Module:grc-headword

local export = {}

local m_params = require("Module:parameters")
local m_grc_utils = require("Module:grc-utilities")
local m_str_utils = require("Module:string utilities")

local tokenize = m_grc_utils.tokenize
local find_ambig = m_grc_utils.findAmbig

local diacritic = mw.loadData("Module:grc-utilities/data").diacritic

local full_headword = require("Module:headword").full_headword
local get_accent_term = require("Module:grc-accent").get_accent_term
local serial_comma_join = require("Module:table").serialCommaJoin

local lang = require("Module:languages").getByCode("grc")
local canonical_name = lang:getCanonicalName()

local NAMESPACE = mw.title.getCurrentTitle().nsText
local PAGENAME = mw.loadData("Module:headword/data").pagename
local MAINSPACE = NAMESPACE == ""

local reconstructed_prefix = NAMESPACE == "Reconstruction" and "reconstructed " or ""

local toNFD = mw.ustring.toNFD
local ufind = m_str_utils.find
local umatch = m_str_utils.match

local pos_functions = {}

local legal_declension = {
	["first"] = true,
	["second"] = true,
	["Attic"] = true,
	["third"] = true,
	["irregular"] = true,
}

-- Also used to validate genders.
local gender_names = {
	["m"]	= "masculine",
	["m-s"] = "masculine",
	["m-d"] = "masculine",
	["m-p"] = "masculine",
	["f"]	= "feminine",
	["f-s"] = "feminine",
	["f-d"] = "feminine",
	["f-p"] = "feminine",
	["n"]	= "neuter",
	["n-s"] = "neuter",
	["n-d"] = "neuter",
	["n-p"] = "neuter",
	["?"]	= "unknown gender",
	["?-s"] = "unknown gender",
	["?-d"] = "unknown gender",
	["?-p"] = "unknown gender",
}

local function quote(text)
	return "“" .. text .. "”"
end

local function format(array, concatenater)
	if not array[1] then
		return ""
	else
		return "; ''" .. table.concat(array, concatenater) .. "''"
	end
end
	
-- Process arg the way [[Module:parameters]] would.
local function process_arg(val)
	if val == "" then
		val = nil
	end
	if val then
		val = mw.text.trim(val)
	end
	return val
end

-- Returns true if text contains one character from the Greek and Coptic or
-- Greek Extended blocks.
local function contains_Greek(text)
	-- Matches any character in Greek and Coptic block except the first line:
	-- ͰͱͲͳʹ͵Ͷͷͺͻͼͽ;Ϳ
	local basic_Greek = "[\206-\207][\128-\191]"
	-- Exactly matches entire Greek Extended block.
	local Greek_extended = "\225[\188-\191][\128-\191]"
	return (string.find(text, basic_Greek) or string.find(text, Greek_extended)) and true or false
end

-- A cheaper version of makeEntryName. Doesn't remove underties, which should
-- not appear in headwords, or convert curly apostrophes, spacing smooth
-- breathings, and spacing coronides to straight apostrophes.
local function remove_macron_breve(text)
	return toNFD(text):gsub("\204[\132\134]", "")
end

local function remove_links(text)
	if text:find("%[%[") then
		return (text
			:gsub("%[%[[^|]+|([^%]]+)%]%]", "%1")
			:gsub("%[%[([^%]]+)%]%]", "%1"))
	else
		return text
	end
end

local U = m_str_utils.char
local macron = U(0x304)
local breve = U(0x306)
local rough = U(0x314)
local smooth = U(0x313)
local diaeresis = U(0x308)
local acute = U(0x301)
local grave = U(0x300)
local circumflex = U(0x342)
local subscript = U(0x345)
local diacritic_patt = table.concat{
	"[",
	macron, breve,
	rough, smooth, diaeresis,
	acute, grave, circumflex,
	subscript,
	"]"
}
local accent_patt = "[" .. acute .. grave .. circumflex .. "]"

