Module:en-headword

Documentation for this module may be created at Module:en-headword/doc

local export = {}
local pos_functions = {}

local force_cat = false -- for testing; if true, categories appear in non-mainspace pages

local require = require
local require_when_needed = require("Module:require when needed")

local en_utilities_module = "Module:en-utilities"
local headword_utilities_module = "Module:headword utilities"
local headword_module = "Module:headword"
local inflection_utilities_module = "Module:inflection utilities"
local JSON_module = "Module:JSON"
local links_module = "Module:links"
local parameters_module = "Module:parameters"
local string_utilities_module = "Module:string utilities"
local table_module = "Module:table"
local utilities_module = "Module:utilities"

local iut = require_when_needed(inflection_utilities_module)

local add_links_to_multiword_term = require_when_needed(headword_utilities_module, "add_links_to_multiword_term")
local add_suffix = require_when_needed(en_utilities_module, "add_suffix")
local apply_link_modifiers = require_when_needed(headword_utilities_module, "apply_link_modifiers")
local concat = table.concat
local format_categories = require_when_needed(utilities_module, "format_categories")
local full_headword = require_when_needed(headword_module, "full_headword")
local get_link_page = require_when_needed(links_module, "get_link_page")
local insert = table.insert
local is_regular_plural = require_when_needed(en_utilities_module, "is_regular_plural")
local list_to_set = require_when_needed(table_module, "listToSet")
local remove = table.remove
local remove_links = require_when_needed(links_module, "remove_links")
local process_params = require_when_needed(parameters_module, "process")
local singularize = require_when_needed(string_utilities_module, "singularize")
local split = require_when_needed(string_utilities_module, "split")
local toJSON = require_when_needed(JSON_module, "toJSON")
local toNFD = mw.ustring.toNFD
local ulen = require_when_needed(string_utilities_module, "len")
local ulower = require_when_needed(string_utilities_module, "lower")
local umatch = require_when_needed(string_utilities_module, "match")

local lang = require("Module:languages").getByCode("en")
local langname = lang:getCanonicalName()

local function glossary_link(entry, text)
	text = text or entry
	return "[[Appendix:Glossary#" .. entry .. "|" .. text .. "]]"
end

local function track(page)
	require("Module:debug/track")("en-headword/" .. page)
	return true
end

------------------------------------------- UTILITY FUNCTIONS ------------------------------------------

-- These functions are used directly in the <> format as well as in the utility functions #2 below.

local function compute_double_last_cons_stem(term)
	local last_cons = term:match("([bcdfghjklmnpqrstvwxyzBCDFGHJKLMNPQRSTVWXYZ])$")
	if not last_cons then
		error("Verb stem '" .. term .. "' must end in a consonant to use ++")
	end
	return term .. last_cons
end

local function compute_plusplus_s_form(term, default_s_form)
	if term:find("[sz]$") then
		-- regas -> regasses, derez -> derezzes
		return compute_double_last_cons_stem(term) .. "es"
	else
		return default_s_form
	end
end


-- The main entry point.
-- This is the only function that can be invoked from a template.
function export.show(frame)

	local poscat = frame.args[1] or error("Part of speech has not been specified. Please pass parameter 1 to the module invocation.")
	
	local boolean = {type = "boolean"}
	local params = {
		["head"] = {list = true},
		["id"] = true,
		["json"] = boolean,
		["sort"] = true,
		["splithyph"] = boolean,
		["nosplithyph"] = boolean,
		["hyphspace"] = boolean,
		["nolink"] = boolean,
		["nolinkhead"] = {type = "boolean", alias_of = "nolink"},
		["nosuffix"] = boolean,
		["nomultiwordcat"] = boolean,
		["pagename"] = true, -- for testing
	}

	local pos_data = pos_functions[poscat]
	if pos_data then
		for key, val in pairs(pos_data.params) do
			params[key] = val
		end
	end

	local args = process_params(frame:getParent().args, params, nil, "en-headword", "show")

	local pagename = args.pagename or mw.loadData("Module:headword/data").pagename -- Accounts for unsupported titles.

	local user_specified_heads = args.head
	local heads = user_specified_heads
	local autohead
	if args.nolink or not pagename:find("[ '%-]") then
		autohead = pagename
	else
		local en_no_split_apostrophe_words = list_to_set{
			"one's",
			"someone's",
			"he's",
			"she's",
			"it's",
		}

		local en_include_hyphen_prefixes = list_to_set{
			-- We don't include things that are also words even though they are often (perhaps mostly) prefixes, e.g.
			-- "be", "counter", "cross", "extra", "half", "mid", "over", "pan", "under".
			"acro",
			"acousto",
			"Afro",
			"agro",
			"anarcho",
			"angio",
			"Anglo",
			"ante",
			"anti",
			"arch",
			"auto",
			"bi",
			"bio",
			"cis",
			"co",
			"cryo",
			"crypto",
			"de",
			"demi",
			"eco",
			"electro",
			"Euro",
			"ex",
			"Greco",
			"hemi",
			"hydro",
			"hyper",
			"hypo",
			"infra",
			"Indo",
			"inter",
			"intra",
			"Judeo",
			"macro",
			"meta",
			"micro",
			"mini",
			"multi",
			"neo",
			"neuro",
			"non",
			"para",
			"peri",
			"post",
			"pre",
			"pro",
			"proto",
			"pseudo",
			"re",
			"semi",
			"sub",
			"super",
			"trans",
			"un",
			"vice",
		}

		local function is_english(term)
			local title = mw.title.new(term)
			if title and title.exists then
				local content = title:getContent()
				if content and content:find("==English==\n") then
					return true
				end
			end
			return false
		end

