Module:Interlinear

 local p = {}
 local data = mw.loadData( 'Module:Interlinear/data' )
 local gloss_override = {} -- for custom gloss abbreviations
 local getArgs = require('Module:Arguments').getArgs
 local yesno = require('Module:Yesno')
 local lang_data = mw.loadData( 'Module:Lang/data' )

 --------------------------
 -- Almost-global variables
 --------------------------
 local glossing_type, displaying_messages, free_translation, msg, buffer

 -------------------
 -- General settings
 -------------------
 local conf = { --settings
	WordSeparator = " \n\r\t", -- Don't replace with %s as this would include non-breaking spaces
	GlossAbbrPattern = "^([Ø0-9A-Z]+)$", -- this isn't a full regex, but a Lua pattern
	-- NOTE: The following characters must be formatted for use in a pattern set.
	GlossAbbrBoundary = "-.,;:<>‹›/\\~+=%?%s%[%]()%_127円'",
	GlossExcludeTable = {I = true,}, --strings not be treated as glossing abbreviations
	GlossExcludePattern = '^[0-9][0-9]+$', -- excludes strings consisting entirely of digits
	GlossSmallCapsExclude = "^[AOPS]$", -- glossing abbreviations matching this pattern will not be rendered in small caps
	GlossingType = "label", -- if set to "label" gloss abbreviations are formatted as an <abbr> with the "label" appearing in a tooltip
						-- if set to "wikilink" the abbreviation is formatted as a wikilink to the relevant wikipedia article
						-- if set to "none" abbreviations aren't formatted at all
	ErrorCategory = "[[Category:Pages with errors in interlinear text]]",
	AmbiguousGlossCategory = "[[Category:Articles with ambiguous glossing abbreviations]]",
	MessageGlossingError = "Error(s) in interlinear glossing",
	combining_gender_numbers = "[0-9][0-9]?$", --e.g. G4 '4th gender' or CL7 'class 7'
	combining_gender_prefixes = {G = "gender", CL = "class"},
	combining_person = {["1"] = "first person", ["2"] = "second person", ["3"] = "third person",},
	combining_number = {
		S = "singular", SG = "singular",
		P = "plural", PL = "plural",
		D = "dual", DU = "dual",
		TRI = "trial", PAU = "paucal", COL = "collective",
		IN = "inclusive", INC = "inclusive", INCL = "inclusive",
		EX = "exclusive", EXC = "exclusive", EXCL = "exclusive"
	},
	combining_gender = {F = "feminine", M = "masculine", N = "neuter"},
	LowerCaseGlosses = {
		["1sg"] = true, ["2sg"] = true, ["3sg"] = true,
		["1du"] = true, ["2du"] = true, ["3du"] = true,
		["1pl"] = true, ["2pl"] = true, ["3pl"] = true,
		["Fsg"] = true, ["Fpl"] = true, ["Msg"] = true, ["Mpl"] = true,
	}, -- these are the non-all-upper-case strings that will be recognised as glossing abbreviations
	ErrorHelpLocation = "Template:Interlinear",
 }

 ---------------------
 -- CSS styles and classes
 ---------------------
 conf.style = { --CSS styles
	WordDiv = "float: left; margin-bottom: 0.3em;",
	WordMargin = "margin-right: 1em;",
	WordP = "margin: 0px;", -- the style for the word <p> elements
	GlossAbbr = "font-variant: small-caps; font-variant-numeric: lining-nums; text-transform: lowercase; ", -- won't be applied to gloss abbreviations containing lower-case characters
	HiddenText = "display: none;",
	EndDiv = "clear: left; display: block;", -- style of the <div> element at the end of the interlinear display
	ErrorMessage = "font-size: inherit",
 }
 conf.class = { --CSS classes
	Interlinear = "interlinear",
	GlossAbbr = "gloss-abbr",
	GlossAbbrAmb = "gloss-abbr-ambiguous",
	GlossAbbrError = "gloss-abbr-error",
	ErrorMessage = "error",
 }
 ---------------------
 -- Section transclusion
 ---------------------
 local page_content = nil -- lazy initilization
 local function get_section(frame, section_name)
	if page_content == nil then
		local current_title = mw.title.getCurrentTitle()
		page_content = current_title:getContent()
	end
	if page_content then
		if mw.ustring.find(page_content, section_name, 1, true) then
			return frame:preprocess('{{#section:{{FULLPAGENAME}}|' .. section_name .. '}}')
		end
	end
	return ''
 end
 ---------------------
 -- Sundry small functions
 ---------------------
 local function normalise(str)
	return mw.ustring.gsub(str,"[" .. conf.WordSeparator .. "]+"," ")
 end