-- Controls whether or not the headword can be provided in the first numbered parameter.
local function needs_headword(text)
	local lengthDiacritic = "[" .. macron .. breve .. circumflex .. subscript .. "]"
	local aiu_diacritic = "^([ΑαΙιΥυ])(" .. diacritic_patt .. "*)$"
	
	text = remove_links(text)
	
	-- If page name has straight apostrophe, a headword with curly apostrophe should be provided.
	if text:find("'") then
		return true
	end
	
	-- breaks the word into units
	for _, token in ipairs(tokenize(text)) do
		local vowel, diacritics = umatch(token, aiu_diacritic)
			
		if vowel and (diacritics == "" or
				not ufind(diacritics, lengthDiacritic)) then
			return true
		end
	end
		
	return false
end

-- Process numbered parameters before using [[Module:parameters]], as
-- [[Module:parameters]] converts several named parameters into arrays, which
-- makes them more difficult to manipulate.

local function process_numbered_params(args, Greek_params, nonGreek_params)
	if not nonGreek_params then
		nonGreek_params = { false }
	end
	
	local max_Greek_param_index = #Greek_params
	
	-- Clone args table so that its values can be modified.
	args = require("Module:table").shallowcopy(args)
	
	if args.head then
		-- [[Special:WhatLinksHere/Wiktionary:Tracking/grc-headword/head param]]
		require("Module:debug").track("grc-headword/head param")
	end
	
	local last_Greek_param_index = 0
	for i, arg in ipairs(args) do
		if arg == "-" or contains_Greek(arg) then
			last_Greek_param_index = i
		else
			break
		end
	end
	
	local head_in_arg1 = false
	
	if last_Greek_param_index == max_Greek_param_index then
		if not MAINSPACE or needs_headword(PAGENAME) then
			head_in_arg1 = true
		else
			error(("The pagename does not have ambiguous vowels, so there cannot be "
					.. max_Greek_param_index
					.. " numbered parameter%s. See template documentation for more details.")
					:format(max_Greek_param_index == 1 and "" or "s"))
		end
	
	elseif last_Greek_param_index > max_Greek_param_index then
		error("Too many numbered parameters containing Greek text or hyphens. There can be at most "
				.. max_Greek_param_index .. ".")
	
	-- For indeclinable nouns: {{grc-noun|Ἰσρᾱήλ|m}}
	-- First parameter is headword if equal to pagename when macrons and breves are removed.
	elseif args[1] and remove_macron_breve(args[1]):gsub("’", "'") == toNFD(PAGENAME) then
		if args.head then
			error("Parameter 1 appears to be the headword, so the head parameter " .. quote(args.head) .. " is not needed.")
		end
		args.head, args[1] = args[1], nil
	
	else
		table.remove(Greek_params, 1) -- Remove "head" parameter.
	end
	
	local function process_params(start_i, end_i, param_names)
		local i = 1 -- Index in the table of parameter names.
		for numbered = start_i, end_i do
			local named = param_names[i]
			i = i + 1
			
			if named then
				-- Process parameters, as they have not been processed by [[Module:parameters]].
				args[numbered], args[named] =
					process_arg(args[numbered]), process_arg(args[named])
			
			-- This should not happen, because the number of Greek parameters
			-- has already been checked.
			elseif args[numbered] then
				error("No purpose for parameter " .. numbered .. ".")
			end
				
			if args[numbered] then
				if named then
					-- This fixes an error caused by the kludgy way in which the
					-- numbered parameters of {{grc-preposition}} are handled.
					if numbered ~= named then
						if args[named] then
							error("Parameter " .. numbered .. " is not needed when parameter " .. named .. " is present.")
						end
						
						args[named], args[numbered] = args[numbered], nil
					end
				else
					error("Parameter " .. numbered .. ", " .. args[numbered] .. ", has no purpose.")
				end
			end
		end
	end
	
