Subject: Re: [Sip] Some more ABNF issues - bis07

From: Bill Fenner <[email-masked]>
Date: Wed, 6 Feb 2002 15:12:03 -0800

So, this may seem a little weird, but I wrote my own ABNF parser 
and ran the bis07 ABNF through it, and came up with another couple of
fairly subtle issues:

- "word" is missing slashes between "~" and "(", and between ">" and ":".
  This makes these elements concatenate, i.e.
  ... "'" / ( "~" "(" ) / ")" / "<" / ( ">" ":" ) / "\" / <">  ...
  which is clearly bad.

- Similar precedence issue: concatenation binds more tightly than
  alternation, so despite the whitespace, you need a grouping
  around the second line of Contact:

  Contact        =  ("Contact" / "m" ) HCOLON
                    STAR / (contact-param *(COMMA contact-param))

  else it really means
  (("Contact" / "m" ) HCOLON STAR) / (contact-param *(COMMA contact-param))

These were the only two problems that this new tool caught that I don't
think have been mentioned yet.

Also, I'm sure this is redundant by now, but to continue earlier thoughts
on representing the double quote character, there's a DQUOTE element in
the ABNF core that can be used instead of <"> or %x22 .

  Bill

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---

From: Jonathan Rosenberg <[email-masked]>
Date: Mon, 18 Feb 2002 20:33:56 -0500

>   This makes these elements concatenate, i.e.

Yikes, good catch there. Fixed.

>   (("Contact" / "m" ) HCOLON STAR) / (contact-param *(COMMA

Another excellent catch. Fixed.

> the ABNF core that can be used instead of <"> or %x22 .

OK, that sounds like the best plan. I changed to DQUOTE.

-Jonathan R.
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