 local function tidyCss(str)
	str = mw.ustring.gsub(str, '^[\"\']*(.-)[\"\']*$', "%1") -- trims quotation marks
	if mw.ustring.sub(str, -1) ~= ";" then str = str .. ";" end -- appends ";" if missing
	return str
 end

 local function highlight(text)
	if text then
		return '<span style="color:#C00;font-weight:bold;">' .. text .. '</span>'
	else return "" end
 end

 local function tone_sup(str)
	return mw.ustring.gsub(str, "([^%p%s0-9])([0-9]+)", "%1<sup>%2</sup>")
 end

 local function is_empty(str) -- returns "false" if its argument is a string containing chars other than spaces &c.
	if not str then return true end
	if mw.ustring.find(str, "[^" .. conf.WordSeparator .. "]")
		then return false
	else return true end
 end

 local function help_link (anchor)
	if anchor then
		return " ([[" .. conf.ErrorHelpLocation .. "#" .. anchor .. "|help]])"
	else return "" end
 end

 -- the following is part of a trial implementation of automatic transliteration:
 local function transliterate (str, lang_from, lang_to, scheme)
	local lookup = {grc = {module = 'Module:Ancient Greek', funct = "transliterate", } }
	if not lang_from then
		msg:add("error", "Source language for transliteration is not set")
	else
		local t = lookup[lang_from]
		if t then
			local module = require(t.module)
			return module[t.funct](str)
		else msg:add("error", "Can't find transliterator for language '" .. lang_from .. "'")
		end
	end
	return ""
 end -- end of trial block

 --------------------
 -- The following two functions update the glossing settings based on the received
 -- template arguments. set_global_glossing_settings() updates the global settings
 -- that are valid for all gloss abbreviations. set_glossing_type()
 -- returns the glossing type, which can vary between the different lines.
 --------------------
 local function set_global_glossing_settings(a)
	local style = ""
	if a.style then style = tidyCss(a.style) end
	if a.underline == "no" then
		style = style .. "text-decoration: none;" end
	if a.small_caps == "no" then
		style = style .. "font-variant:normal; text-transform: none;" end
	if style ~= "" then conf.style.GlossAbbr = conf.style.GlossAbbr .. style end
 end

 local function set_glossing_type(glossing)
	if glossing then
		local GlossingType
		glossing = mw.ustring.lower(mw.text.trim(glossing))
		if mw.ustring.find(glossing, 'link') then
			GlossingType = "wikilink"
		elseif mw.ustring.find(glossing, 'label')
			or mw.ustring.find(glossing, 'no link') then
			GlossingType = 'label'
		elseif mw.ustring.find(glossing, 'no abbr') then
			GlossingType = "no abbr"
		elseif yesno(glossing) == false then
			GlossingType = nil
		elseif yesno(glossing) then
			GlossingType = conf.GlossingType
		else
			msg:add('error', 'Glossing type "' .. glossing .. '" not recognised') end
		return GlossingType
	else error("set_glossing_type: 'glossing' is nil or false", 2)
	end
 end

 local function set_custom_glosses(list)
	local abbs = mw.text.split(list, '[;\n\t]')
	for _,v in pairs(abbs) do
		local gloss = mw.text.split(v, ':')
		local a = mw.text.trim(gloss[1])
		if a and a ~= "" then
			gloss_override[a] = {}
			gloss_override[a].expansion = gloss[2]
			gloss_override[a].wikipage = gloss[3]
		end
	end
 end