	process_params(1, last_Greek_param_index, Greek_params)
	process_params(last_Greek_param_index + 1, #Greek_params + #nonGreek_params, nonGreek_params)
	
	if args.head == "-" then
		error("The headword cannot be absent.")
	end
	
	return args
end

local function process_heads(data, poscat)
	data.no_redundant_head_cat = #data.heads == 0
	if #data.heads == 0 then
		table.insert(data.heads, PAGENAME)
	end
	
	local suffix = data.heads[1]:find("^%*?%-") and true or false
	for _, head in ipairs(data.heads) do
		if suffix and head:sub(1, 1) ~= "-" then
			error("The first headword has a hyphen, so headword #" .. i ..
					", " .. quote(head) .. ", should as well.")
		end
		local accent = get_accent_term(head)
		if accent then
			table.insert(data.categories,
				("%s %s terms"):format(canonical_name, accent))
		elseif not ufind(toNFD(head), accent_patt) then
			table.insert(data.categories,
				("%s unaccented terms"):format(canonical_name))
		else
			table.insert(data.categories,
				("%s terms with irregular accent"):format(canonical_name))
		end
		
		if MAINSPACE then
			local _, vowel_set = find_ambig(head, false)
			for vowel in pairs(vowel_set) do
				require("Module:debug").track {
					"grc-headword/ambig",
					"grc-headword/ambig/" .. vowel
				}
			end
			if not head:find(" ") and toNFD(head):find(grave) then
				error("Head #" .. i .. ", " .. quote(head) ..
					", contained a grave accent, but no space. Grave accent can only be used in multi-word terms.")
			end
		end
	end
	
	if suffix then
		data.pos_category = "suffixes"
		if not poscat:find "forms$" then
			table.insert(data.categories, canonical_name .. " " .. poscat .. "-forming suffixes")
		end
	end
end

local function unlinked_form(label)
	return { label = label, { nolink = true, term = "—" } }
end

local function add_gender_form(inflections, gender_arg, gender_name, allow_blank_forms)
	if gender_arg[1] then
		if allow_blank_forms and not gender_arg[2] and gender_arg[1] == "-" then
			table.insert(inflections, unlinked_form(gender_name))
		else
			gender_arg.label = gender_name
			table.insert(inflections, gender_arg)
		end
	end
end

local function adj_and_part_forms(total_forms, args, inflections, allow_blank_forms)
	if total_forms == 2 then
		add_gender_form(inflections, args.f, "feminine", allow_blank_forms)
	end
	
	add_gender_form(inflections, args.n, "neuter", allow_blank_forms)
end

local function handle_degree_of_comparison(args, data, is_declined_form)
	if args.deg ~= nil then
		if args.deg == 'comp' then
			data.pos_category = reconstructed_prefix .. "comparative adjectives"
		elseif args.deg == 'super' then
			data.pos_category = reconstructed_prefix .. "superlative adjectives"
		else
			error('Adjective degree ' .. quote(args.deg) .. ' not recognized.')
		end
		
		if is_declined_form then
			data.pos_category = data.pos_category:gsub("adjectives", "adjective forms")
		end
	end
end

function export.show(frame)
	local args = frame:getParent().args
	
	local poscat = frame.args[1] or error("Part of speech has not been specified. Please pass parameter 1 to the module invocation.")
	local subclass = frame.args[2]
	
	local data = {
		lang = lang,
		pos_category = reconstructed_prefix .. poscat,
		categories = {}, heads = {}, genders = {}, inflections = {}
	}
	local appendix = {}
	
	if pos_functions[poscat] then
		pos_functions[poscat](args, data, appendix, poscat, subclass)
	end
	
	return full_headword(data) .. format(appendix, ", ")
end

function export.test(frame_args, parent_args, pagename)
	PAGENAME = pagename
	local poscat = frame_args[1] or error("Part of speech has not been specified. Please pass parameter 1 to the module invocation.")
	local subclass = frame_args[2]
	
