Markus Krötzsch, 04/08/2013 17:35:
Are you sure? The file you linked has mappings from site ids to language codes, not from language codes to language codes. Do you mean to say: "If you take only the entries of the form 'XXXwiki' in the list, and extract a language code from the XXX, then you get a mapping from language codes to language codes that covers all exceptions in Wikidata"?
Yes. You said Wikidata just uses the subdomain and the subdomain is contained in the database names used by the config. Sorry if I implied the removal of the wik* suffix and the conversion from _ to -
This approach would give us:
'als' : 'gsw', 'bat-smg': 'sgs', 'be_x_old' : 'be-tarask', 'crh': 'crh-latn', 'fiu_vro': 'vro', 'no' : 'nb', 'roa-rup': 'rup', 'zh-classical' : 'lzh' 'zh-min-nan': 'nan', 'zh-yue': 'yue'
Each of the values on the left here also occur as language tags in Wikidata, so if we map them, we use the same tag for things that Wikidata has distinct tags for. For example, Q27 has a label for yue but also for zh-yue [1]. It seems to be wrong to export both of these with the same language tag if Wikidata uses them for different purposes.
Maybe this is a bug in Wikidata and we should just not export texts with any of the above codes at all (since they always are given by another tag directly)?
Sorry, I don't know why both can appear. I would have said that one is a sitelink and the other some value added on wiki with the correct language code (entry label?) but my limited json reading skills seem to indicate otherwise.
[...]
Well, the obvious: if a language used in Wikidata labels or on Wikimedia sites has an official IANA code [2],
(And all of them are supposed to, except rare exceptions with pre-2006 wikis.)
then we should use this code. Every other code would be "wrong". For languages that do not have any accurate code, we should probably use a private code, following the requirements of BCP 47 for private use subtags (in particular, they should have a single x somewhere).
This does not seem to be done correctly by my current code. For example, we now map 'map_bmswiki' to 'map-bms'. While both 'map' and 'bms' are lANA language tags, I am not sure that their combination makes sense. The language should be Basa Banyumasan, but bms is for Bilma Kanuri (and it is a language code, not a dialect code). Note that map-bms does not occur in the file you linked to, so I guess there is some more work to do.
Indeed, that appears to be one of the exceptions. :) I don't know how it should be tracked, you could file a bug in MediaWiki>Internationalisation asking to find a proper code for this language. What was unclear to me is why you implied there were many such cases; that would surprise me.
Nemo