 ---------------------
 -- The UserMessages object contains and processes error messages and warnings
 ---------------------
 local UserMessages = {errors = {}, warnings = {}, gloss_messages = {}}
 function UserMessages:add(msgtype, text, gloss)
	if msgtype == "gloss_message" then
		self.gloss_messages[gloss] = text
	elseif msgtype == "warning" then
		table.insert(self.warnings, text)
	elseif msgtype == "non-repeating error" then
		self.errors.nre = text
	elseif msgtype == "ambiguous gloss" then
		self.if_ambiguous_glosses = true
	elseif msgtype == "error" then
		table.insert(self.errors, text)
	else return error("UserMessages:add(): unknown message type", 2)
	end
 end
 function UserMessages:print_errors()
	local out = ""
	local namespace = mw.title.getCurrentTitle().namespace
	if next(self.errors) or self.warnings[1] then
		local err_span = mw.html.create("span")
		err_span:attr("style", conf.style.ErrorMessage)
		err_span:addClass(conf.class.ErrorMessage)
		for _,v in pairs(self.errors) do
			err_span:wikitext(" " .. v .. ";") end
		if namespace % 2 == 0 and namespace ~= 2 -- non-talk namespaces, excluding user pages; if modifying please update the description on the category page
			then err_span:wikitext(conf.ErrorCategory)
		end
		out = tostring(err_span)
		mw.addWarning(conf.MessageGlossingError)
	end
	if self.if_ambiguous_glosses then
		if namespace == 0 -- article namespace
			then out = out .. conf.AmbiguousGlossCategory -- this category will only track articles
		end
	end
	return out
 end
 function UserMessages:print_warnings()
	local out = ""
	-- Messages and warnings get displayed only if the page is being viewed in "preview" mode:
	if displaying_messages and (next(self.gloss_messages) or next(self.warnings)) then
		local div = mw.html.create("div")
		div:addClass("interlinear-preview-warning")
			:cssText('border: 1px solid #a2a9b1; background-color: #f8f9fa; width: 80%; padding: 0.2em;')
			:wikitext("<i>This message box is shown only in preview:</i>")
			:newline()
		for _,v in ipairs(self.warnings) do
			local p = div:tag("p")
			p:addClass(conf.class.ErrorMessage)
			p:attr("style", conf.style.ErrorMessage)
			p:wikitext(v)
		end
		if self.gloss_messages then
			div:wikitext("<p> To change any of the following default expansions, see [[Template:Interlinear/doc#Custom abbreviations|the template's documentation]]:</p>")
			end
		for _,v in pairs(self.gloss_messages) do
			div:wikitext("<p>" .. v .. "</p>")
		end
		out = out .. "\n\n" .. tostring(div)
	end
	return out
 end

 ---------------------
 -- gloss_lookup() receives a gloss abbreviation and tries to uncover its meaning.
 ---------------------
 local function gloss_lookup(a, label, wikilink)
	local _label, _wikilink, _lookup, source = nil, nil, nil, nil
	if gloss_override[a] then
		_lookup = gloss_override[a]
		source = "local"
	elseif data.abbreviations[a] then _lookup = data.abbreviations[a] end
	if _lookup and _lookup.expansion ~= "" then
		_label, _wikilink = _lookup.expansion, _lookup.wikipage
	else
		local prefix = mw.ustring.sub(a,1,1)
		local suffix = mw.ustring.sub(a,2)
		if conf.combining_person[prefix] then -- is it of the form 1PL or 3FS?
			_label = conf.combining_person[prefix]
		local _suffix = conf.combining_number[suffix] or conf.combining_gender[suffix]
			if _suffix then
				_label = _label .. ", " .. _suffix
			else
				local suffix1 = mw.ustring.sub(suffix,1,1)
				local suffix2 = mw.ustring.sub(suffix,2)
					if conf.combining_gender[suffix1]
					and conf.combining_number[suffix2] then
						_label = _label .. ", " .. conf.combining_gender[suffix1] .. ", " .. conf.combining_number[suffix2]
					else _label = nil end
			end
	elseif mw.ustring.match(suffix,conf.combining_gender_numbers) then -- cases like G4 = gender 4
		local _i,_j = mw.ustring.find(a, conf.combining_gender_numbers)
		local _pre = mw.ustring.sub(a, 1, _i - 1)
		local _suff = mw.ustring.sub(a, _i)
		if conf.combining_gender_prefixes[_pre] then
			_label = conf.combining_gender_prefixes[_pre] .. " " .. _suff
		end
	elseif prefix == "N" then -- dealing with cases like NPST = non-past
		local s = gloss_override[suffix] or data.abbreviations[suffix]
			if s ~= nil and not s.ExcludeNegation then
				_label = "non-" .. s.expansion
				_wikilink = s.wikipage
			end
			s = nil
		end
	end
	if _label == "" then _label = nil end
	if _wikilink == "" then _wikilink = nil end
	if not label then label = _label end
	if not wikilink then wikilink = _wikilink end
	return label, wikilink, source
 end

