Module:Hatnote group

Implements {{hatnote group}}, for merging multiple hatnotes into a grouped hatnote.

Technical details

The module attempts to find each hatnote-looking div element, and parse them into space-separated span elements wrapped in a larger, generic hatnote.

First, it matches every pattern that "looks like a hatnote" in its input text; this is where most problems are likely to originate as the pattern is fairly sensitive to any difference in the form of a hatnote.

From each of the pattern matches, it constructs a table. Each element ("row") of the table corresponds to one original hatnote, and is a table that contains a string with the rendered inner content of the hatnote, and an inner table containing any "extra" classes associated with that hatnote (e.g. selfreference from a {{self reference}} hatnote, or any classes from the extraclasses parameter of {{hatnote}}).

It also separately looks for all categories in case they're present outside the hatnote div element, and adds them to a concatenated string of all "loose categories" to make sure they're not accidentally removed by the hatnote grouping process.

Once all rows are available, it looks at the tables of classes. It adds every class from every row into a table of "universal" classes, then filters out the ones that aren't universal by looking at each row's list and eliminating an item if it isn't present in any one row. Then, "universal" classes are removed from each row's classes table, so that they're not duplicated later.

This processing having been done, each row is formatted with a span element that includes the extra classes associated with that row, the spans for each row are joined as a space-separated list, the "loose categories" are tacked on in turn, and then the resulting string is fed into the main hatnote module, with extra classes on the main hatnote being supplied by collating the "universal classes" table into a space-separated list of its keys.

---

local mHatnote = require('Module:Hatnote')
local p = {}

--Collates key-based table of classes into usable class list
function collateClassList (listTable)
	local list = {}
	for k, v in pairs(listTable) do
		if v and type(k) == "string" then table.insert(list, k) end
	end
	return table.concat(list, " ")
end

--Passes through single argument from parent frame
function p.group (frame)
	return p._group(frame:getParent().args[1], frame:getParent().args.category)	
end

function p._group (inputText, category)
	--If there's an error element, pass everything through unchanged for easier
	--error resolution
	if string.find(inputText, '<%a- class="error"', 1, true) then return inputText end
	
	--Heavily reused hatnote data capture pattern
	local hatnotePattern = '(<div role="note" class="hatnote navigation%-not%-searchable%s?(.-)">(.-)</div>)'
	
	--Capture hatnote divs and "loose" categories; we'll ignore everything else
	local rawDivs = {}
	local looseCategories = ''
	for x in string.gmatch(inputText, hatnotePattern) do
		table.insert(rawDivs, x)
	end
	for x in string.gmatch(inputText, '%[%[Category:.-%]%]') do
		looseCategories = looseCategories .. x
	end

	--if no inner hatnotes, return an error
	if not rawDivs[1] then
		return mHatnote.makeWikitextError(
			'no inner hatnotes detected',
			'Template:Hatnote group',
			category
		)
	end

	--Preprocess divs into strings and classes
	local innerHatnotes = {}
	for k, v in pairs(rawDivs) do
		row = {}
		row.text = string.gsub(v, hatnotePattern, '%3')
		--Here we set class names as keys for easier intersection later
		row.classes = {}
		for m, w in ipairs(
			mw.text.split(
				string.gsub(v, hatnotePattern, '%2'),
				' ',
				true
			)
		) do
			row.classes[mw.text.trim(w)] = true
		end
			
		table.insert(innerHatnotes, row)
	end
	
	--Identify any universal classes ("hatnote" ignored by omission earlier)
	local universalClasses = {}
	--clone first classes table to force passing by value rather than reference
	for k, v in pairs(innerHatnotes[1].classes) do universalClasses[k] = v end
	for k, v in ipairs(innerHatnotes) do
		for m, w in pairs(universalClasses) do
			universalClasses[m] = (universalClasses[m] and v.classes[m])
		end
	end
	
	--Remove universal classes from div items, then create class strings per row
	for k, v in ipairs(innerHatnotes) do
		for m, w in pairs(v.classes) do
			if universalClasses[m] then v.classes[m] = nil end
		end
		v.classString = collateClassList(v.classes)
	end
	
	--Process div items into classed span items
	local innerSpans = {}
	for k, v in ipairs(innerHatnotes) do
		table.insert(
			innerSpans,
			(v.classString ~= '') and
				string.format('<span class="%s">%s</span>', v.classString, v.text) or
				string.format('<span>%s</span>', v.text)
		)
	end

	--Concatenate spans and categories, and return wrapped as a single hatnote
	local outputText = table.concat(innerSpans, " ") .. looseCategories
	local hnOptions = {extraclasses = collateClassList(universalClasses)}
	return mHatnote._hatnote(outputText, hnOptions)
end

return p