At 9:43 AM +0000 11/19/03, Adam M. Costello wrote:
> Note that the idea was to allow signature separator lines to be
> quoted, but not stuffed unless also quoted.
I failed to notice that subtlety. Hmmm, are you sure that's what you
want? That would be the only place where quoting and stuffing are not
orthogonal.
True, but then signature separator lines are a weird anomaly anyway.
The RFC 2646 ABNF rules are clear that signature separator lines
can't be stuffed unless they are also quoted, so I just carried that
forward in the update.
It looks like it might be asking for trouble. Consider
this format=flowed message body:
Foo
--
bar.
The first two lines end with a space, and the third does not. According
to your definition of separator lines, this is a single paragraph,
because the middle line is a flowed line, not a separator line. But
what happens if I try to quote that paragraph by inserting a quote
indicator before each line:
Foo
--
bar.
According to your definition of separator lines, this is now an invalid
format=flowed message body, because it contains a flowed line followed
by a separator line.
True, but it would be rather foolish for a client to generate such a
thing. Why would it choose to wrap immediately before and after a
SPACE DASH DASH SPACE sequence?
> The suggested definitions for flowed lines attempt to eliminate the
ambiguity between a flowed line and a signature separator but I don't
think they allow for all cases of flowed lines.
I wouldn't be surprised if I made a mistake in that tricky part of the
grammar, but can you produce a concrete example of a line that ought to
be flowed and doesn't match my suggested flowed-line production? That
would be the surest way to expose the problem.
It's also possible that the grammar is correct, but structured in a
confusing way. If that's the case, I welcome suggestions for less
confusing ways of expressing the same syntax.
For convenience, here's another copy of the relevant parts of the
grammar that I suggested:
flowed-line = quote (stuff stuffed-flowed / unstuffed-flowed) flow CRLF
stuffed-flowed = [non-dash *text-char] /
"-" [non-dash *text-char / "-" 1*text-char]
; Is not "--".
unstuffed-flowed = non-sp-quote-dash *text-char /
"-" [non-dash *text-char / "-" 1*text-char]
; Not empty, not "--", does not begin with SP or ">".
quote = *">"
stuff = SP
flow = SP
I think it's a good idea to use parentheses to explicitly group the
ABNF constructs, to avoid confusion. RFC 2234 recommends this as
well.
So, taking your suggested 'unstuffed-flowed' to be
unstuffed-flowed = ( non-sp-quote-dash *text-char ) /
( "-" [non-dash *text-char ) /
( "-" 1*text-char] )
I think DASH DASH would match the third alternative for this
'unstuffed-flowed', since the first DASH matches the "-" and the
second DASH matches text-char, and only one text-char is required.
So a line of DASH DASH SPACE would match 'flowed-line'.
--
Randall Gellens
Opinions are personal; facts are suspect; I speak for myself only
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The well-bred contradict other people. The wise contradict themselves.
--Oscar Wilde