Remove Natural Language Value

[jasnell]

See: http://lists.w3.org/Archives/Public/public-socialweb/2014Nov/0010.html

"The "Natural Language Value" construct in AS2 was originally added
before the serialization of AS2 was formally based on JSON-LD. The
mechanism is intended to provide a default language context for the
document, but it's not entirely compatible with the JSON-LD mechanisms
and requires a pre-processing step to be implemented before successful
JSON-LD processing... At this point, I think it makes sense to simply remove the Natural
Language Value construct and rely specifically on the JSON-LD
mechanisms to eliminate the additional pre-processing step. Doing so
makes things a bit more reliant on JSON-LD but simplifies things
overall."

[jasnell]

Related to #21

[jasnell]

Due to the way @language works within JSON-LD, there are a couple of gotchas in the way AS 2.0 is currently defined. The original goal was to make it so that a single "language sensitive" property like "displayName" could be either a literal string or a language-map... e.g.

{
  "displayName": "Foo"
}

or

{
  "displayName": {
    "en": "Foo",
    "fr": "Bar"
  }
}

This has advantages and disadvantages. One key disadvantage is that it simply does not work properly in JSON-LD without additional processing. The correct JSON-LD approach would be to map distinct terms in the JSON-LD @context, e.g.

{
  "@context": {
    ...,
    "displayName": "as:displayName",
    "displayNameMap": {
      "@id": "as:displayName",
      "@container": "@language"
    },
    "title": "as:title",
    "titleMap": {
      "@id": "as:title",
      "@container": "@language"
    },
    ...
  }
}

When run through the JSON-LD algorithms, things just work as expected. In the serialized compacted JSON-LD... the choices become:

{
  "displayName": "Foo"
}

and

{
  "displayNameMap": {
    "en": "Foo",
    "fr": "Bar"
  }
}

The advantage here is that "displayName" is always just a literal string, whereas "displayNameMap" is always a Language Map. It requires us to track one additional term for each language-sensitive field, but the advantage is greater consistency and less weirdness. Which is always good

[jasnell]

Covered by current Editor's draft