Module:Separated entries

Documentation

-- This module was copied from https://en.wikipedia.org/wiki/Module:Separated_entries
-- and isPositiveInteger, numKeys & compressSparseArray from https://en.wikipedia.org/wiki/Module:TableTools.
-- Thanks Wikipedia :)

-- This module takes positional parameters as input and concatenates them with
-- an optional separator. The final separator (the "conjunction") can be
-- specified independently, enabling natural-language lists like
-- "foo, bar, baz and qux". The starting parameter can also be specified.


------------------------------------------------------------------------------------
-- isPositiveInteger
--
-- This function returns true if the given value is a positive integer, and false
-- if not. Although it doesn't operate on tables, it is included here as it is
-- useful for determining whether a given table key is in the array part or the
-- hash part of a table.
------------------------------------------------------------------------------------
function isPositiveInteger(v)
	return type(v) == 'number' and v >= 1 and math.floor(v) == v and v < math.huge
end

------------------------------------------------------------------------------------
-- numKeys
--
-- This takes a table and returns an array containing the numbers of any numerical
-- keys that have non-nil values, sorted in numerical order.
------------------------------------------------------------------------------------
function numKeys(t)
	local isPositiveInteger = isPositiveInteger
	local nums = {}
	for k in pairs(t) do
		if isPositiveInteger(k) then
			nums[#nums + 1] = k
		end
	end
	table.sort(nums)
	return nums
end


------------------------------------------------------------------------------------
-- compressSparseArray
--
-- This takes an array with one or more nil values, and removes the nil values
-- while preserving the order, so that the array can be safely traversed with
-- ipairs.
------------------------------------------------------------------------------------
function compressSparseArray(t)
	local ret = {}
	local nums = numKeys(t)
	for _, num in ipairs(nums) do
		ret[#ret + 1] = t[num]
	end
	return ret
end

local p = {}

function p._main(args)
	local separator = args.separator
		-- Decode (convert to Unicode) HTML escape sequences, such as "&#32;" for space.
		and mw.text.decode(args.separator) or ''
	local conjunction = args.conjunction and mw.text.decode(args.conjunction) or separator
	-- Discard values before the starting parameter.
	local start = tonumber(args.start)
	if start then
		for i = 1, start - 1 do args[i] = nil end
	end
	-- Discard named parameters.
	local values = compressSparseArray(args)
	return mw.text.listToText(values, separator, conjunction)
end

local function makeInvokeFunction(separator, conjunction, first)
	return function (frame)
		local args = require('Module:Arguments').getArgs(frame)
		args.separator = separator or args.separator
		args.conjunction = conjunction or args.conjunction
		args.first = first or args.first
		return p._main(args)
	end
end

p.main = makeInvokeFunction()
p.br = makeInvokeFunction('<br />')
p.comma = makeInvokeFunction(mw.message.new('comma-separator'):plain())

return p