		local function en_split_hyphen_when_space(word)
			if not word:find("%-") then
				return nil
			end
			if args.hyphspace then
				return "[[" .. word:gsub("%-", " ") .. "|" .. word .. "]]"
			end
			if args.nosplithyph then
				return "[[" .. word .. "]]"
			end
			if not args.splithyph then
				local space_word = word:gsub("%-", " ")
				if is_english(space_word) then
					return "[[" .. space_word .. "|" .. word .. "]]"
				end
				if is_english(word) then
					return "[[" .. word .. "]]"
				end
			end
			return nil
		end

		local function en_split_apostrophe(word)
			local base = word:match("^(.*)'s$")
			if base then
				return "[[" .. base .. "]][[-'s|'s]]"
			end
			base = word:match("^(.*)'$")
			if base then
				if base:find("s$") then
					local sg = singularize(base)
					if is_english(sg) then
						return "[[" .. sg .. "|" .. base .. "]][[-'|']]"
					end
				end
				return "[[" .. base .. "]][[-'|']]"
			end
			return "[[" .. word .. "]]"
		end

		autohead = add_links_to_multiword_term(pagename, {
			split_hyphen_when_space = en_split_hyphen_when_space,
			split_apostrophe = en_split_apostrophe,
			no_split_apostrophe_words = en_no_split_apostrophe_words,
			include_hyphen_prefixes = en_include_hyphen_prefixes,
		})
	end

	if #heads == 0 then
		heads = {autohead}
	else
		for i, head in ipairs(heads) do
			if head:find("^~") then
				head = apply_link_modifiers(autohead, head:sub(2))
				heads[i] = head
			end
			if head == autohead then
				track("redundant-head")
			end
		end
	end

	local data = {
		lang = lang,
		pos_category = poscat,
		categories = {},
		heads = heads,
		user_specified_heads = user_specified_heads,
		no_redundant_head_cat = #user_specified_heads == 0,
		inflections = {},
		nomultiwordcat = args.nomultiwordcat,
		sort_key = args.sort,
		pagename = args.pagename,
		-- This is always set, and in the case of unsupported titles, it's the displayed version (e.g. 'C|N>K' instead of
		-- 'Unsupported titles/C through N to K').
		displayed_pagename = pagename,
		id = args.id,
		force_cat_output = force_cat,
	}

	local is_suffix = false
	if not args.nosuffix and pagename:find("^%-") and not pagename:find("^%-%-") and poscat ~= "suffix forms" then
		is_suffix = true
		data.pos_category = "suffixes"
		local singular_poscat = singularize(poscat)
		insert(data.categories, langname .. " " .. singular_poscat .. "-forming suffixes")
		insert(data.inflections, {label = singular_poscat .. "-forming suffix"})
	end

	if pos_data then
		pos_data.func(args, data, is_suffix)
	end

	local extra_categories = {}
	if pagename:find("[Qq][^Uu]") or pagename:find("[Qq]$") then
		insert(data.categories, langname .. " words containing Q not followed by U")
	end
	-- toNFD performs decomposition, so letters that decompose to an ASCII
	-- vowel and a diacritic, such as é, are counted as vowels anddo not do not
	-- need to be included in the pattern.
	if not umatch(ulower(toNFD(pagename)), "[aeiouyæœøəªºαεηιουω]") then
		insert(data.categories, langname .. " words without vowels")
	end
	if pagename:find("yre$") then
		insert(data.categories, langname .. ' words ending in "-yre"')
	end
	if not pagename:find(" ") and ulen(pagename) >= 25 then
		insert(extra_categories, "Long " .. langname .. ' words')
	end
	if pagename:find("^[^aeiou ]*a[^aeiou ]*e[^aeiou ]*i[^aeiou ]*o[^aeiou ]*u[^aeiou ]*$") then
		insert(data.categories, langname .. ' words that use all vowels in alphabetical order')
	end

	if args.json then
		return toJSON(data)
	end

	return full_headword(data)
		.. (#extra_categories > 0
			and format_categories(extra_categories, lang, args.sort)
			or "")
end


-- This function does the common work between adjectives and adverbs
local function make_comparatives(params, data)
	local comp_parts = {label = glossary_link("comparative"), accel = {form = "comparative"}}
	local sup_parts = {label = glossary_link("superlative"), accel = {form = "superlative"}}
	local pagename = data.displayed_pagename

	if #params == 0 then
		insert(params, {"more"})
	end

	-- Go over each parameter given and create a comparative and superlative
	-- form.
	for i, val in ipairs(params) do
		local comp = val[1]
		local comp_qual = val[2]
		local sup = val[3]
		local sup_qual = val[4]
		local comp_part, sup_part

		if comp == "more" and pagename ~= "many" and pagename ~= "much" then
			comp_part = "more [[" .. pagename .. "]]"
			sup_part = sup or "most [[" .. pagename .. "]]"
		elseif comp == "further" and pagename ~= "far" then
			comp_part = "further [[" .. pagename .. "]]"
			sup_part = sup or "furthest [[" .. pagename .. "]]"
		elseif comp == "er" then
			-- Add the "-er" and "-est" suffixes.
			comp_part = add_suffix(pagename, "r")
			sup_part = sup or add_suffix(pagename, "st.superlative")
		elseif comp == "ier" then
			if pagename:sub(-1) ~= "y" then
				error("Can't specify 'ier' comparative unless the term ends with 'y'.")
			end
			comp_part = pagename:gsub("e?y$", "ier")
			sup_part = sup or pagename:gsub("e?y$", "iest")
		elseif comp == "-" or sup == "-" then
			-- Allowing '-' makes it more flexible to not have some forms
			if comp ~= "-" then
				comp_part = comp
			end
			if sup ~= "-" then
				sup_part = sup
			end
		else
			-- If the full comparative was given, but no superlative, then
			-- create it by replacing the ending -er with -est.
			if not sup then
				if comp:sub(-2) == "er" then
					sup = comp:sub(1, -3) .. "est"
				else
					error("The superlative of \"" .. comp .. "\" cannot be generated automatically. Please provide it with the \"sup" .. (i == 1 and "" or i) .. "=\" parameter.")
				end
			end

