Module:Is instance/sandbox

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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}} = 3

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.
Add categories to the /doc subpage. Subpages of this module.

local p = {};

function p._main(args)
	--local pargs = frame:getParent().args
	value = args.value
	local qid = args.qid or ""
	if qid == '' then
		qid = mw.wikibase.getEntityIdForCurrentPage()
	end
	if not qid then
		return 0
	end
	local checklist,depth,maxdepth,isInstance = {{qid}},0,nil,false
	if args.maxdepth then
		maxdepth = tonumber(args.maxdepth)
	else
		maxdepth = 5
	end
	local function checklayer(depth) -- check subclasses of items at current depth
		checklist[depth+1] = {} -- setup next layer of table
		local j = 0
		for j = 1,#checklist[depth] do -- loop over items at current depth
			local property
			if depth == 1 then
				property = "P31" -- use P31 for depth 1
			else
				property = "P279" -- use P279 for depths 2+
			end
			local subclasses = mw.wikibase.getBestStatements(checklist[depth][j],property) -- get P31 or P279 statements
			for i,statement in ipairs(subclasses) do -- loop through items at next depth
				if statement.mainsnak.snaktype == 'value' then
					local newitem = statement.mainsnak.datavalue.value.id
					if newitem == value then
						isInstance = true
					else
						checklist[depth+1][#checklist[depth+1]+1] = newitem -- add item to next depth of checklist table
					end
				end
			end
		end
		return isInstance
	end
	while not isInstance and depth<maxdepth do
		depth = depth+1
		checklayer(depth)
	end
	if not isInstance then
		depth = 0 -- indicates not isInstance
	end
	return depth -- return depth that item was found
end

function p.main(frame)
	return p._main(frame.args)	
end

return p