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

[Brian Rosen <[e-mail]>]

Gunnar

And yet you persist.

We have agreed NOT to do preferences between modalities.  Any suggestion that we do so is out of scope for this document.  If you want to write a draft that extends the mechanism, please do and I’ll review it, but PLEASE don’t keep suggesting that we handle preferences between media in this document.  We agreed NOT to do it.

I would prefer the current syntax, and not Accept-Language syntax.

Brian

> On Jun 1, 2017, at 2:01 PM, Gunnar Hellström <[e-mail]> wrote:
> 
> Den 2017-06-01 kl. 19:17, skrev Randall Gellens:
>> The group has repeatedly discussed q-values and priority and has always decided to not go down that path.
> I expect our shepherd to lead us to the decision. We had one reviewer requesting us to use the Accept-Language syntax with the q-values.
> 
> I can accept either way, either the one-line syntax used in version -10, or the Accept-Language syntax.
> 
> If we go with the current one-line syntax, I will propose to add the preference between modalities by giving the asterisk a preference interpretation on media level.
> And I will propose to use the -t language subtag for simultaneous languages in other modalities.
> This may lack some flexibility but will likely be sufficient.
> 
> If we go with the Accept-Language syntax, then I will propose to let the q-values have scope over the whole SDP in order to assign preference between modalities,
> and I will propose to let equal q-values or q-values within a narrow interval to indicate a preference for using simultaneous languages in different media. The first item is nice and flexible, the second, for simultaneity may be less elegant.
> 
> I hope you will accept either solution. And do it already in the current draft.
> 
> So we just need the decision on the Accept-Language syntax proposal and then move on.
> 
> Regards
> 
> Gunnar
> 
> 
> 
> 
> 
> 
>> 
>> 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: ---------------
>>>>> Knowledge always desires increase; it is like fire, which must
>>>>> first be kindled by some external agent, but which will afterwards
>>>>> propagate itself. --Dr. Samuel Johnson
>>>>> 
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>>> 
>>> --
>>> -----------------------------------------
>>> Gunnar Hellström
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> 
> -- 
> -----------------------------------------
> Gunnar Hellström
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