			comp_part = comp
			sup_part = sup
		end

		if comp_part then
			insert(comp_parts, {term = comp_part, q = {comp_qual}})
		end
		if sup_part then
			insert(sup_parts, {term = sup_part, q = {sup_qual}})
		end
	end

	insert(data.inflections, comp_parts)
	insert(data.inflections, sup_parts)
end


local function make_heads_definite(args, data)
	if args.def == "~" then
		local newheads = {}
		for _, head in ipairs(data.heads) do
			insert(newheads, head)
			insert(newheads, "the " .. head)
		end
		data.heads = newheads
	else
		for i, head in ipairs(data.heads) do
			data.heads[i] = "the " .. head
		end
	end
end


local function non_op()
end


pos_functions["adjectives"] = {
	params = {
		[1] = {list = true, allow_holes = true},
		["def"] = true,
		["the"] = {alias_of = "def"},
		["comp_qual"] = {list = "comp\1_qual", allow_holes = true},
		["sup"] = {list = true, allow_holes = true},
		["sup_qual"] = {list = "sup\1_qual", allow_holes = true},
		},
	func = function(args, data)
		local shift = 0
		local is_not_comparable = false
		local is_comparative_only = false

		if args.def then
			make_heads_definite(args, data)
		end

		-- If the first parameter is ?, then don't show anything, just return.
		if args[1][1] == "?" then
			return
		-- If the first parameter is -, then move all parameters up one position.
		elseif args[1][1] == "-" then
			shift = 1
			is_not_comparable = true
		-- If the only argument is +, then remember this and clear parameters
		elseif args[1][1] == "+" and args[1].maxindex == 1 then
			shift = 1
			is_comparative_only = true
		end

		-- Gather all the comparative and superlative parameters.
		local params = {}

		for i = 1, args[1].maxindex - shift do
			local comp = args[1][i + shift]
			local comp_qual = args["comp_qual"][i + shift]
			local sup = args["sup"][i]
			local sup_qual = args["sup_qual"][i + shift]

			if comp or sup then
				insert(params, {comp, comp_qual, sup, sup_qual})
			end
		end

		if shift == 1 then
			-- If the first parameter is "-" but there are no parameters,
			-- then show "not comparable" only and return.
			-- If there are parameters, then show "not generally comparable"
			-- before the forms.
			if #params == 0 then
				if is_not_comparable then
					insert(data.inflections, {label = "not " .. glossary_link("comparable")})
					insert(data.categories, langname .. " uncomparable adjectives")
					return
				end
				if is_comparative_only then
					insert(data.inflections, {label = glossary_link("comparative") .. " form only"})
					insert(data.categories, langname .. " comparative-only adjectives")
					return
				end
			else
				insert(data.inflections, {label = "not generally " .. glossary_link("comparable")})
			end
		end

		-- Process the parameters
		make_comparatives(params, data)
	end
}

pos_functions["adverbs"] = {
	params = {
		[1] = {list = true, allow_holes = true},
		["comp_qual"] = {list = "comp\1_qual", allow_holes = true},
		["sup"] = {list = true, allow_holes = true},
		["sup_qual"] = {list = "sup\1_qual", allow_holes = true},
		},
	func = function(args, data)
		local shift = 0

		-- If the first parameter is ?, then don't show anything, just return.
		if args[1][1] == "?" then
			return
		-- If the first parameter is -, then move all parameters up one position.
		elseif args[1][1] == "-" then
			shift = 1
		end

		-- Gather all the comparative and superlative parameters.
		local params = {}

		for i = 1, args[1].maxindex - shift do
			local comp = args[1][i + shift]
			local comp_qual = args["comp_qual"][i + shift]
			local sup = args["sup"][i]
			local sup_qual = args["sup_qual"][i + shift]

			if comp or sup then
				insert(params, {comp, comp_qual, sup, sup_qual})
			end
		end

		if shift == 1 then
			-- If the first parameter is "-" but there are no parameters,
			-- then show "not comparable" only and return. If there are parameters,
			-- then show "not generally comparable" before the forms.
			if #params == 0 then
				insert(data.inflections, {label = "not " .. glossary_link("comparable")})
				insert(data.categories, langname .. " uncomparable adverbs")
				return
			else
				insert(data.inflections, {label = "not generally " .. glossary_link("comparable")})
			end
		end

