Multiple language tag strings vs OSLC property cardinality

[berezovskyi]

@frejfrej reported that certain Jazz ETM shapes have OSLC Shape Property definitions with more than one title (one without a language tag and multiple tagged with different language tags).

[berezovskyi]

We should make use of https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept-Language to let users indicate the subset of languages they are interested in to keep the response short.

[DavidJohnHoney]

I think the original intent is that for any string property with a maximum cardinality of 1 that:

1. There should be a maximum of one plain-literal value
2. For language tagged literals, there should be a maximum of one such value for any given language.

Example of valid usage:
Property name has dcterms:title with plain literal, plus one English tagged literal, plus one French tagged literal, plus one German tagged literal.

Examples of invalid usage:
Property name as dcterms:title with two plain literal values.
Property name as dcterms:title with two plain French tagged literal values.

[DavidJohnHoney]

However, there are some other concerns:
For shape names and property names, the spec says XMLLiteral. That would preclude the use of palin literals or language tagged literals.

[berezovskyi]

See https://www.w3.org/TR/shacl/#UniqueLangConstraintComponent

[berezovskyi]

@frejfrej please feel free to report technical details on eclipse-lyo/lyo#261