 ---------------------
 -- format_gloss() calls gloss_lookup() to find the meaning of a gloss
 -- abbreviation, which it then proceeds to format
 ---------------------
 local function format_gloss(gloss, label, wikilink)
	if string.sub(gloss,1,3) == "000" then -- checks for a common component of exposed strip markers (see [[:mw:Strip marker]])
		return gloss
	end
	local gloss2 = mw.ustring.gsub(gloss,"<.->","") -- remove any html fluff
	gloss2 = mw.ustring.gsub(gloss2, "%'%'+", "") -- remove wiki bold/italic formatting
	gloss2 = mw.text.trim(mw.ustring.upper(gloss2))
	if not (label or wikilink)
		or (not label and glossing_type == "label")
		or (not wikilink and glossing_type == "wikilink")
		then
			if glossing_type ~= "no abbr"
				then label, wikilink, source = gloss_lookup(gloss2, label, wikilink)
			end
	end
	local gloss_node
	if glossing_type == "no abbr"
		then gloss_node = mw.html.create("span")
	else gloss_node = mw.html.create("abbr") end
	gloss_node:addClass(conf.class.GlossAbbr)
	if label or wikilink then
		if not mw.ustring.match(gloss, "%l") -- excluding glosses that contain lower-case characters
			and not mw.ustring.match(gloss,conf.GlossSmallCapsExclude) -- and also excluding A, O etc. from rendering in small caps
			then gloss_node:attr("style", conf.style.GlossAbbr)
		end
		local abbr_label
		if label then abbr_label = label
			else abbr_label = wikilink end
		gloss_node:attr("title", abbr_label)
		if source ~= "local" and data.abbreviations[gloss2] then
			if data.abbreviations[gloss2].ambiguous then
				gloss_node:addClass(conf.class.GlossAbbrAmb)
					msg:add("ambiguous gloss")
				end
		end
		if glossing_type == "wikilink" and wikilink
			then gloss_node:wikitext("[[", wikilink, "|" , gloss, "]]")
			else gloss_node:wikitext(gloss) end
		if source ~= "local" and displaying_messages then -- logging gloss lookups:
			local message = ""
			if label then
				message = "assuming " .. gloss2 .. " means \"" .. abbr_label .. "\";" end
			if glossing_type == "wikilink" and wikilink then
				message = message .. " linking to [[" .. wikilink .. "]];"
			end
			msg:add("gloss_message", message, gloss)
		end
	elseif glossing_type == "no abbr"
		then gloss_node
				:attr("style", conf.style.GlossAbbr)
				:wikitext(gloss)
	else
		if displaying_messages then
			msg:add("warning", "Gloss abbreviation " .. highlight(gloss2) .. " not recognised" .. help_link("gloss abbr"))
		end
		msg:add("non-repeating error", "Unknown glossing abbreviation(s)" .. help_link("gloss abbr"))
		gloss_node
			:addClass(conf.class.GlossAbbrError)
			:addClass("error")
			:css("font-size", "100%")
			:attr("title", gloss2 .. ": glossing abbreviation not found")
			:attr("style", conf.style.ErrorMessage)
			:wikitext(gloss)
	end
	return tostring(gloss_node)
 end

 ---------------------
 -- find_gloss() parses a word into morphemes, and it calls format_gloss()
 -- for anything that looks like a glossing abbreviation.
 ---------------------
 local function find_gloss(word)
	local function scan_gloss(boundary, gloss_abbr) -- checks a morpheme if it is a gloss abbreviation
		if (mw.ustring.match(gloss_abbr, conf.GlossAbbrPattern)
			or conf.LowerCaseGlosses[gloss_abbr])
			and not (conf.GlossExcludeTable[gloss_abbr]
				or mw.ustring.match(gloss_abbr, conf.GlossExcludePattern))
			then gloss_abbr = format_gloss(gloss_abbr)
		end
		return boundary .. gloss_abbr
	end
	local word = mw.text.decode(word, true)
	if word == "I" -- for the case of the English word "I", the 1SG pronoun
		then return word end
	local pattern = "([" .. conf.GlossAbbrBoundary .. "]?)([^" .. conf.GlossAbbrBoundary .. "]+)"
	word = mw.ustring.gsub(word, pattern, scan_gloss) -- splits into morphemes
	return word
 end