		-- Process the parameters
		make_comparatives(params, data)
	end
}

pos_functions["conjunctions"] = {
	params = {
		[1] = { alias_of = "head" },
	},
	func = non_op,
}

pos_functions["interjections"] = {
	params = {
		[1] = { alias_of = "head" },
	},
	func = non_op,
}

local function escape(str)
	return (str:gsub("\\([:#])", "\\\\%1")
		:gsub("[:#]", "\\%0"))
end

local function canonicalize_plural(pl, pagename, pos)
	if pl == "+" then
		return escape(add_suffix(pagename, "s.plural", pos))
	elseif pl == "++" then
		return escape(compute_plusplus_s_form(pagename, add_suffix(pagename, "s.plural", pos)))
	elseif pl == "*" then
		return escape(pagename)
	elseif pl == "ies" then
		if pagename:sub(-1) == "y" then
			return escape(pagename:gsub("e?y$", pl))
		end
		error("Can't specify 'ies' plural unless the term ends with 'y'.")
	elseif pl == "s" or pl == "es" or pl == "'s" then
		return escape(pagename .. pl)
	end
end

local function do_nouns(args, data, pos)
	local pagename = data.displayed_pagename
	pos = pos or "noun"

	local function gather_inflections_with_quals(infl_field, qual_field, label)
		-- Gather all the plural parameters from the numbered parameters.
		local infls = {}
		if label then
			infls.label = label
		end

		for i, infl in ipairs(args[infl_field]) do
			local qual = args[qual_field][i]

			if qual then
				insert(infls, {term = infl, q = {qual}})
			else
				insert(infls, infl)
			end
		end

		return infls
	end

	if args.def then
		make_heads_definite(args, data)
	end

	local plurals = gather_inflections_with_quals(1, "plqual")

	if plurals[1] == "p" then
		-- plurale tantum
		if #plurals > 1 then
			error("With plurale tantum noun, can't specify more than one plural")
		end
		data.genders = {"p"} -- this should auto-insert the correct 'pluralia tantum' category
		if #args.sg > 0 then
			insert(data.inflections, {label = "normally plural"})
			insert(data.inflections, gather_inflections_with_quals("sg", "sgqual", "singular"))
		else
			insert(data.inflections, {label = "plural only"})
		end
		if #args.attr > 0 then
			insert(data.inflections, gather_inflections_with_quals("attr", "attrqual", "attributive"))
		end
		return
	end

	local need_default_plural = pos == "noun"
	if plurals[1] == "-" then
		-- Uncountable noun; may occasionally have a plural
		remove(plurals, 1)  -- Remove the "-"
		insert(data.categories, "Nomi tal-massa (" .. langname .. ")")

		-- If plural forms were given explicitly, then show "usually"
		if #plurals > 0 then
			insert(data.inflections, {label = "usually " .. glossary_link("uncountable")})
			insert(data.categories, "Nomi tal-għadd (" .. langname .. ")")
		else
			insert(data.inflections, {label = glossary_link("uncountable")})
		end
		need_default_plural = false
	elseif plurals[1] == "~" then
		-- Mixed countable/uncountable noun, always has a plural
		remove(plurals, 1)  -- Remove the "~"
		insert(data.inflections, {label = glossary_link("countable") .. " and " .. glossary_link("uncountable")})
		insert(data.categories, "Nomi tal-massa (" .. langname .. ")")
		insert(data.categories, "Nomi tal-għadd (" .. langname .. ")")

		-- If no plural was given, add a default one now
		if #plurals == 0 then
			plurals[1] = escape(add_suffix(pagename, "s.plural", pos))
		end
	elseif pos == "proper noun" then
		-- For proper nouns, the default is uncountable
		insert(data.categories, "Nomi tal-massa (" .. langname .. ")")
	else
		-- For common nouns, the default is countable, has a plural
		insert(data.categories, "Nomi tal-għadd (" .. langname .. ")")
	end
	-- Plural is unknown
	if plurals[1] == "?" then
		remove(plurals, 1)  -- Remove the "?"
		-- Not desired; see [[Wiktionary:Tea_room/2021/August#"Plural unknown or uncertain"]]
		-- insert(data.inflections, {label = "plural unknown or uncertain"})
		insert(data.categories, langname .. " nouns with unknown or uncertain plurals")
		if #plurals > 0 then
			error("Can't specify explicit plurals along with '?' for unknown/uncertain plural")
		end
		return
	end
	-- Plural is not attested
	if plurals[1] == "!" then
		remove(plurals, 1)  -- Remove the "!"
		insert(data.inflections, {label = "plural not attested"})
		insert(data.categories, langname .. " nouns with unattested plurals")
		if #plurals > 0 then
			error("Can't specify explicit plurals along with '!' for unattested plural")
		end
		return
	end
	-- If no plural was given, maybe add a default one, otherwise (when "-" was given) return.
	if #plurals == 0 then
		if not need_default_plural then
			return
		end
		plurals[1] = escape(add_suffix(pagename, "s.plural", pos))
	end

	-- There are plural forms to show, so show them.
	plurals.label = "plural"
	plurals.accel = {form = "p"}
	local irregular, indeclinable
	for i, pl in ipairs(plurals) do
		local pl_type = type(pl)
		local pl_term = pl_type == "table" and pl.term or pl
		local canon_pl = canonicalize_plural(pl_term, pagename, pos)
		if canon_pl then
			pl_term = canon_pl
			if pl_type == "table" then
				pl.term = pl_term
			else
				plurals[i] = pl_term
			end
		end
		pl_term = get_link_page(pl_term, lang)
		if not (pagename:find(" ") or is_regular_plural(pl_term, pagename)) then
			irregular = true
			if pl_term == pagename then
				indeclinable = true
			end
		end
	end
	if irregular then
		insert(data.categories, langname .. " nouns with irregular plurals")
	end
	if indeclinable then
		insert(data.categories, langname .. " indeclinable nouns")
	end
	
	insert(data.inflections, plurals)
end


-- Return the parameters to be used for nouns and proper nouns. Currently the same.
local function get_noun_params(is_proper)
	return {
		[1] = {list = true, disallow_holes = true},
		["def"] = true,
		["the"] = {alias_of = "def"},
		["pl\1qual"] = {list = true, allow_holes = true},
		-- The following four only used for pluralia tantum (1=p)
		["sg"] = {list = true, disallow_holes = true},
		["sg\1qual"] = {list = true, allow_holes = true},
		["attr"] = {list = true, disallow_holes = true},
		["attr\1qual"] = {list = true, allow_holes = true},
	}
end


