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Re: identifier in draft-ietf-httpbis-header-structure-01.txt

From: Poul-Henning Kamp <phk@phk.freebsd.dk>
Date: Sun, 30 Apr 2017 07:48:19 +0000
To: Alex Rousskov <rousskov@measurement-factory.com>
cc: HTTP working group mailing list <ietf-http-wg@w3.org>
Message-ID: <6849.1493538499@critter.freebsd.dk>
--------
In message <22726a23-fa30-8c36-833e-8c75a474a18f@measurement-factory.com>, Alex
 Rousskov writes:
>On 04/29/2017 11:45 AM, Poul-Henning Kamp wrote:

>> And yes, in HTTP/1.1 serialization you cannot tell if a particular
>> identifier is a word or a number, you need to definition of the
>> header in question to tell you that, that's the cost of a very
>> concise definition and backwards compatibility with standardized
>> headers.
>
>The "cost" part does not compute: A grammar without any "integer"
>element would be even more "concise" and still backwards compatible.

The serialization in HTTP/2/HPACK+ or QUIC might distinguish between
identifiers and numbers for efficiency reasons.

>IMHO, if the grammar remains ambiguous, then we should explicitly state
>that because that property may seriously affect parser implementations.

Header Structure is not a syntactical specification, so the ambiguity
is not a problem.  HS is more like a vocabulary trying to prevent
future headers from being needlessly inventive.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.
Received on Sunday, 30 April 2017 07:48:51 UTC

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