 ---------------------
 -- The main purpose of the bletcherous parse() is to split a line into words and and then for each eligible word
 -- to call find_gloss(). The parser outputs the individual words (with any gloss abbreviation formatting applied).
 -- The simple job of splitting at whitespaces has been made complicated by a) the fact that the input can contain
 -- whitespaces inside the various html elements that are the result of the application of various formatting templates;
 -- and b) the need to be able to recognise the output of the template that formats custom gloss abbreviations
 -- (and hence skip passing it on to find_gloss). See talk for a suggestion about its future.
 ---------------------
 local function parse(cline, i, tags_found,ifglossing)

	local function issue_error(message, culprit)
		UserMessages:add("error", message .. ": ''" .. mw.ustring.sub(cline.whole, 1, i-1) .. "'''" .. culprit .. "'''''")
	end
	if i > cline.length then return i end --this will only be triggered if the current line has less words than line 1
	local next_step, j, _, chunk
	local probe = mw.ustring.sub(cline.whole,i,i)
	if mw.ustring.match(probe,"[" .. conf.WordSeparator .. "]") and tags_found == 0
		then next_step = i-1
	elseif probe == "[" then --Wikilink?
		if mw.ustring.sub(cline.whole,i+1,i+1) == "[" then
			_,j,chunk = mw.ustring.find(cline.whole,"(%[%[.-%]%])", i)
		else chunk = "["; j = i end --not a wikilink then
		buffer = buffer .. chunk
		next_step = parse(cline, j+1,tags_found,ifglossing)
	elseif probe == "{" and tags_found == 0 then --curly brackets enclose a sequence of words to be treated as a single unit
		_,j,chunk = mw.ustring.find(cline.whole,"(.-)(})", i+1)
		if not chunk then
			issue_error("Unclosed curly bracket", "{")
			chunk = highlight("{"); j = i
		elseif ifglossing==true then
			chunk = find_gloss(chunk)
		else
			if cline.tone_sup then chunk = tone_sup(chunk) end
		end
		buffer = buffer .. chunk
		next_step = parse(cline, j+1,tags_found,ifglossing)
	elseif probe == "<" then -- We've encountered an HTML tag. What do we do now?
		local _,j,chunk = mw.ustring.find(cline.whole,"(<.->)",i)
		if not chunk then
			issue_error("Unclosed angle bracket", "<")
			chunk = highlight("<"); j = i
		elseif mw.ustring.sub(cline.whole,i,i+1) == "</" then -- It's a CLOSING tag
			if cline.glossing
				and ifglossing==false
				and mw.ustring.match(chunk,"</abbr>")
				then ifglossing=true end
			tags_found = tags_found - 1
		elseif not mw.ustring.match(chunk, "/>$") -- It's an OPENING tag, unless it opens a self-closing element (in which case the element is ignored)
			then if ifglossing == true -- the following checks for the output of {{ggl}}:
					and mw.ustring.find(chunk, conf.class.GlossAbbr, 1, true) -- it's important that the "find" function uses literal strings and not patterns
						then ifglossing = false end
			tags_found = tags_found + 1
		end
		buffer = buffer .. chunk
		next_step = parse(cline, j+1,tags_found,ifglossing)
	else -- No HTML tags, so we only need to find where the word ends
		local _,k,chunk = mw.ustring.find(cline.whole,"(..-)([ <[])",i)
		if k then --ordinary text
			if ifglossing==true then
				buffer = buffer .. find_gloss(chunk)
			else
				if cline.tone_sup then chunk = tone_sup(chunk) end
				buffer = buffer .. chunk
			end
			next_step = parse(cline, k, tags_found, ifglossing)
		else -- reached end of string
			if ifglossing == true then
				chunk = find_gloss(mw.ustring.sub(cline.whole,i))
			else
				chunk = mw.ustring.sub(cline.whole,i)
				if cline.tone_sup then chunk = tone_sup(chunk) end
			end
			buffer = buffer .. chunk
			next_step = cline.length
		end
	end
	return next_step
 end
 --------------------
 -- The following function is called by Template:gcl and is used for formatting an individual glossing abbreviation
 --------------------
 function p.gcl(frame)
	local args = getArgs(frame,{
		trim = true,
		removeBlanks = false,
		parentOnly = true,
		wrappers = {'Template:Grammatical category label'},
	})
	msg = UserMessages
	set_global_glossing_settings{style = args.style, underline = args.underline, small_caps = args['small-caps']}
	if not args.glossing then
		glossing_type = conf.GlossingType -- a global variable
	else glossing_type = set_glossing_type(args.glossing)
	end
	local gloss, label, wikilink = args[1], args[2], args[3]
	if not gloss then UserMessages:add("error", "No gloss supplied")
		return UserMessages:print() end
	if wikilink and not args.glossing then -- if a wikilink is supplied and glossing isn't set to 'label'...
		glossing_type = 'wikilink' end -- .. then the wikilink will be formatted as such
	if label == "" then label = nil end
	if wikilink == "" then wikilink = nil end
	local result = format_gloss(gloss, label, wikilink)
	return result
 end

