Re: [Slim] Collapse attribute syntax to one line in draft-ietf-slim-negotiating-human-language

[Randall Gellens <[e-mail]>]

The group has repeatedly discussed q-values and 
priority and has always decided to not go down 
that path.

At 4:33 PM +0200 6/1/17, Gunnar Hellström wrote:

>  Den 2017-06-01 kl. 11:54, skrev Natasha Rooney:
>
>>  This seems sufficient given our previous 
>> conversations. q-values can be applied within 
>> further work (although I don't see why 
>> ordering doesn't do the job, works in web).
>>
>  It is not feasible to change syntax by adding 
> q-values in an extension. That will cause 
> interop problems, or complicated needs to 
> negotiate protocol version. So, we need to 
> decide the syntax now and stick closely to it.
>
>  Ordering is not sufficient because we have a 
> need to set preferences between different media.
>  Ordering only works within a media.
>
>  And, a minor drawback: ordering does not allow 
> to specify a number of languages in the same 
> media with the same preference. One always will 
> look as if it is more preferred than another. - 
> but I think we can live with that.
>
>  Maybe the main question is: Will our own 
> one-line syntax really be less complex to parse 
> than the Accept-Language syntax that we might 
> be able to find ready library routines for?
>  Adam Roach had views on complexity to parse 
> different solutions. Maybe you, Adam can have a 
> view on this?
>
>  Regards
>
>  Gunnar
>
>>
>>  Bernard - any further thoughts?
>>
>>
>>  Natasha Rooney | Internet Engineering Director 
>> | Internet and Web Team | Technology | GSMA | 
>> <mailto:[e-mail]>[e-mail] | 
>> [phone] | @thisNatasha | Skype: 
>> <mailto:[e-mail]>[e-mail]
>>
>>>  On 30 May 2017, at 00:04, Randall Gellens 
>>> <<mailto:[e-mail]>[e-mail]> 
>>> wrote:
>>>
>>>  I uploaded version -10, which includes the 
>>> syntax change to single line, along with a 
>>> few editorial clarifications. (Version -09 
>>> accidently omitted an editorial 
>>> clarification.)
>>>
>>>  You can see a diff of the changes from 08 to 10 here:
>>> 
>>> <https://www.ietf.org/rfcdiff?url1=draft-ietf-slim-negotiating-human-language-08&url2=draft-ietf-slim-negotiating-human-language-10>https://www.ietf.org/rfcdiff?url1=draft-ietf-slim-negotiating-human-language-08&url2=draft-ietf-slim-negotiating-human-language-10
>>>
>>>  If there objections to the change from 
>>> multi-line to single-line, this can be 
>>> reverted.
>>>
>>>  --Randy
>>>
>>>
>>>
>>>  At 2:57 PM -0700 5/28/17, Randall Gellens wrote:
>>>
>>>>  In response to Adam Roach's comments as well 
>>>> as other comments, I intend to update the 
>>>> draft to collapse the attribute syntax to 
>>>> one line; each attribute can occur at most 
>>>> once per media, with all languages on the 
>>>> same line. This will further reduce the size 
>>>> of the SDP block.
>>>>
>>>>  If you object to this, please reply.
>>>>
>>>>  Here is the section of Adam's review:
>>>>
>>>>  At 8:31 PM +0000 3/28/17, Sabrina Tanamal via RT wrote:
>>>>
>>>>>  I'll note that much of this can be fixed if the syntax is collapsed so
>>>>>  that each media section can have at most one hlang-send and one
>>>>>  hlang-receive, each of which contain a list of one or more languages
>>>>>  that can be sent or received. This is also much more consistent with the
>>>>>  way SDP attributes are used in general. The presence of a "*" token on
>>>>>  that line would indicate the "call should happen even without matching
>>>>>  languages" characteristic; since there is only one place to add this
>>>>>  indicator, the ambiguity of some lines indicating it and others not
>>>>>  disappears. The preceding example would collapse to:
>>>>>
>>>>>  m=audio 49250 RTP/AVP 20
>>>>>  a=hlang-send:es eu en *
>>>>>  a=hlang-recv:es eu en *
>>>>>
>>>>>  ...and the example text would be revised to remove the implication that
>>>>>  *sending* "es" necessarily implies *receiving* "es".
>>>>>
>>>>>  I'll further note that the majority of SDP libraries I've worked with
>>>>>  would make accessing the all-on-one-line format easier than
>>>>>  one-line-per-language as well.
>>>>>
>>>>
>>>>  Here is the proposed ABNF:
>>>>
>>>>  Attribute Syntax:
>>>>
>>>>  hlang-value = Language-Tag *( SP Language-tag ) [ SP asterisk ]
>>>>
>>>>  ; Language-Tag as defined in BCP 47
>>>>
>>>>  asterisk = "*" ; an asterisk (ASCII %2A) character
>>>>
>>>>  sp = 1*" " ; one or more ASCII space (%20) characters
>>>>
>>>>  --
>>>>  Randall Gellens
>>>>  Opinions are personal; facts are suspect; I speak for myself only
>>>>  -------------- Randomly selected tag: ---------------
>>>>  If forced to travel on an airplane, try and get in the cabin with
>>>>  the Captain, so you can keep an eye on him and nudge him if he
>>>>  falls asleep or point out any mountains looming up ahead ...
>>>>  --Mike Harding, The Armchair Anarchist's Almanac.
>>>>
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>>>
>>>
>>>  --
>>>  Randall Gellens
>>>  Opinions are personal; facts are suspect; I speak for myself only
>>>  -------------- Randomly selected tag: ---------------
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>>>  first be kindled by some external agent, but which will afterwards
>>>  propagate itself. --Dr. Samuel Johnson
>>>
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>
>  --
>  -----------------------------------------
>  Gunnar Hellström
>  Omnitor
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-- 
Randall Gellens
Opinions are personal;    facts are suspect;    I speak for myself only
-------------- Randomly selected tag: ---------------
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