Re: social-ISSUE-14 (elf-pavlik): as:Link adds a lot of complexity, if we keep it we need to clarify consequences of using it instead of as:Object [Activity Streams 2.0]

On 02/23/2015 02:19 PM, Social Web Working Group Issue Tracker wrote:
> social-ISSUE-14 (elf-pavlik): as:Link adds a lot of complexity, if we keep it we need to clarify consequences of using it instead of as:Object [Activity Streams 2.0]
> 
> http://www.w3.org/Social/track/issues/14
> 
> Raised by: Pavlik elf
> On product: Activity Streams 2.0
> 
> This continues discussion in two github issues
> * as:Link from Linked Data perspective + comparing with hydra:Link - https://github.com/jasnell/w3c-socialwg-activitystreams/issues/24
> 
> * clarify consequences of choice between as:Object and as:Link - https://github.com/jasnell/w3c-socialwg-activitystreams/issues/57
> 
> Main issues I noticed so far:
> 
> 1. AS2.0 Vocabulary uses Object | Link for domain and/or range in many properties
> http://www.w3.org/TR/2015/WD-activitystreams-vocabulary-20150129/ (search for 'Object | Link' shows 43 such cases)
> 
> 2. Currently some examples in latest published core spec use as:Link in JSON-LD while as:Object in RDFa (IMO it gives strong example of confusion it may cause, even author of the spec didn't use it in a consistent way!)
> http://www.w3.org/TR/2015/WD-activitystreams-core-20150129/#example-2
> 
> 3. as:Link breaks JSON-LD embedding
> http://www.w3.org/TR/json-ld/#embedding
> and may cause issue with JSON-LD framing
> http://json-ld.org/spec/latest/json-ld-framing/ (work in progress)
> 
> To stay honest, I don't see strong use cases requiring as:Link which would justify adding all this complexity and possibilities for confusion. Still if we decide to keep it, we should explain clearly when to use as:Link and when as:Object, elaborating on various consequences of making such choice.
I suggested quick overview of this issue during today's telecon
* https://www.w3.org/wiki/Socialwg/2015-03-10

As well as during our face 2 face
* https://www.w3.org/wiki/Socialwg/2015-03-17

James, could you help with clarifying few aspects of as:Link


1. how does as:Link relate to httpRange-14?
* http://en.wikipedia.org/wiki/HTTPRange-14
* https://www.w3.org/wiki/HttpRange14Webography

Looking at examples in AS2.0 Core
* http://www.w3.org/TR/activitystreams-core/#link

It looks like you mostly use it for media types of the image files as
well as available width and height variants. I created an action for
MediaObject to look at other ways to covering this functionality.
* https://www.w3.org/Social/track/actions/42
ACTION-42: MediaObject - gather options for its social syntax on a wiki page


2. how does as:Link relate to use of link relations in JSON-LD?
In AS2.0 core spec you have example using "rel": "canonical"
AS2.0 vocab defines it as "An RFC 5988 Link Relation associated with a Link"
* http://www.w3.org/TR/activitystreams-vocabulary/#dfn-rel

As you know we have issue on github started by Erik very relevant to use
of link relations, especially with JSON-LD
* https://github.com/mnot/I-D/issues/39


3. how does it relate to suggesting dereferenceability?
People in Hydra CG took quite some time to discuss various aspects of
that problem
* https://github.com/HydraCG/Specifications/issues/91
AS2.0 Core doesn't mention dereferenceability anywhere except paragrahp
clarifying IRI/URI.



IMO we may try to solve to many different problems with as:Link
construct. In the end we may end up with situation where different AS2.0
producers use different modeling pattern for expressing exactly the same
concepts. IMO it will make both producing and consuming AS2.0 much more
complex. Producers will need to decide which slang they want to use or
try to combine multiple ones. Consumers may need to try to interpret
multiple slangs of AS2.0 since the same conceptual data can have
different way of expressing using AS2.0 model.

Thank you for helping with further clarifying motivation behind and
purpose of as:Link.

Cheers!