pos_functions["nouns"] = {
	params = get_noun_params(false),
	func = do_nouns,
}

pos_functions["proper nouns"] = {
	params = get_noun_params("is proper"),
	func = function(args, data) return do_nouns(args, data, "proper noun") end,
}


local function base_default_verb_forms(verb)
	return escape(add_suffix(verb, "s.verb")), escape(add_suffix(verb, "ing")), escape(add_suffix(verb, "d"))
end


local function default_verb_forms(verb)
	local full_s_form, full_ing_form, full_ed_form = base_default_verb_forms(verb)
	if verb:find(" ") then
		local first, rest = verb:match("^(.-)( .*)$")
		local first_s_form, first_ing_form, first_ed_form = base_default_verb_forms(first)
		return full_s_form, full_ing_form, full_ed_form, first_s_form .. rest, first_ing_form .. rest, first_ed_form .. rest
	else
		return full_s_form, full_ing_form, full_ed_form, nil, nil, nil
	end
end


pos_functions["verbs"] = {
	params = {
		[1] = {list = "pres_3sg", allow_holes = true},
		["pres_3sg_qual"] = {list = "pres_3sg\1_qual", allow_holes = true},
		[2] = {list = "pres_ptc", allow_holes = true},
		["pres_ptc_qual"] = {list = "pres_ptc\1_qual", allow_holes = true},
		[3] = {list = "past", allow_holes = true},
		["past_qual"] = {list = "past\1_qual", allow_holes = true},
		[4] = {list = "past_ptc", allow_holes = true},
		["past_ptc_qual"] = {list = "past_ptc\1_qual", allow_holes = true},
		["noautolinkverb"] = {type = "boolean"},
		},
	func = function(args, data)
		-- Get parameters
		local par1 = args[1][1]
		local par2 = args[2][1]
		local par3 = args[3][1]
		local par4 = args[4][1]

		local pres_3sgs, pres_ptcs, pasts, past_ptcs

		local pagename = data.displayed_pagename

		------------------------------------------- UTILITY FUNCTIONS #2 ------------------------------------------

		-- These functions are used in both in the separate-parameter format and in the override params such as past_ptc2=. 

		local new_default_s, new_default_ing, new_default_ed, split_default_s, split_default_ing, split_default_ed =
			default_verb_forms(pagename)

		local function compute_double_last_cons_stem_of_split_verb(verb, ending)
			local first, rest = verb:match("^(.-)( .*)$")
			if not first then
				error("Verb '" .. verb .. "' must have a space in it to use ++*")
			end
			local last_cons = first:match("([bcdfghjklmnpqrstvwxyzBCDFGHJKLMNPQRSTVWXYZ])$")
			if not last_cons then
				error("First word '" .. first .. "' must end in a consonant to use ++*")
			end
			return first .. last_cons .. ending .. rest
		end

		local function check_non_nil_star_form(form)
			if form == nil then
				error("Verb '" .. pagename .. "' must have a space in it to use * or ++*")
			end
			return form
		end

		local function sub_tilde(form)
			if not form then
				return nil
			end
			local retval = form:gsub("~", pagename) -- discard second return value
			return retval
		end

		local function canonicalize_s_form(form)
			if form == "+" then
				return new_default_s
			elseif form == "*" then
				return check_non_nil_star_form(split_default_s)
			elseif form == "++" then
				return compute_plusplus_s_form(pagename, new_default_s)
			elseif form == "++*" then
				if pagename:find("^[^ ]*[sz] ") then
					return compute_double_last_cons_stem_of_split_verb(pagename, "es")
				else
					return check_non_nil_star_form(split_default_s)
				end
			else
				return sub_tilde(form)
			end
		end

		local function canonicalize_ing_form(form)
			if form == "+" then
				return new_default_ing
			elseif form == "*" then
				return check_non_nil_star_form(split_default_ing)
			elseif form == "++" then
				return compute_double_last_cons_stem(pagename) .. "ing"
			elseif form == "++*" then
				return compute_double_last_cons_stem_of_split_verb(pagename, "ing")
			else
				return sub_tilde(form)
			end
		end

		local function canonicalize_ed_form(form)
			if form == "+" then
				return new_default_ed
			elseif form == "*" then
				return check_non_nil_star_form(split_default_ed)
			elseif form == "++" then
				return compute_double_last_cons_stem(pagename) .. "ed"
			elseif form == "++*" then
				return compute_double_last_cons_stem_of_split_verb(pagename, "ed")
			else
				return sub_tilde(form)
			end
		end
		
		local function canonicalize_en_form(form)
			if form == "n" then
				return add_suffix(pagename, "n")
			end
			return canonicalize_ed_form(form)
		end

		--------------------------------- MAIN PARSING/CONJUGATING CODE --------------------------------

		local past_ptcs_given

		if par1 and par1:find("<") then

			-------------------------- ANGLE-BRACKET FORMAT --------------------------

			if par2 or par3 or par4 then
				error("Can't specify 2=, 3= or 4= when 1= contains angle brackets: " .. par1)
			end
			-- In the angle bracket format, we always copy the full past tense specs to the past participle
			-- specs if none of the latter are given, so act as if the past participle is always given.
			-- There is a separate check to see if the past tense and past participle are identical, in any case.
			past_ptcs_given = true

			-- (1) Parse the indicator specs inside of angle brackets.

