Module:Wikidata statements

Documentatie voor deze module kan aangemaakt worden op de volgende pagina: Module:Wikidata statements/doc

-- =============================================================================
-- Routines for accessing statements from Wikidata
-- =============================================================================

local p = {}

-- -----------------------------------------------------------------------------
-- Return information about a statement, usable for error messages
-- -----------------------------------------------------------------------------

local function statementInfo(statement)
	return (
		"Item " .. string.match(statement.id, "^(.*)%$")
		.. ", Property " .. statement.mainsnak.property
	)
end

-- -----------------------------------------------------------------------------
-- Return the item id for a statement that points to a data item
-- -----------------------------------------------------------------------------

local function getAnyId(statement, datatype, entitytype)
	assert(
		statement.mainsnak.datatype == datatype,
		statementInfo(statement) .. " is not of datatype " .. datatype
	)
	local datavalue = assert(
		statement.mainsnak.datavalue,
		statementInfo(statement) .. " has no datavalue"
	)
	assert(
		datavalue.type == "wikibase-entityid",
		statementInfo(statement) .. "'s value is not of type wikibase-entityid"
	)
	local value = assert(
		datavalue.value,
		statementInfo(statement) .. " has no value"
	)
	assert(
		value["entity-type"] == entitytype,
		statementInfo(statement) .. "'s value's entity-type is not " .. entitytype
	)
	return assert(
		value.id,
		statementInfo(statement) .. "'s value has no id field"
	)
end

-- -----------------------------------------------------------------------------
-- Return the item id for a statement that points to a data item
-- -----------------------------------------------------------------------------

local function getItemId(statement)
	return getAnyId(statement, "wikibase-item", "item")
end

-- -----------------------------------------------------------------------------
-- Return the property id for a statement that points to a property
-- -----------------------------------------------------------------------------

local function getPropertyId(statement)
	return getAnyId(statement, "wikibase-property", "property")
end

-- -----------------------------------------------------------------------------
-- Return a list of statements for a property, filter out obsolete ones
-- -----------------------------------------------------------------------------

local function getStatementList(entityId, propertyId)
	local result = {}
	for index, statement in ipairs(mw.wikibase.getBestStatements(entityId, propertyId)) do
		local useThis = true
		-- Filter out statements with start time in the future
		local startTime = statement.qualifiers and statement.qualifiers.P580
		if startTime then
			assert(#startTime == 1, statementInfo(statement) .. " has more than one start time")
			-- FIXME: Is there a better way to check whether a time value is in the future?
			local lang = mw.getContentLanguage()
			if startTime[1].datavalue and tonumber(lang:formatDate("U", "now")) < tonumber(lang:formatDate("U", startTime[1].datavalue.value.time)) then
				useThis = false
			end
		end
		-- Filter out statements with end time in the past
		local endTime = statement.qualifiers and statement.qualifiers.P582
		if endTime then
			assert(#endTime == 1, statementInfo(statement) .. " has more than one end time")
			-- FIXME: Is there a better way to check whether a time value is in the past?
			local lang =  mw.getContentLanguage()
			if endTime[1].datavalue and tonumber(lang:formatDate("U", "now")) > tonumber(lang:formatDate("U", endTime[1].datavalue.value.time)) then
				useThis = false
			end
		end
		if useThis then
			table.insert(result, statement)
		end
	end
	return result
end

-- -----------------------------------------------------------------------------
-- Return the rendered value of a single statement
-- -----------------------------------------------------------------------------

function p.getValueList(entityId, propertyId)
	local result = {}
	for index, statement in ipairs(getStatementList(entityId, propertyId)) do
		local value = mw.wikibase.renderSnak(statement.mainsnak)
		table.insert(result, value)
	end
	return result
end

-- -----------------------------------------------------------------------------
-- Return the item ids for statements that point to a data item
-- -----------------------------------------------------------------------------

function p.getItemIdList(entityId, propertyId)
	local result = {}
	for index, statement in ipairs(getStatementList(entityId, propertyId)) do
		local itemId = getItemId(statement)
		table.insert(result, itemId)
	end
	return result
end

-- -----------------------------------------------------------------------------
-- Return a single statement for a property, throw error if more than one
-- -----------------------------------------------------------------------------

local function getOneStatement(entityId, propertyId)
	local statements = getStatementList(entityId, propertyId)
	if #statements > 0 then
		assert(#statements == 1, entityId .. " has more than one statement for " .. propertyId)
		return statements[1]
	else
		return nil
	end
end

-- -----------------------------------------------------------------------------
-- Return the rendered value of a single statement
-- -----------------------------------------------------------------------------

function p.getOneValue(entityId, propertyId)
	local statement = getOneStatement(entityId, propertyId)
	if statement then
		return mw.wikibase.renderSnak(statement.mainsnak)
	else
		return nil
	end
end

-- -----------------------------------------------------------------------------
-- Return the property id for a single statement that point to a property
-- -----------------------------------------------------------------------------

function p.getOnePropertyId(entityId, propertyId)
	local statement = getOneStatement(entityId, propertyId)
	if statement then
		return getPropertyId(statement)
	else
		return nil
	end
end

-- -----------------------------------------------------------------------------
-- Return the item id for a single statement that point to a data item
-- -----------------------------------------------------------------------------

function p.getOneItemId(entityId, propertyId)
	local statement = getOneStatement(entityId, propertyId)
	if statement then
		return getItemId(statement)
	else
		return nil
	end
end

-- =============================================================================

return p