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Atoms and phrases (Was: UTF-8 in headers)

1999-02-04 15:05:22
I have Bcc'ed this message to ietf-822(_at_)imc(_dot_)org since this discussion originated there, but have directed the discussion to DRUMS, since this is a DRUMS issue. Please direct future followup on this subtopic to the DRUMS list.

On 2/4/99 at 2:23 PM -0500, Keith Moore wrote:

I think not. I was working from the syntax in DRUMS (admittedly my version was dated March 1998, so it may be different now). The syntax I have gives:

atom = [CFWS] 1*atext [CFWS]

so "foo" and "bar" are atoms (the CFWS is optional).

This probably points to a need for a clarification in DRUMS -
an atom is intended to be the entire contiguous sequence of
so "foobar" is a phrase consisting of two words side-by-side, as allowed by the syntax. It can also be legitimately parsed in many other ways, of course.

this may be allowed by the grammar, but was not intended.

It was not intended. Back in draft -05, there was a sentence in the syntax discussion of the atom definition that said "Two atoms have to be separated by some other token, since putting two atoms next to each other would create a single atom." It was pointed out to me that this was incorrect, since the atom token itself includes the optional CFWS, so I removed the sentence. However, in the semantics description of atom, it says: "Semantically, the optional comments and FWS surrounding the rest of the characters are not part of the token; the token is only the run of atext characters in an atom..."

If further clarification is needed in the atom definition, or in the definition of phrase, to disambiguate, I'm open for suggestions.

Pete Resnick <mailto:presnick(_at_)qualcomm(_dot_)com>
Eudora Engineering - QUALCOMM Incorporated
Ph: (217)337-6377 or (619)651-4478, Fax: (619)651-1102

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