	local data = {
		pos_category = reconstructed_prefix .. poscat,
		categories = {}, heads = {}, genders = {}, inflections = {}
	}
	local appendix = {}
	
	if pos_functions[poscat] then
		pos_functions[poscat](parent_args, data, appendix, poscat, subclass)
	end
	
	return data
end

pos_functions["nouns"] = function(args, data, appendix, poscat)
	args = process_numbered_params(args, { "head", "gen" }, { "g", "decl" })
	
	local params = {
		-- Numbered parameters 1, 2, 3, 4 handled above.
		head = { list = true },
		gen = { list = true },
		g = { list = true, default = '?' },
		dim = { list = true },
		decl = { list = true },
		sort = {}, -- for [[Unsupported titles/Ancient Greek dish]]; please do not use otherwise
	}
	args = m_params.process(args, params, nil, "grc-headword", "nouns")
	
	data.heads = args.head
	process_heads(data, "noun")
	
	for _, g in ipairs(args.g) do
		local gender_name = gender_names[g]
		if gender_name then
			table.insert(data.genders, g)
			table.insert(data.categories,
				("%s %s %s"):format(canonical_name, gender_name, poscat))
		else
			error("Gender " .. quote(g) .. " is not an valid " .. canonical_name .. " gender.")
		end
	end
	
	if not args.gen[1] then
		table.insert(data.inflections, { label = "[[Appendix:Glossary#indeclinable|indeclinable]]" })
		table.insert(data.categories,
			("%s indeclinable %s")
				:format(canonical_name, poscat))
		for _, g in ipairs(args.g) do
			table.insert(data.categories,
				("%s %s indeclinable %s")
					:format(canonical_name, gender_names[g], poscat))
		end
		if args.decl[1] then
			error("Declension class " .. quote(args.decl[1])
					.. " has been given, but no genitive form has been given, so the word cannot belong to a declension class.")
		end
	else
		if not args.gen[2] and args.gen[1] == "-" then
			table.insert(data.inflections, unlinked_form("genitive"))
		else
			args.gen.label = "genitive"
			table.insert(data.inflections, args.gen)
		end
		
		if args.decl[2] then
			table.insert(data.inflections, { label = 'variously declined' })
			table.insert(data.categories,
				("%s %s with multiple declensions")
					:format(canonical_name, poscat))
		elseif not args.decl[1] then
			table.insert(appendix, "? declension")
		end
		
		for _, decl_class in ipairs(args.decl) do
			if legal_declension[decl_class] then
				local not_irregular = decl_class ~= "irregular"
				if not_irregular then
					table.insert(appendix,
						("[[Appendix:%s %s declension|%s declension]]")
							:format(canonical_name, decl_class, decl_class))
					table.insert(data.categories,
						("%s %s-declension %s")
							:format(canonical_name, decl_class, poscat))
				else
					table.insert(appendix,
						("%s declension"):format(decl_class))
					table.insert(data.categories,
						("%s irregular %s"):format(canonical_name, poscat))
				end
				
				if not_irregular then
					for _, g in ipairs(args.g) do
						table.insert(data.categories,
							("%s %s %s in the %s declension")
								:format(canonical_name, gender_names[g], poscat, decl_class))
					end
				end
			else
				error("Declension " .. quote(decl_class) .. " is not a legal " ..
					canonical_name .. " declension. Choose “first”, “second”, “third”, or “irregular”.")
			end
		end
	end
	
	-- Check first-declension endings and gender.
	if args.decl[1] == "first" then
		local alpha = "α[" .. macron .. breve .. "]?[" .. acute .. circumflex .. "]?"
		local eta = "η[" .. acute .. circumflex .. "]?"
		
