On Fri, 18 May 2007, John C Klensin wrote:
On Friday, 18 May, 2007 09:00 +0100 Tony Finch <dot(_at_)dotat(_dot_)at>
wrote:
NTWSP = [CRLF] 1*WSP ; non-trailing white space
Sure. Except that much, if not most, of our textual
descriptions of these protocols describes lines, and line-like,
constructions as _ending_ in CRLF. Moving to "starting in
CRLF" creates a conceptual difference between prose definition
and formal syntax, which strikes me as a bad idea.
Don't do that then. The suggestion I made above was for a no-trailing-
whitespace variant of 2822's FWS, and as such it would be used in a
grammar inside a logical line, not at either end. You seem to be inventing
problems that might occur in badly-designed grammars, and as such these
are bugs in the grammars and not due to limitations of ABNF (which, after
all, is equivalent to any other notation for describing context-free
grammars).
Of course, in the above, since [CRLF] is optional, "1*WSP" alone
satisfies the production as written and still does not prevent
<CRLF> space space space
<CRLF>
Um, no, because WSP = SP / HTAB
Tony.
--
f.a.n.finch <dot(_at_)dotat(_dot_)at> http://dotat.at/
SOUTHEAST ICELAND: CYCLONIC, BECOMING NORTHERLY GALE 8 OR SEVERE GALE 9,
DECREASING 6 OR 7. ROUGH OR VERY ROUGH, OCCASIONALLY HIGH. SHOWERS. MODERATE
OR GOOD.
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