 --------------------
 -- The following is the function called by Template:Interlinear.
 -- It processes the template arguments, then calls parse() to split the input lines into words
 -- and it then builds the output html.
 --------------------
 function p.interlinearise(frame)
 ---------------------
 -- Prepare arguments
 ---------------------
	local if_auto_translit = false
	local args = getArgs(frame, { -- configuration for Module:Arguments
		trim = true,
		removeBlanks = false,
		parentFirst = true,
		wrappers = {'Template:Interlinear', 'Template:Fs interlinear'},
	})
	local template_name = frame:getParent():getTitle()
	if template_name == 'Template:Fs interlinear' then
		args.italics1 = args.italics1 or "no"
		args.italics2 = args.italics2 or "yes"
		args.glossing3 = args.glossing3 or "yes"
		if args.lang and not args.lang2 then args.lang2 = args.lang .."-Latn" end
		if args.transl and not args.transl2 then args.transl2 = args.transl end
		if_auto_translit = true

	end
	local revid = frame:preprocess( "{{REVISIONID}}" )
	if revid == "" then
		if not args['display-messages'] or yesno(args['display-messages']) then
		displaying_messages = true end-- messages will be displayed only in preview mode
	end
	msg = UserMessages
	local line = {}

	local function set_italics(n)
		line[n].attr.style = line[n].attr.style .. "font-style: italic;"
		line[n].tone_sup = true -- single digits are assumed to be tone markers and will hence be superscripted
		if args['tone-superscripting'] and not yesno(args['tone-superscripting'])
			then line[n].tone_sup = false end
	end

	if args.glossing then -- the glossing= parameter sets the default glossing type
		local _gl = set_glossing_type(args.glossing)
		if _gl then conf.GlossingType = _gl end
	end
	--this looks for a list of glossing abbreviations on the page that transcludes the template:
	local _ablist_section = get_section(frame, 'list-of-glossing-abbreviations')
	if _ablist_section and _ablist_section ~= "" then
		local _a = mw.ustring.gsub(_ablist_section, '</?div [^\n]*>', '') -- strips off the div tags
		set_custom_glosses(_a)
	end
	--and this looks looks for a list of abbreviations set within the template:
	local _ablist = args.abbreviations
	if _ablist and _ablist ~= ""
		then set_custom_glosses(_ablist) end
	local _ablist = args.ablist
	if _ablist and _ablist ~= ""
		then set_custom_glosses(_ablist) end

	local _spacing = tonumber(args.spacing)
	if _spacing and _spacing <= 20
		then conf.style.WordDiv = conf.style.WordDiv .. 'margin-right: ' .. _spacing .. 'em;'
	else conf.style.WordDiv = conf.style.WordDiv .. conf.style.WordMargin
	end

	local offset, last_line = 0, 0
	for j,v in ipairs(args) do -- iterates over the unnamed parameters from the template
		last_line = last_line +1
		if is_empty(v)
			then offset = offset + 1
		else
		local i = j - offset
		line[i] = {}
		v = normalise(v)

		-- the following is part of a trial implementation of automatic transliteration:
		if if_auto_translit and v == "auto" and i > 1 then
			local source_line = line[i-1]
			local src_lang = source_line.lang
			if not src_lang then src_lang = args.lang end
			if src_lang then
					v = transliterate(source_line.whole, src_lang)
			else v = ""; msg:add("error", "No language specified for automatic transliteration")
			end
		end -- end of trial block

		line[i].whole = v
		line[i].length = mw.ustring.len(v)

		local _c = args["c" .. i]
		if _c and _c ~= "" then
			line.hasComments = true
			line[i].c = _c
		end