			local function parse_indicator_spec(angle_bracket_spec)
				local inside = angle_bracket_spec:match("^<(.*)>$")
				assert(inside)
				local segments = iut.parse_balanced_segment_run(inside, "[", "]")
				local comma_separated_groups = iut.split_alternating_runs(segments, ",")
				if #comma_separated_groups > 4 then
					error("Too many comma-separated parts in indicator spec: " .. angle_bracket_spec)
				end

				local function fetch_qualifiers(separated_group)
					local qualifiers
					for j = 2, #separated_group - 1, 2 do
						if separated_group[j + 1] ~= "" then
							error("Extraneous text after bracketed qualifiers: '" .. concat(separated_group) .. "'")
						end
						if not qualifiers then
							qualifiers = {}
						end
						insert(qualifiers, separated_group[j])
					end
					return qualifiers
				end

				local function fetch_specs(comma_separated_group)
					if not comma_separated_group then
						return {{}}
					end
					local specs = {}

					local colon_separated_groups = iut.split_alternating_runs(comma_separated_group, ":")
					for _, colon_separated_group in ipairs(colon_separated_groups) do
						local form = colon_separated_group[1]
						if form == "*" or form == "++*" then
							error("* and ++* not allowed inside of indicator specs: " .. angle_bracket_spec)
						end
						if form == "" then
							form = nil
						end
						insert(specs, {form = form, q = fetch_qualifiers(colon_separated_group)})
					end
					return specs
				end

				local s_specs = fetch_specs(comma_separated_groups[1])
				local ing_specs = fetch_specs(comma_separated_groups[2])
				local ed_specs = fetch_specs(comma_separated_groups[3])
				local en_specs = fetch_specs(comma_separated_groups[4])
				for _, spec in ipairs(s_specs) do
					if spec.form == "++" and #ing_specs == 1 and not ing_specs[1].form and not ing_specs[1].q
						and #ed_specs == 1 and not ed_specs[1].form and not ed_specs[1].q then
						ing_specs[1].form = "++"
						ed_specs[1].form = "++"
						break
					end
				end

				return {
					forms = {},
					s_specs = s_specs,
					ing_specs = ing_specs,
					ed_specs = ed_specs,
					en_specs = en_specs,
				}
			end

			local parse_props = {
				parse_indicator_spec = parse_indicator_spec,
			}
			local alternant_multiword_spec = iut.parse_inflected_text(par1, parse_props)

			-- (2) Check for user-specified brackets; remove any links from the lemma, but remember the original
			--     form so we can use it below in the 'lemma_linked' form.

			-- Check to see if there are brackets in the pre-text or post-text. If so, use the linked lemma (with the
			-- verb autolinked unless noautolinkverb is given). Otherwise, use the default headword algorithm.
			local function check_bracket(val)
				if val:find("%[%[") then
					alternant_multiword_spec.saw_bracket = true
				end
			end
			for _, alternant_or_word_spec in ipairs(alternant_multiword_spec.alternant_or_word_specs) do
				check_bracket(alternant_or_word_spec.before_text)
				if alternant_or_word_spec.alternants then
					for _, multiword_spec in ipairs(alternant_or_word_spec.alternants) do
						for _, word_spec in ipairs(multiword_spec.word_specs) do
							check_bracket(word_spec.before_text)
						end
						check_bracket(multiword_spec.post_text)
					end
				end
			end
			check_bracket(alternant_multiword_spec.post_text)

			iut.map_word_specs(alternant_multiword_spec, function(base)
				if base.lemma == "" then
					base.lemma = pagename
				end
				base.orig_lemma = base.lemma
				base.lemma = remove_links(base.lemma)
				if args.noautolinkverb or base.orig_lemma:find("%[%[") then
					base.linked_lemma = base.orig_lemma
				else
					base.linked_lemma = "[[" .. base.orig_lemma .. "]]"
				end
			end)

			-- (3) Conjugate the verbs according to the indicator specs parsed above.

			local all_verb_slots = {
				lemma = "infinitive",
				lemma_linked = "infinitive",
				s_form = "3|s|pres",
				ing_form = "pres|ptcp",
				ed_form = "past",
				en_form = "past|ptcp",
			}
			local function conjugate_verb(base)
				local def_s_form, def_ing_form, def_ed_form = base_default_verb_forms(base.lemma)

				local function process_specs(slot, specs, default_form, canonicalize_plusplus)
					for _, spec in ipairs(specs) do
						local form = spec.form
						if not form or form == "+" then
							form = default_form
						elseif form == "++" then
							form = canonicalize_plusplus()
						end
						-- If there's a ~ in the form, substitute it with the lemma,
						-- but make sure to first replace % in the lemma with %% so that
						-- it doesn't get interpreted as a capture replace expression.
						if form:find("~") then
							-- Assign to a var because gsub returns multiple values.
							local subbed_lemma = base.lemma:gsub("%%", "%%%%")
							form = form:gsub("~", subbed_lemma)
						end
						-- If the form is -, don't insert any forms, which will result
						-- in there being no overall forms (in fact it will be nil).
						-- We check for that down below and substitute a single "-" as
						-- the form, which in turn gets turned into special labels like
						-- "no present participle".
						if form ~= "-" then
							iut.insert_form(base.forms, slot, {form = form, footnotes = spec.q})
						end
					end
				end

				process_specs("s_form", base.s_specs, def_s_form,
					function() return compute_plusplus_s_form(base.lemma, def_s_form) end)
				process_specs("ing_form", base.ing_specs, def_ing_form,
					function() return compute_double_last_cons_stem(base.lemma) .. "ing" end)
				process_specs("ed_form", base.ed_specs, def_ed_form,
					function() return compute_double_last_cons_stem(base.lemma) .. "ed" end)

