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RE: ambiguity in BNF: no non-numeric TLDs?

From: Michel Suignard <michelsu@windows.microsoft.com>
Date: Thu, 13 Nov 2003 18:29:50 -0800
Message-ID: <84DD35E3DD87D5489AC42A59926DABE904A854AB@WIN-MSG-10.wingroup.windeploy.ntdev.microsoft.com>
To: "Roy T. Fielding" <fielding@apache.org>
Cc: <uri@w3.org>, "Larry Masinter" <LMM@acm.org>

I guess we need to make sure we have similar text in IRI.
BTW Roy, when can we expect your revised RFC2396 text to move ahead? IRI
has a dependency on it.

Michel

-----Original Message-----
From: Roy T. Fielding [mailto:fielding@apache.org] 

> Can we assume that TLDs will be non-numeric?

Yes, but we can't assume that the last domain is a TLD.

> It looks to me that the BNF is ambiguous between hostname and IPv4 
> addresses because the BNF for hostname doesn't rule out
>   nnn.nnn.nnn.nnn

Yes, it says that in the text describing the rule:

    The production for host is ambiguous because it does not completely
    distinguish between an IPv4address and a hostname.  Again, the
    "first-match-wins" algorithm applies: If host matches the production
    for IPv4address, then it should be considered an IPv4 address
literal
    and not a hostname.

All of our attempts to disambiguate within the grammar itself did not
work because, without a trailing ".", there is no way to know which is
the TLD.

....Roy
Received on Thursday, 13 November 2003 21:29:55 GMT

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