Re: Use of LWSP in ABNF -- consensus call

Tony Finch <dot@dotat.at> Tue, 15 May 2007 08:10 UTC

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Date: Tue, 15 May 2007 09:10:41 +0100
From: Tony Finch <dot@dotat.at>
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To: dcrocker@bbiw.net
Subject: Re: Use of LWSP in ABNF -- consensus call
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On Mon, 14 May 2007, Dave Crocker wrote:
>
>      "Could cause problems in other places"...  The DKIM hiccup was the first
> one I'd heard about.
>
>      By contrast, "linear-white-space" was defined in RFC733, in 1977, with
> RFC822 retaining that definition.  It is defined in those places as
> essentially the same as LWSP in the current ABNF Draft Standard specification.

The LWSP defined in ABNF is more like the one in HTTP than the message
format one, in that 4234 allows space-only lines (it allows multiple CRLFs
in LWSP) whereas 2822 does not (at most one CRLF in FWS).

There is some documentation of the interoperability problems arising from
the implied-LWS rule in HTTP here:
http://www.and.org/texts/server-http#implicit-lws

Tony.
-- 
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