				-- If the -en spec is completely missing, substitute the -ed spec in its entirely.
				-- Otherwise, if individual -en forms are missing or use +, we will substitute the
				-- default -ed form, as with the -ed spec.
				local en_specs = base.en_specs
				if #en_specs == 1 and not en_specs[1].form and not en_specs[1].q then
					en_specs = base.ed_specs
				end

				process_specs("en_form", en_specs, def_ed_form,
					function() return compute_double_last_cons_stem(base.lemma) .. "ed" end)

				iut.insert_form(base.forms, "lemma", {form = base.lemma})
				-- Add linked version of lemma for use in head=. We write this in a general fashion in case
				-- there are multiple lemma forms (which isn't possible currently at this level, although it's
				-- possible overall using the ((...,...)) notation).
				iut.insert_forms(base.forms, "lemma_linked", iut.map_forms(base.forms.lemma, function(form)
					if form == base.lemma and base.linked_lemma:find("%[%[") then
						return base.linked_lemma
					else
						return form
					end
				end))
			end

			local inflect_props = {
				slot_table = all_verb_slots,
				inflect_word_spec = conjugate_verb,
			}
			iut.inflect_multiword_or_alternant_multiword_spec(alternant_multiword_spec, inflect_props)

			-- (4) Fetch the forms and put the conjugated lemmas in data.heads if not explicitly given.

			local function fetch_forms(slot)
				local forms = alternant_multiword_spec.forms[slot]
				-- See above. This should only occur if the user explicitly used -
				-- for a spec.
				if not forms or #forms == 0 then
					forms = {{form = "-"}}
				end
				return forms
			end

			pres_3sgs = fetch_forms("s_form")
			pres_ptcs = fetch_forms("ing_form")
			pasts = fetch_forms("ed_form")
			past_ptcs = fetch_forms("en_form")
			-- Use the "linked" form of the lemma as the head if no head= explicitly given and the user specified brackets
			-- in one of the lemmas. Otherwise we use the default headword-linking algorithm.
			if #data.user_specified_heads == 0 and alternant_multiword_spec.saw_bracket then
				data.heads = {}
				for _, lemma_obj in ipairs(alternant_multiword_spec.forms.lemma_linked) do
					local quals, refs = iut.convert_footnotes_to_qualifiers_and_references(lemma_obj.footnotes)
					insert(data.heads, {term = lemma_obj.form, q = quals, refs = refs})
				end
			end
		else
			-------------------------- SEPARATE-PARAM FORMAT --------------------------

			local pres_3sg, pres_ptc, past

			if par1 and not (par2 or par3) then
				-- Use of a single parameter other than "++", "*" or "++*" is now the "legacy" format,
				-- and no longer supported.
				if par1 == "es" or par1 == "ies" or par1 == "d" then
					error("Legacy parameter 1=es/ies/d no longer supported, just use 'en-verb' without params")
				elseif par1 == "++" or par1 == "*" or par1 == "++*" then
					pres_3sg = canonicalize_s_form(par1)
					pres_ptc = canonicalize_ing_form(par1)
					past = canonicalize_ed_form(par1)
				else
					error("Legacy parameter 1=STEM no longer supported, just use 'en-verb' without params")
				end
			else
				if par2 then
					track("xxx2")
				end
				if par3 then
					track("xxx3")
				end
			end

			if not pres_3sg or not pres_ptc or not past then
				-- Either all three should be set above, or none of them.
				assert(not pres_3sg and not pres_ptc and not past)

				if par1 then
					pres_3sg = canonicalize_s_form(par1)
				else
					pres_3sg = new_default_s
				end

				if par2 then
					pres_ptc = canonicalize_ing_form(par2)
				else
					pres_ptc = new_default_ing
				end

				if par3 then
					past = canonicalize_ed_form(par3)
				else
					past = new_default_ed
				end
			end

			local past_ptc
			if par4 then
				past_ptcs_given = true
				past_ptc = canonicalize_en_form(par4)
				track("xxx4")
			else
				past_ptc = past
			end

			pres_3sgs = {{form = pres_3sg}}
			pres_ptcs = {{form = pres_ptc}}
			pasts = {{form = past}}
			past_ptcs = {{form = past_ptc}}
		end

		------------------------------------------- HANDLE OVERRIDES ------------------------------------------

		local function strip_brackets(qualifiers)
			if not qualifiers then
				return nil
			end
			local stripped_qualifiers = {}
			for _, qualifier in ipairs(qualifiers) do
				local stripped_qualifier = qualifier:match("^%[(.*)%]$")
				if not stripped_qualifier then
					error("Internal error: Qualifier should be surrounded by brackets at this stage: " .. qualifier)
				end
				insert(stripped_qualifiers, stripped_qualifier)
			end
			return stripped_qualifiers
		end

		local function collect_forms(label, accel_form, defaults, overrides, override_qualifiers, canonicalize)
			if defaults[1].form == "-" then
				return {label = "no " .. label}
			else
				local into_table = {label = label, accel = {form = accel_form}}
				local maxindex = math.max(#defaults, overrides.maxindex)
				local qualifiers = override_qualifiers[1] and {override_qualifiers[1]} or strip_brackets(defaults[1].footnotes)
				insert(into_table, {term = defaults[1].form, q = qualifiers})

