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Re: [ietf-dkim] Re: Use of LWSP in ABNF -- consensus call

2007-05-17 18:15:19


--On Thursday, 17 May, 2007 21:52 +0200 Harald Tveit Alvestrand
<harald(_at_)alvestrand(_dot_)no> wrote:

I don't agree with the meaning I get from this statement. The
problem is that the construct that ABNF calls "LWSP" causes
problems in protocols that use it.
This problem is independent of the name of the construct; the
problem is in defining a grammar where the sequence
<CRLF><CRLF> has a different meaning than <CRLF><SPACE><CRLF>.
...

Interesting.  I don't think that is a problem with the grammar,
and think it would be rather hard to define a grammar that would
not permit that situation.   After all
    <CRLF> Thing <SPACE><CRLF> could case similar problems if
some construction permitted it and defining a grammar that would
prohibit any <SPACE><CRLF> construction isn't easy in ABNF for
reasons that have nothing to do with LWSP.

Instead, I see the problem as using the grammar to define
situations equivalent to 
    LWSP [ optional-stuff ] CRLF
as compared to 
    LWSP AtLeastOneRequiredThing CRLF
or
    [ LWSP optional-stuff ] CRLF

I don't see either of the latter as problematic.

      john






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