On May 15, 2007, at 10:16 AM, John Leslie wrote:
I did some research, and found the following mentions of LWSP:
rfc0733 obs-by rfc0822
rfc0822 defs LWSP-char = SPACE / HTAB obs-by rfc2822
rfc0987 refs rfc0822
rfc1138 refs rfc0822
rfc1148 refs rfc0822
rfc1327 refs rfc0822
rfc1486 refs rfc0822
rfc1505 refs rfc0822
rfc1528 refs rfc0822
rfc1848 defs <LWSP-char> ::= SPACE / HTAB
rfc2017 refs rfc0822
rfc2045 refs rfc0822
rfc2046 refs rfc0822
rfc2110 refs rfc0822
rfc2156 refs rfc0822
rfc2184 refs rfc0822
rfc2231 refs rfc0822
rfc2234 defs LWSP = *(WSP / CRLF WSP) obs-by rfc4234
rfc2243 refs rfc0822
rfc2378 defs LWSP-char = SP | TAB
rfc2530 refs rfc2234
rfc2885 defs LWSP = *(WSP / COMMENT / EOL)
rfc3015 defs LWSP = *(WSP / COMMENT / EOL)
rfc3259 defs LWSP = *(WSP / CRLF WSP)
rfc3501 refs rfc2234
rfc3525 defs LWSP = *(WSP / COMMENT / EOL)
rfc3875 defs LWSP = SP | HT | NL
rfc4234 defs LWSP = *(WSP / CRLF WSP)
rfc4646 refs rfc2434
Based on this, I recommend outright deprecation. The RFC4234
definition is wildly different from the RFC822 usage (which is
substanitally more often referenced): thus any use of it will tend
to confuse. It's also a bit dubious, quite specifically allowing
lines which appear to be blank, but aren't. :^(
The RFC4234 definition, in fact, is referenced by only 3 RFCs:
RFC2530 Indicating Supported Media Features Using Extensions to DSN
and MDN
RFC3501 INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1
RFC4646 Tags for Identifying Languages
The use under RFC2530 is a bit vague ("with LWSP wrapping");
likewise
under RFC3501 ("otherwise treat SP as being equivalent to LWSP"). The
use under RFC4646 has caused known problems.
This would seem to justify deprecation, IMHO.
Agreed.
From a standards standpoint, half a dozen definitions for an ABNF
mnemonic is absurd.
Perhaps something like:
The LWSP mnemonic has been deprecated and should not be used in
future drafts. Explicit definitions based upon different mnemonics
should be used instead. If possible, syntax should guard against
possible security concerns related to visual deceptions.
-Doug
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