				-- Present 3rd singular
				for i = 2, maxindex do
					local override_form = canonicalize(overrides[i])

					if override_form then
						-- If there is an override such as past_ptc2=..., only use the qualifier specified
						-- using an override (past_ptc2_qual=...), if any; it doesn't make sense to combine
						-- an override form with a qualifier specified inside of angle brackets.
						insert(into_table, {term = override_form, q = {override_qualifiers[i]}})
					elseif defaults[i] then
						-- If the form comes from inside angle brackets, allow any override qualifier
						-- (past_ptc2_qual=...) to override any qualifier specified inside of angle brackets.
						-- FIXME: Maybe we should throw an error here if both exist.
						local qualifiers = override_qualifiers[i] and {override_qualifiers[i]} or strip_brackets(defaults[i].footnotes)
						insert(into_table, {term = defaults[i].form, q = qualifiers})
					end
				end

				return into_table
			end
		end

		local pres_3sg_infls = collect_forms("third-person singular simple present", "s-verb-form",
			pres_3sgs, args[1], args.pres_3sg_qual, canonicalize_s_form)
		local pres_ptc_infls = collect_forms("present participle", "ing-form",
			pres_ptcs, args[2], args.pres_ptc_qual, canonicalize_ing_form)
		local past_infls = collect_forms("simple past", "spast",
			pasts, args[3], args.past_qual, canonicalize_ed_form)
		local past_ptc_infls = collect_forms("past participle", "past|part",
			past_ptcs, args[4], args.past_ptc_qual, canonicalize_en_form)

		-- Are the past forms identical to the past participle forms? If so, we use a single
		-- combined "simple past and past participle" label on the past tense forms.
		-- We check for two conditions: Either no past participle forms were given at all, or
		-- they were given but are identical in every way (all forms and qualifiers) to the past
		-- tense forms. The former "no explicit past participle forms" check is important in the
		-- "separate-parameter" format; if past tense overrides are given and no past participle
		-- forms given, the past tense overrides should apply to the past participle as well.
		-- In the angle-bracket format, it's expected that all forms and qualifiers are specified
		-- using that format, and we explicitly copy past tense forms and qualifiers to past
		-- participle ones if the latter are omitted, so we disable to "no explicit past participle
		-- forms" check.
		if args[4].maxindex > 0 or args.past_ptc_qual.maxindex > 0 then
			past_ptcs_given = true
		end

		local identical = true

		-- For the past and past participle to be identical, there must be
		-- the same number of inflections, and each inflection must match
		-- in term and qualifiers.
		if #past_infls ~= #past_ptc_infls then
			identical = false
		else
			for key, val in ipairs(past_infls) do
				if past_ptc_infls[key].term ~= val.term then
					identical = false
					break
				else
					local quals1 = past_ptc_infls[key].q
					local quals2 = val.q
					if (not not quals1) ~= (not not quals2) then
						-- one is nil, the other is not
						identical = false
					elseif quals1 and quals2 then
						-- qualifiers present in both; each qualifier must match
						if #quals1 ~= #quals2 then
							identical = false
						else
							for k, v in ipairs(quals1) do
								if v ~= quals2[k] then
									identical = false
									break
								end
							end
						end
					end
					if not identical then
						break
					end
				end
			end
		end

		-- Insert the forms
		insert(data.inflections, pres_3sg_infls)
		insert(data.inflections, pres_ptc_infls)

		if not past_ptcs_given or identical then
			if past_ptcs[1].form == "-" then
				past_infls.label = "no simple past or past participle"
			else
				past_infls.label = "simple past and past participle"
				past_infls.accel = {form = "ed-form"}
			end
			insert(data.inflections, past_infls)
		else
			insert(data.inflections, past_infls)
			insert(data.inflections, past_ptc_infls)
		end

		if pagename:find(" ") then
			-- Check for placeholder "it"
			local words = split(pagename, " ")
			for _, word in ipairs(words) do
				if word == "it" or word == "its" or word == "it's" then
					insert(data.categories, langname .. ' terms with placeholder "it"')
					break
				end
			end

			-- Check for phrasal verbs
			local phrasal_adverbs = list_to_set{
				-- NOTE: This should only contain common phrasal adverbs, not random words like [[low]],
				-- [[adrift]], etc.
				"aback",
				"about",
				"above",
				"across",
				"after",
				"against",
				"ahead",
				"along",
				"apart",
				"around",
				"as",
				"aside",
				"at",
				"away",
				"back",
				"before",
				"behind",
				"below",
				"between",
				"beyond",
				"by",
				"down",
				"for",
				"forth",
				"from",
				"in",
				"into",
				"of",
				"off",
				"on",
				"onto",
				"out",
				"over",
				"past",
				"round",
				"through",
				"to",
				"together",
				"towards",
				"under",
				"up",
				"upon",
				"with",
				"without",
			}
			local allowed_non_adverb_words = list_to_set{
				"it",
				"one",
				"oneself",
				"someone",
			}
			local base = pagename
			local seen_adverbs = {}
			-- Only consider a verb to be phrasal if it consists of a single base verb followed exclusively by either
			-- adverbs from `phrasal_adverbs` or placeholder words from `allowed_non_adverb_words`, where at
			-- least one following word is from `phrasal_adverbs` (hence [[can it]] is not a phrasal verb).
			while true do
				local prev, word = base:match("^(.+) (.-)$")
				if not prev then
					break
				end
				if phrasal_adverbs[word] then
					insert(seen_adverbs, word)
				elseif allowed_non_adverb_words[word] then
					-- do nothing
				else
					break
				end
				base = prev
			end
			if not base:find(" ") and #seen_adverbs > 0 then
				insert(data.categories, langname .. " phrasal verbs")
				for i = #seen_adverbs, 1, -1 do
					insert(data.categories, langname .. ' phrasal verbs formed with "' .. seen_adverbs[i] ..
						'"')
				end
			end
		end
	end
}

return export