		---prepare style arguments----
		line[i].class = ""
		local _style = args["style" .. i]
		if not _style then _style = ""
		else _style = tidyCss(_style) end
		--line[i].attr holds the attributes for the <p> elements that enclose the words in line i
		line[i].attr = {style = conf.style.WordP .. _style}

		local _lang = args["lang" .. i]
		if _lang and #_lang > 1 then
			line[i].lang = _lang
		else _lang = args.lang
			if _lang and #_lang > 1 and i == 1 then -- if a lang= parameter is supplied, it's assumed to apply to line 1
				line[i].lang = _lang
			end
		end
		line[i].attr.lang = line[i].lang
		--the following emulates the behaviour of {{Bo-textonly}} (see Template talk:Fs interlinear#Tibetan):
		if template_name == 'Template:Fs interlinear' then
			if _lang == "bo" and i == 1 then
				line[1].class = line[1].class .. " uchen"
				line[1].attr.style = line[1].attr.style .. "font-size:1.25em; word-wrap:break-word;"
			end
		end
		--the following emulates the behaviour of {{Spell-nv}}:
		if template_name == 'Template:Interlinear' then
			if _lang == "nv" and i == 1 then
				line[1].attr.style = line[1].attr.style .. "font-family: Aboriginal Sans, DejaVu Sans, Calibri, Arial Unicode MS, sans-serif;"
			end
		end

		if yesno(args["italics" .. i]) then
			set_italics(i)
		end

		local _transl = args["transl" .. i]
		if _transl and #_transl > 1 then
			_transl = mw.ustring.lower(_transl)
			local _lookup = lang_data.translit_title_table[_transl]
			if _lookup then
				if _lang and _lookup[_lang] then
					_transl = _lookup[_lang]
				else _transl = _lookup.default
				end
				if _transl then
					line[i].attr.title = _transl
				end
			else msg:add("error", "Transliteration scheme '" .. _transl .. "' not recognised")
			end
		end

		local _glossing = args["glossing" .. i]
		if _glossing then
			line[i].glossing = set_glossing_type(_glossing)
			-- Do not treat default glossing settings as custom.
			if not ((i == 1 and not yesno(_glossing)) or (i == 2 and yesno(_glossing))) then
				line.HasCustomGlossing = true
			end
		end

		local _ipa = args['ipa' .. i]
		if yesno(_ipa) then
			line[i].class = "IPA"
		end

		local _class = args['class' .. i]
		if _class then
			line[i].class = line[i].class .. " " .. _class
		end

		if line[i].class == ""
			then line[i].class = nil end
		end -- ends the first if-statement in the loop
	end -- ends the FOR cycle

	local line_count = #line
	if line_count == 0 then
		msg:add("error", template_name .. ": no lines supplied.")
		return msg:print_errors()
	end

	if line_count > 1 then
		local _italics = args.italics
		local n = tonumber(_italics)
		if n and n > 0 then
			set_italics(n)
		elseif not (_italics and not yesno(_italics)) and not (args["italics1"] and not yesno(args["italics1"])) then
			set_italics(1) -- by default, the first line will get italicised, unless italics=no or italics1=no
		end
		-- the last unnamed parameter is assumed to be the free translation:
		free_translation = args[last_line]
		if not is_empty(free_translation) then
			line [line_count] = nil end --... and is thus excluded from interlinearising
	end

 -- If glossing isn't specified for any line, then it's chosen by default to occur
 -- in the second line, unless only a single line has been supplied, in which case
 -- the assumption is that it is the one containing grammatical glosses
	if yesno(args.glossing) == false then
		line.HasCustomGlossing = true
	end
	if not line.HasCustomGlossing then
		if line_count == 1 then
			line[1].glossing = conf.GlossingType
		elseif line[2] then
			line[2].glossing = conf.GlossingType
		end
	end
	set_global_glossing_settings{style = args['glossing-style'], underline = args.underline, small_caps = args['small-caps']}

 ---------------------
 -- Segment lines into words
 ---------------------
	for i,v in ipairs(line) do
		local ifglossing = false
		if line[i].glossing then
			ifglossing = true -- if true the parser will attempt to format gloss abbreviations in the current line
			glossing_type = line[i].glossing -- neccessarily a global variable
		end
		local wc, n = 1, 1
		line[i].words = {}
		while n <= line[i].length do
			buffer = ""
			n = parse(line[i], n, 0, ifglossing)+2
			line[i].words[wc] = buffer
			wc = wc + 1
		end
	end

