Re: [MMUSIC] A bug in SDP Syntax (CRLF)?

[Colin Perkins <csp@isi.edu>]

--> "Federico Montesino Pouzols" writes:
>>>        An implementor would have to choose between strictly
>>>applying the ABNF or being tolerant with single LFs.
>>>
>>>         Should not -at least- a note be added to the ABNF clarifying
>>>this exception?
>>
>> No. A correct implementation will use CRLF in all cases, and the ABNF
>> reflects this. Using a single LF to terminate lines is a bug.
>
>   Then I infer that if I am doing a new implementation and I want it
>to be compliant with the specification I must always use CR LF and
>consider single LFs as a mistake. All the lines in the SDP
>descriptions generated by the new implementation must end with CR LF
>and my new parser must not accept descriptions with lines ending with
>a single LF?
>
>   This new implementation would follow the ABNF, however it would
>also cowardly ignore the _"although parsers SHOULD be tolerant and also
>accept records terminated with a single newline character"_ in section
>6.
>
>   Using a LF to terminate lines may not be strictly correct, but the
>specification recommends (SHOULD) parsers to be tolerant about it. So
>I think it would be clearer for implementors if the ABNF syntax
>mentioned this exception as a note or whatever.
>
>   From my point of view and my understanding of the draft, an
>implementation that in all cases only accepts CR LF is correct in some
>sense but would be incorrect at the same time, since it ignores the
>quoted sentence in the draft and RFC. In fact, it would reject a lot
>of SDP descriptions and could not interoperate with many tools out
>there.

SDP descriptions where the lines end in a single LF are incorrect. You may
wish to design your parser such that it accepts them anyway - as suggested
by the draft - but there is no requirement that you do this, and you could
reject such descriptions.

Colin

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