Support FILTER (lang(?label) = "en") and fix langMatches()

[niklas88]

We should support the standard

FILTER (lang(?label) = "en")

Instead of only

FILTER langMatches(lang(?label), "en")

which is also slightly wrong as it should match also "en-ca", "en-us" and so on.

[floriankramer]

@niklas88 Do we need support for langMatches? implementing FILTER (lang(?label) = "en") is trivial.
langMatches would probably need additional index structures, as we would need to be able to match language ranges, and collections of language ranges. A language range is any prefix of a language tag, where the range contains the tag only if the range is a prefix of the tag, and the character after the prefix is "-" (according to RFC3066 paragraph 2.5)

[niklas88]

I'm currently sick which is why I've been quiet. I think for now it's ok to just support the lang Syntax and either don't support langMatches() at all or keep it broken as is. I meant to talk to you about * paths (maybe as a fixed limit as a first step) which are really important for Wikidata. Hopefully, I'll be back to working order on ThursdayOn Apr 2, 2019 16:48, Florian Kramer <notifications@github.com> wrote:@niklas88 Do we need support for langMatches? implementing FILTER (lang(?label) = "en") is trivial. langMatches would probably need additional index structures, as we would need to be able to match language ranges, and collections of language ranges. A language range is any prefix of a language tag, where the range contains the tag only if the range is a prefix of the tag, and the character after the prefix is "-" (according to RFC3066 paragraph 2.5) —You are receiving this because you were mentioned.Reply to this email directly, view it on GitHub, or mute the thread.

[niklas88]

fixed in #223