	----Check for mismatches in number of words across lines----
	local number_of_words, mismatch_found = 0, false
	for i,v in ipairs(line) do -- find the maximum number of words in any line
		local wc = #line[i].words
		if wc ~= number_of_words then
			if i ~= 1 and wc ~= 0 then
				mismatch_found = true
			end
			if wc > number_of_words then
				number_of_words = wc
			end
		end
	end
	----Deal with mismatches---
	if mismatch_found then
		local error_text = "Mismatch in the number of words between lines: "
		for i,v in ipairs(line) do
			local wc = #line[i].words
			error_text = error_text .. wc .. " word(s) in line " .. i .. ", "
			if wc ~= number_of_words then
				for current_word = wc+1, number_of_words do
					line[i].words[current_word] = "&nbsp;"
				end
			end
		end
		if string.sub(error_text, -2) == ", "
			then error_text = string.sub(error_text, 1, #error_text - 2) .. " "
		end
		error_text = error_text .. help_link("mismatch")
		UserMessages:add("error", error_text)
	end

 ---------------------
 -- Build the HTML
 ---------------------
	---- If just a single line was supplied, format it as inline text
	if line_count == 1 then
		local span = mw.html.create('span')
		span:attr(line[1].attr)
		for wi = 1, number_of_words do
			local space
			if wi < number_of_words then space = " " else space = "" end
			span:wikitext(line[1].words[wi] .. space)
		end
		return tostring(span)
	end

	---- More than one line supplied, so we'll produce interlinear display
	local div = mw.html.create("div")
	div:addClass(conf.class.Interlinear)

	-- For stuff to be displayed in the left margin, like example numbering
	local number, indent = nil, nil
	if args.number and args.number ~= ""
		then number = args.number end
	if args.indent and args.indent ~=""
		then indent = args.indent end
	if indent or number then
		if not indent then indent = "4" end --default value
		div:css("margin-left", indent .. 'em')
		if number then
			div:tag("div")
				:css("position", "absolute")
				:css("left", "1em")
				:wikitext(args.number)
		end
	end

	if args.box and args.box ~= "" then
		div:css("background-color", "#f8f9fa")
			:css("border", "1px solid #eaecf0")
			:css("padding", "1em") end
	if args.top and args.top ~= "" then --lines to display above the interlinear block
		div:tag("div")
			:wikitext(args.top)
	end

	-- Producing the interlinear block
	for wi = 1, number_of_words do
		local div2 = div:tag("div")
					:attr("style", conf.style.WordDiv)
		for i,_ in ipairs (line) do
			if line[i].whole ~= "" then -- skipping empty lines
				local p = div2:tag("p")
				p:attr(line[i].attr)
				if line[i].class then
					p:addClass(line[i].class)
				end
				local _text = line[i].words[wi]
				if _text == "" or _text == " "
					then _text = "&nbsp;" end -- <p> elements without content mess up the interlinear display
				p:wikitext(_text)
			end
		end
	end

	--- If any "comments" have been specified, add them at the end of each line
	if line.hasComments then
		local divc = div:tag("div")
					:attr("style", conf.style.WordDiv)
		for i,_ in ipairs (line) do
			local p = divc:tag("p")
			p:attr("style", conf.style.WordP)
			if line[i].c then
				p:wikitext(line[i].c)
			else p:wikitext("&nbsp;")
			end
		end
	end

	--Add hidden lines containing the content of each line of interlinear text: this is for accessibility
	for i,v in ipairs(line) do
		local hidden_line = div:tag("p")
		hidden_line:attr("style", conf.style.HiddenText)
					:wikitext(v.whole)
	end

	-- Format the free translation
	local ft_line = div:tag("p")
	if free_translation and free_translation ~= "" then
		ft_line:attr("style", "clear: left;")
		ft_line:wikitext(free_translation)
	end
	if args.bottom and args.bottom ~= ""
		then local bottom = div:tag('p')
		bottom:css('margin-top', '0')
		bottom:wikitext(args.bottom)
	end
	ft_line:node(msg:print_errors()) -- for error messages

	local end_div = div:tag("div")
		end_div:attr("style", conf.style.EndDiv)
	div:newline()
	local temp_track = ""
	if last_line == 2
		then temp_track = "[[Category:Pages with interlinear glosses using two unnamed parameters]]"
	end
	if last_line > 3 and template_name ~= 'Template:Fs interlinear'
		then temp_track = "[[Category:Pages with interlinear glosses using more than three unnamed parameters]]"
	end
	return tostring(div) .. temp_track .. msg:print_warnings()
 end

 return p