Module:Is instance

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Usage

{{#invoke:Is instance|main|qid=|value=}}

This module will use Wikidata properties instance of (P31) and subclass of (P279) to determine whether or not an entity is an instance of some other entity.

Example

For example:

• HMS Ark Royal (Q847672)
  • is an instance of light aircraft carrier (Q1185562), which
    • is a subclass of aircraft carrier (Q17205), which
      • is a subclass of warship (Q3114762), which
        • is a subclass of naval vessel (Q177597), which
          • is a subclass of ship (Q11446).

To know that HMS Ark Royal (Q847672) is an instance of ship (Q11446), you can use:

{{#invoke:Is instance|main|qid=Q847672|value=Q11446}} = false

The output number indicates the minimum recursion depth to find the value required. An output of zero indicates that the item is not an instance.

Maximum depth

For performance considerations, the module will not go on searching indefinitely. The default maximum recursion depth is 5. If you want to change this, use the |maxdepth= parameter.

The above documentation is transcluded from Module:Is instance/doc. (edit | history)
Editors can experiment in this module's sandbox (edit | diff) and testcases (edit | run) pages.
Subpages of this module.

local p = {};

local function checksubclass(qid,value)
	local subclasses = mw.wikibase.getBestStatements( qid, "P279" )
	local currentdepth = 1
	local isInstance = false
	for i,statement in ipairs(subclasses) do
		if statement.mainsnak.datavalue.value.id == value then
			isInstance = true
			break
		end
	end
	return isInstance
end

local function checkitem(currentdepth)
	local instances
	if currentdepth == 0 then
		instances = mw.wikibase.getBestStatements(checklist[currentdepth][1],"P31")
	else
		instances = mw.wikibase.getBestStatements(checklist[currentdepth][1],"P279")
	end
	local isInstance = false
	checklist[currentdepth+1] = {}
	for i,statement in ipairs(instances) do
		local newitem = statement.mainsnak.datavalue.value.id
		if newitem == value then
			isInstance = true
			break
		end
		checklist[currentdepth+1][#checklist[currentdepth+1]+1]=newitem
	end
	if not isInstance then
		for i=1,#checklist[currentdepth+1],1 do
			if checksubclass(checklist[currentdepth+1][i],value) then
				isInstance = true
				break
			end
		end
	end
	return isInstance
end

function p.main(frame)
	local args = frame.args
	local pargs = frame:getParent().args
	maxdepth = 5
	local currentdepth = 0
	local qid = args.qid or pargs.qid
	checklist = {}
	checklist[currentdepth] = {qid}
	value = args.value or pargs.value
	return checkitem(currentdepth)
end

return p