Module:Make Wikisource link

local p = {}
local getArgs = require('Module:Arguments').getArgs
local yesno = require('Module:Yesno')

function p.makeLink(frame)
	local args = getArgs(frame)
	local lang = args['explicit_lang_param'] or args['implicit_lang_param'] or 'en'
	local page = mw.title.getCurrentTitle()
	local pagename = page.text
	local authorPrefix = args.works and frame:expandTemplate{ title = 'Wikisource/Author', args = { lang } } or ''
	local linkTarget
	local displayText
	local toReturn
	
	-- get the Wikidata sitelink
	local wikidataSitelink = mw.wikibase.getSitelink(
		mw.wikibase.getEntityIdForCurrentPage() or '',
		lang .. 'wikisource'
	)
		
	-- if we have a language parameter, we look at the second unnamed parameter for the source title
	local checkIndexForTarget = args['implicit_lang_param'] and 2 or 1
	-- and then use the next index for display
	local checkIndexForDisplay = checkIndexForTarget + 1
	
	--[[---------
	Set the link target
	--]]---------
	if args['wslink'] then
		linkTarget = args['wslink']
	elseif args[checkIndexForTarget] then
		-- we have a source title parameter, so return that
		linkTarget = args[checkIndexForTarget]
	elseif wikidataSitelink then
		-- use Wikidata
		linkTarget = wikidataSitelink
	else
		-- if Wikidata returns nothing, search for the {{PAGENAME}}
		linkTarget = 'Special:Search/' .. pagename
		-- we have no parameters and nothing at Wikidata, so we are flying blind
		-- We set displayText now to avoid including the Special:Search in the display text
		displayText = pagename
	end
	
	-- clear the Author: prefix for now; will add it back later if needed
	-- this prevents duplicate prefixes (Author:Author:Shakespeare)
	-- and avoids displayText with any author prefix
	linkTarget = string.gsub(linkTarget, '^' .. authorPrefix, '')
	
	--[[---------	
	Now build the displayText
	--]]---------
	
	if not displayText then
		-- we did not set displayText in the above steps, so set it now
		-- first we check for an explicit display text, or else we set it to be the link target
		displayText = args['title'] or args[checkIndexForDisplay] or linkTarget
	end
	
	--[[---------	
	Now we check whether we should categorize in Category:Wikisource templates with missing id
	--]]---------
	
	-- initialize errorCategory as true
	local errorCategory = true
	
	if wikidataSitelink then
		-- we do have a sitelink at Wikidata
		errorCategory = false
	elseif yesno(args.nocat, true) then
		-- we have a |nocat parameter
		errorCategory = false
	elseif page.namespace ~= 0 then
		-- only care about mainspace
		errorCategory = false
	elseif string.match(pagename, '^List') then
		-- we are on a list page, and those should not have Wikisource links
		errorCategory = false
	else
		-- Check whether this is a disambiguation page or set index article
		-- we do this check last to avoid using [[WP:EXPENSIVE]] parser calls if possible
		for _, cat in ipairs(page.categories) do
			if cat == 'All disambiguation pages' or cat == 'All set index articles' then
				errorCategory = false
				break
			end
		end
	end
	
	-- build the link
	toReturn = '[[:s:' .. lang .. ':' .. authorPrefix .. linkTarget .. '|' .. displayText .. ']]'
	
	-- append the error category if needed
	if errorCategory then
		toReturn = toReturn .. '[[Category:Wikisource templates with missing id|' .. pagename .. ']]' 
	end

	return toReturn
end

return p
Usage
