Module:Infobox chord

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Note: Do not invoke this module directly; use the corresponding template instead: Template:Infobox chord.

This module depends on the following other modules:

This module implements {{Infobox chord}} to generate an infobox providing information about a given chord.

local p = {}

local rat = require("Module:Rational")
local utils = require("Module:Utils")
local infobox = require("Module:Infobox")

function p.infobox_chord(frame)
	local debug_mode = frame.args["debug"]

	local page_name = frame:preprocess("{{PAGENAME}}")
	
	local debug_data = ""
	local infobox_data = {}
	local cats = ""
	local errors = ""

	local name = frame.args["Name"]
	if utils.value_provided(name) then
		local caption = "Name"
		if name:match(",") then
			caption = "Names"
			-- removing manual line breaks
			local matches
			name, matches = name:gsub("<br/?>", "")
			if matches > 0 then
				cats = cats .. "[[Category:Todo:remove manual line breaks]]"
			end
			-- removing whitespaces after commas
			name = name:gsub(",%s+", ",")
			-- placing line breaks after commas
			name = name:gsub(",", ",<br/>")
		end
		table.insert(infobox_data, {
			caption,
			name,
		})
	end

	if utils.value_provided(frame.args["Harmonics"]) then
		local harmonics = {}
		for hs in string.gmatch(frame.args["Harmonics"], "[^:]+") do
			h = tonumber(hs)  -- TODO: support rational entries?
			if h == nil or h < 1 then
				errors = errors .. "<p>error: invalid harmonic " .. hs .. "</p>"
			else
				table.insert(harmonics, h)
			end
		end
		local root = harmonics[1]
		if root == nil and errors == "" then
			errors = errors .. "<p>error: no harmonics found</p>"
		end
		if errors ~= "" then
			return errors
		end

		local prime_limit = 1
		local odd_limit = 1

		local ratio_string = {}
		for i, h in ipairs(harmonics) do
			for prime, n in pairs(utils.prime_factorization_raw(h)) do
				if prime > prime_limit then
					prime_limit = prime
				end
			end

			local gcd = utils._gcd(h, root)
			local numer = h / gcd
			local denom = root / gcd
			if i == 1 then
				ratio_string = ratio_string .. numer .. "⁄" .. denom
			else
				ratio_string = ratio_string .. " – " .. numer .. "⁄" .. denom 
			end
			local odd = numer
			while odd % 2 == 0 do
				odd = odd / 2
			end
			if odd > odd_limit then
				odd_limit = odd
			end
		end
		
		table.insert(infobox_data, {"Ratios", ratio_string})
		table.insert(infobox_data, {"[[Prime limit]]", prime_limit})
		table.insert(infobox_data, {"[[Odd limit]]", odd_limit})

		cats = cats .. "[[Category:" .. prime_limit .. "-limit chords]]"
		cats = cats .. "[[Category:" .. odd_limit .. "-odd-limit chords]]"
	end
	
	if debug_data ~= "" then
		table.insert(infobox_data, {
			"Debug",
			debug_data,
		})
	end

	local s = infobox.build("<u>Chord information</u>", infobox_data)
	if not debug_mode then
		s = s .. cats
	end
	return s
end

return p