Format=Flowed/RFC 2646 Bis (-04)

[Randall Gellens]

I've created an -04 based on the additional comments received in the
past few days.

Changes from -03 to -04:

* Clarified and made consistent treatment of signature separator lines.
* Fixes to ABNF.
* Reworded section on digital signatures and encryption.
* Noted meaning of "paragraph".

The updated text is available at
<ftp://ftp.pensive.org/Public/Randy/draft-gellens-format-bis-04.txt>

Changes from -02 to -03:

* Added mention of quoting to Abstract and Introduction.
* Deleted line analysis table.
* Added MUST NOT for OpenPGP and SHOULD for OpenPGP-MIME.
* Replaced ABNF rules to remove ambiguity
* Added note that c-t-e is irrelevant to flowed text processing
* Added text indicating that end of data terminates a paragraph
* Moved sig-sep out of fixed-line ABNF
* Changed some SHOULDs to MUSTs (space-stuffing, quoted paragraphs)
* Added note to ABNF that space and ">" are encoded according to charset
* Mentioned exceptions in section on interpreting
* Moved section on interpreting before section on generating.
* Reworded non-normative "should"s.

--
Randall Gellens
Opinions are personal; facts are suspect; I speak for myself only
-------------- Randomly-selected tag: ---------------
Frequently, people can tell you they've read a book and
liked it, but they can't tell you why. We don't want the
reader to have to do the hard work of figuring that out.
--Duncan Smith, creator of NoveList.

[Simon Josefsson]

Has anyone collected test vectors for format=flowed? Considering the
amount of buggy implementations, I believe it would be useful to have
these available. I'm writing a test harness for my implementation, so
I'd appreciate any pointers to existing test vectors I could adopt.

To give one (to me) problematic example, how to render this:

> foo foo foo foo foo foo foo foo foo foo foo foo foo foo foo foo foo foo foo
> foo
>
>
>
> foo foo foo foo foo foo foo foo foo foo foo foo foo foo foo foo foo foo foo
> bar

Thanks,
Simon

[Charles Lindsey]

Opera rendered it (no extra '>'s added) as

--------------------------

>foo foo foo foo foo foo foo foo foo foo foo foo foo foo foo foo foo foo foo foo
> foo foo foo foo foo foo foo foo foo foo foo foo foo foo foo foo foo foo foo
>bar

Thanks,
Simon

--------------------------

I have left the trailing spaces in, because this message is not
format=flowed, so you SHOULD NOT be reflowing it.

--
Charles H. Lindsey ---------At Home, doing my own thing------------------------
Tel: +44 161 436 6131 Fax: +44 161 436 6133 Web: http://www.cs.man.ac.uk/~chl
Email: c...@clerew.man.ac.uk Snail: 5 Clerewood Ave, CHEADLE, SK8 3JU, U.K.
PGP: 2C15F1A9 Fingerprint: 73 6D C2 51 93 A0 01 E7 65 E8 64 7E 14 A4 AB A5

[Adam M. Costello]

Charles Lindsey <c...@clerew.man.ac.uk> wrote:

> Opera rendered it...

The lines consisting of just a greater-than sign and a space are fixed,
right? (Because the space is a stuffing space.) So there should be two
separate quoted "foo foo foo..." paragraphs separated by quoted blank
lines, right?

AMC

[Simon Josefsson]

I dunno. -04 also says:

If the line ends in a space, the line is flowed. Otherwise it is
fixed. The exception to this rule is a signature separator line,
described in Section 5.3. Such lines end in a space but are neither
flowed nor fixed.

This suggest the line is flowed.

Also of relevance may be that the document considers

> foo

and

>foo

to be logically the same during encoding. I'm not sure if the lines
are still considered equivalent if the 'foo' is removed from both of
them.

It is also not clear if the DELSP parameter should modify the output
for this example. I.e., is the SPC a stuffing or trailing SPC? The
Opera output quoted by Charles Lindsey did not appear to remove the
trailing SPC when flowing lines together, but presumably it implement
RFC 2646 and not draft-gellens-format-bis-04.txt. Having different
behaviour in 2646 and 2646bis might not be ideal either.

Pseudo code for a correct decoder would make matters simpler...

Thanks,
Simon

[Adam M. Costello]

Simon Josefsson <simon+i...@josefsson.org> wrote:

> > The lines consisting of just a greater-than sign and a space are fixed,
> > right? (Because the space is a stuffing space.)
>

> I dunno. -04 also says:
>
> If the line ends in a space, the line is flowed. Otherwise it is
> fixed.
>

> This suggest the line is flowed.

The sentences immediately preceeding that one are:

If the first character of a line is a space, the line has been
space-stuffed (see section 5.4). Logically, this leading space is
deleted before examining the line further (that is, before checking
for flowed).

AMC