		local gender = args.g[1]
		local alpha_ending, eta_ending
		if gender == "f" then
			alpha_ending = alpha .. "$"
			eta_ending = eta .. "$"
		elseif gender == "m" then
			alpha_ending = alpha .. "ς$"
			eta_ending = eta .. "ς$"
		else
			gender = nil
			require("Module:debug").track("grc-noun/1st/incorrect or no gender")
		end
		
		if gender then
			for _, head in ipairs(data.heads) do
				head = toNFD(remove_links(head))
				if not (ufind(head, eta_ending) or ufind(head, alpha_ending)) then
					require("Module:debug").track("grc-noun/1st/" .. gender .. " with incorrect ending")
				end
			end
		end
	end
	
	if args.dim[1] then
		args.dim.label = "diminutive"
		table.insert(data.inflections, args.dim)
	end
end

pos_functions["proper nouns"] = pos_functions["nouns"]

pos_functions["verbs"] = function(args, data)
	args = process_numbered_params(args, { "head" })

	local params = {
		head = { list = true }
	}
	local args = m_params.process(args, params, nil, "grc-headword", "verbs")
	data.heads = args.head
	
	process_heads(data, "verb")
end

pos_functions["adverbs"] = function(args, data)
	args = process_numbered_params(args, { "head", "comp", "super" }, { "type" })
	
	local params = {
		head = { list = true },
		comp = { list = true },
		super = { list = true },
		type = { list = true },
	}
	local args = m_params.process(args, params, nil, "grc-headword", "adverbs")
	data.heads = args.head
	
	process_heads(data, "adverb")
	
	-- Show comparative and superlative. If comparative or superlative is absent
	-- while the other form is present, show "no comparative" or "no superlative".
	if args.comp[1] then
		args.comp.label = 'comparative'
		table.insert(data.inflections, args.comp)
	elseif args.super[1] then
		table.insert(data.inflections, { label = 'no comparative' })
	end
	if args.super[1] then
		args.super.label = 'superlative'
		table.insert(data.inflections, args.super)
	elseif args.comp[1] then
		table.insert(data.inflections, { label = 'no superlative' })
	end
	
	if args.type[1] then
		local adverb_types = require "Module:table".listToSet {
			"demonstrative", "indefinite", "interrogative", "relative",
		}
		
		for _, type in ipairs(args.type) do
			if adverb_types[type] then
				table.insert(data.categories, canonical_name .. " " .. type .. " adverbs")
			else
				error(quote(type) .. " is not a valid subcategory of adverb.")
			end
		end
	end
end

pos_functions["numerals"] = function(args, data)
	args = process_numbered_params(args, { "head", "f", "n" })
	
	local params = {
		head = { list = true },
		f = { list = true },
		n = { list = true },
		car = { list = true },
		ord = { list = true },
		adv = { list = true },
		coll = { list = true },
	}
	local args = m_params.process(args, params, nil, "grc-headword", "numerals")
	data.heads = args.head
	
	process_heads(data, "numeral")
	
	adj_and_part_forms(2, args, data.inflections, false)
	
	local num_type_names = {
		car = "cardinal", ord = "ordinal", adv = "adverbial", coll = "collective",
	}
	
	for _, num_type in ipairs { "car", "ord", "adv", "coll" } do
		if args[num_type][1] then
			args[num_type].label = num_type_names[num_type]
			table.insert(data.inflections, args[num_type])
		end
	end
end



pos_functions["participles"] = function(args, data, appendix, _, subclass)
	if subclass == "1&2" or subclass == "1&3" then
		pos_functions["part-" .. subclass](args, data, appendix)
	else
		error('Participle subclass ' .. quote(subclass) .. ' not recognized.')
	end
end

pos_functions["part-1&2"] = function(args, data, appendix)
	args = process_numbered_params(args, { "head", "f", "n" })
	
	local params = {
		-- Parameters 1, 2, and 3 handled above.
		head = { list = true },
		f = { list = true, required = true },
		n = { list = true, required = true },
	}
	local args = m_params.process(args, params, nil, "grc-headword", "part-1&2")
	data.heads = args.head
	
	process_heads(data, "participle")
	
	table.insert(data.genders, "m")
	
