Re: WGLC on draft-ietf-mmusic-sdp-simulcast-07
[email protected] (Dale R. Worley)
| Newsgroups | gmane.ietf.mmusic |
|---|---|
| Message-ID | <[email protected]> |
Iñaki Baz Castillo <[email protected]> writes: >> but according to https://tools.ietf.org/html/draft-ietf-mmusic-rid-09 >> it seems that "direction" (send/recv) should be placed *before* >> "pt=xx": >> >> a=rid:<rid-id> <direction> [pt=<fmt-list>;]<restriction>=<value>... > > In fact, pt=xx seems to be yet another "param". That purported BNF is really bizarre, since it generates the clearly incorrect form: a=rid:<rid-id> <direction> <restriction>=<value><restriction>=<value> A correct description is: a=rid:<rid-id> <direction> ( pt=<fmt-list> | <restriction>=<value> ) *( ; <restriction>=<value> ) The problem is that BNF doesn't allow you to directly specify what you want to say: (1) pt is like a parameter, but if it's present, it must be first, and (2) there must be at least one pt or restriction. And there's no simple construction for "a list of one or more X's separated by Y's". Dale _______________________________________________ mmusic mailing list [email protected] https://www.ietf.org/mailman/listinfo/mmusic