot_)cs(_dot_)man(_dot_)ac(_dot_)uk      Snail: 5 
Clerewood Ave, CHEADLE, SK8 3JU, U.K.
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