	table.insert(appendix, "[[Appendix:" .. canonical_name ..
			" first declension|first]]/[[Appendix:" .. canonical_name ..
			" second declension|second declension]]")
	
	adj_and_part_forms(2, args, data.inflections, false)
end

pos_functions["part-1&3"] = function(args, data, appendix)
	args = process_numbered_params(args, { "head", "f", "n" })
	
	local params = {
		-- Parameters 1, 2, and 3 handled above.
		head = { list = true },
		f = { list = true, required = true },
		n = { list = true, required = true },
	}
	local args = m_params.process(args, params, nil, "grc-headword", "part-1&3")
	data.heads = args.head
	
	process_heads(data, "participle")
	
	table.insert(data.genders, "m")
	
	table.insert(appendix, "[[Appendix:" .. canonical_name ..
			" first declension|first]]/[[Appendix:" .. canonical_name ..
			" third declension|third declension]]")
	
	adj_and_part_forms(2, args, data.inflections, false)
end

pos_functions["adjectives"] = function(args, data, appendix, _, subclass)
	local subclasses = {
		["1&2"] = true, ["1&3"] = true, ["2nd"] = true, ["3rd"] = true
	}
	
	if subclasses[subclass] then
		pos_functions["adj-" .. subclass](args, data, appendix)
	else
		error('Adjective subclass ' .. quote(subclass) .. ' not recognized.')
	end
end

pos_functions["adj-1&2"] = function(args, data, appendix)
	args = process_numbered_params(args, { "head", "f", "n" })
	
	local params = {
		-- Parameters 1, 2, and 3 handled above.
		head = { list = true },
		f = { list = true, required = true },
		n = { list = true, required = true },
		deg = {},
	}
	local args = m_params.process(args, params, nil, "grc-headword", "adj-1&2")
	data.heads = args.head
	
	process_heads(data, "adjective")
	
	table.insert(data.genders, "m")
	
	table.insert(appendix, "[[Appendix:" .. canonical_name ..
			" first declension|first]]/[[Appendix:" .. canonical_name ..
			" second declension|second declension]]")
	
	handle_degree_of_comparison(args, data, false)
	
	adj_and_part_forms(2, args, data.inflections, true)
end

pos_functions["adj-1&3"] = function(args, data, appendix)
	args = process_numbered_params(args, { "head", "f", "n" })
	
	local params = {
		-- Parameters 1, 2, and 3 handled above.
		head = { list = true },
		f = { list = true, required = true },
		n = { list = true, required = true },
	}
	local args = m_params.process(args, params, nil, "grc-headword", "adj-1&3")
	data.heads = args.head
	
	process_heads(data, "adjective")
	
	table.insert(data.genders, "m")
	
	table.insert(appendix, "[[Appendix:" .. canonical_name ..
		" first declension|first]]/[[Appendix:" .. canonical_name ..
		" third declension|third declension]]")
	
	adj_and_part_forms(2, args, data.inflections, true)
end

pos_functions["adj-2nd"] = function(args, data, appendix)
	args = process_numbered_params(args, { "head", "n" })
	
	local params = {
		-- Parameters 1 and 2 handled above.
		head = { list = true },
		n = { list = true, required = true },
	}
	local args = m_params.process(args, params, nil, "grc-headword", "adj-2nd")
	data.heads = args.head
	
	process_heads(data, "adjective")
	
	table.insert(data.genders, "m")
	table.insert(data.genders, "f")
	
	table.insert(appendix, "[[Appendix:" .. canonical_name .. " second declension|second declension]]")
	
	adj_and_part_forms(1, args, data.inflections, true)
end

pos_functions["adj-3rd"] = function(args, data, appendix)
	args = process_numbered_params(args, { "head", "n" })
	
	local params = {
		-- Parameters 1 and 2 handled above.
		head = { list = true },
		n = { list = true, required = true },
		deg = {},
	}
	local args = m_params.process(args, params, nil, "grc-headword", "adj-3rd")
	data.heads = args.head
	
