Module:WikidataIdentifiers

-- Functions for use in retrieving Wikidata for use in templates that deal with identifiers

-- getIdentifierQualifier returns the value of a qualifier for an Identifier

p = {}

-- getIdentifierQualifier returns the value of a qualifier for an Identifier

-- such as 'Art UK artist ID', P1367

-- the assumption is that one value exists for the property

-- and only one qualifier exists for that value

-- Constraint violations for P1367 are at:

-- https://www.wikidata.org/wiki/Wikidata:Database_reports/Constraint_violations/P1367#Single_value

p.getIdentifierQualifier = function(frame)

local propertyID = mw.text.trim(frame.args[1] or "")

-- The PropertyID of the qualifier

-- whose value is to be returned is passed in named parameter |qual=

local qualifierID = frame.args.qual

-- Can take a named parameter |qid which is the Wikidata ID for the article.

-- This will not normally be used because it's an expensive call.

local qid = frame.args.qid

if qid and (#qid == 0) then qid = nil end

local entity = mw.wikibase.getEntityObject(qid)

local props

if entity and entity.claims then

props = entity.claims[propertyID]

end

if props then

-- Check that the first value of the property is an external id

if props[1].mainsnak.datatype == "external-id" then

-- get any qualifiers of the first value of the property

local quals = props[1].qualifiers

if quals and quals[qualifierID] then

-- check what the dataype of the first qualifier value is

-- if it's quantity return the amount

if quals[qualifierID][1].datatype == "quantity" then

return tonumber(quals[qualifierID][1].datavalue.value.amount)

end

-- checks for other datatypes go here:

end

end

end

end

return p