	process_heads(data, "adjective")
	
	table.insert(data.genders, "m")
	table.insert(data.genders, "f")
	
	table.insert(appendix, "[[Appendix:" .. canonical_name .. " third declension|third declension]]")
	
	handle_degree_of_comparison(args, data, false)
	
	adj_and_part_forms(1, args, data.inflections, true)
end

local case_abbreviations = {
	nom = 'nominative',
	gen = 'genitive',
	dat = 'dative',
	acc = 'accusative',
	voc = 'vocative',
}

pos_functions["prepositions"] = function(args, data, appendix)
	-- This allows up to 4 numbered parameters, which is the number of cases
	-- that can appear after prepositions.
	args = process_numbered_params(args, { "head" }, { 1, 2, 3 })
	
	local params = {
		[1] = { list = true },
		head = { list = true },
	}
	local args = m_params.process(args, params, nil, "grc-headword", "prepositions")
	data.heads = args.head
	
	process_heads(data, "preposition")
	
	if args[1][1] then
		local cases = {}
		for _, case in ipairs(args[1]) do
			if case_abbreviations[case] then
				table.insert(data.categories, canonical_name .. " " .. case_abbreviations[case] .. " prepositions")
				table.insert(cases, "[[Appendix:Glossary#" .. case_abbreviations[case] .. "|" .. case_abbreviations[case] .. "]]")
			else
				error('Case abbreviation ' .. quote(case) ..
					' not recognized. Please choose from ' ..
					mw.text.listToText(require("Module:fun").map(
							quote,
							{ "gen", "dat", "acc" }
					)) .. '.'
				)
			end
		end
		table.insert(data.inflections, { label = 'governs the ' .. serial_comma_join(cases) })
	end
end

pos_functions["particles"] = function(args, data)
	args = process_numbered_params(args, { "head" })
	
	local params = {
		head = { list = true },
		disc = { type = 'boolean' },
		mod = { type = 'boolean' },
		inter = { type = 'boolean' },
		neg = { type = 'boolean' },
	}
	local args = m_params.process(args, params, nil, "grc-headword", "particles")
	data.heads = args.head
	
	process_heads(data, "particles")
	
	for _, item in ipairs{ { "disc", "discourse" }, { "mod", "modal" }, { "inter", "interrogative" }, { "neg", "negative" } } do
		if args[item[1]] then
			local descriptor = item[2]
			table.insert(data.categories, canonical_name .. " " .. descriptor .. " particles")
			table.insert(data.inflections, { label = descriptor .. ' particle' })
		end
	end
end

local valid_pos

setmetatable(pos_functions, {
	__index = function (self, key)
		if not key:find(" forms$") then
			return nil
		end
		
		valid_pos = valid_pos or require "Module:table".listToSet{
			"adjective", "determiner", "noun", "numeral", "participle",
			"proper noun", "verb", "pronoun",
			
		}
		
		local pos = key:match("^(.+) forms$")
		
		if not valid_pos[pos] then
			error ("No function for the POS " .. quote(key) .. ".")
		end
		
		-- POS function for "noun forms", "verb forms", etc.
		return function(args, data)
			args = process_numbered_params(args, { "head" },
				(pos == "noun" or pos == "proper noun") and { "g" })
			
			local params = {
				head = { list = true },
			}
			if pos == "noun" or pos == "proper noun" then
				params.g = { list = true }
			elseif pos == "adjective" then
				params.deg = {}
			end
			local args = m_params.process(args, params, nil, "grc-headword", "forms")
			data.heads = args.head
			
			process_heads(data, key)
			
			if args.g then
				for _, g in ipairs(args.g) do
					if gender_names[g] then
						table.insert(data.genders, g)
					else
						error("Gender " .. quote(g) .. " is not an valid " .. canonical_name .. " gender.")
					end
				end
			end
			
			handle_degree_of_comparison(args, data, true)
			mw.logObject(data)
		end
	end
})

return export