Diff: Module:Convert

-- Convert a value from one unit of measurement to another.

-- Convert a value from one unit of measurement to another.

-- Example: {{convert|123|lb|kg}} --> 123 pounds (56 kg)

-- Example: {{convert|123|lb|kg}} --> 123 pounds (56 kg)

-- See [[:en:Template:Convert/Transwiki guide]] if copying to another wiki.

-- See [[:en:Template:Convert/Transwiki guide]] if copying to another wiki.

local MINUS = '−'  -- Unicode U+2212 MINUS SIGN (UTF-8: e2 88 92)

local MINUS = '−'  -- Unicode U+2212 MINUS SIGN (UTF-8: e2 88 92)

local abs = math.abs

local abs = math.abs

local floor = math.floor

local floor = math.floor

local format = string.format

local format = string.format

local log10 = math.log10

local log10 = math.log10

local ustring = mw.ustring

local ustring = mw.ustring

local ulen = ustring.len

local ulen = ustring.len

local usub = ustring.sub

local usub = ustring.sub

-- Configuration options to keep magic values in one location.

-- Configuration options to keep magic values in one location.

-- Conversion data and message text are defined in separate modules.

-- Conversion data and message text are defined in separate modules.

local config, maxsigfig

local config, maxsigfig

local numdot  -- must be '.' or ',' or a character which works in a regex

local numdot  -- must be '.' or ',' or a character which works in a regex

local numsep, numsep_remove, numsep_remove2

local numsep, numsep_remove, numsep_remove2

local data_code, all_units

local data_code, all_units

local text_code

local text_code

local varname        -- can be a code to use variable names that depend on value

local varname        -- can be a code to use variable names that depend on value

local from_en_table  -- to translate an output string of en digits to local language

local from_en_table  -- to translate an output string of en digits to local language

local to_en_table    -- to translate an input string of digits in local language to en

local to_en_table    -- to translate an input string of digits in local language to en

-- Use translation_table in convert/text to change the following.

-- Use translation_table in convert/text to change the following.

local en_default           -- true uses lang=en unless convert has lang=local or local digits

local en_default           -- true uses lang=en unless convert has lang=local or local digits

local group_method = 3     -- code for how many digits are in a group

local group_method = 3     -- code for how many digits are in a group

local per_word = 'per'     -- for units like "liters per kilometer"

local per_word = 'per'     -- for units like "liters per kilometer"

local plural_suffix = 's'  -- only other useful value is probably '' to disable plural unit names

local plural_suffix = 's'  -- only other useful value is probably '' to disable plural unit names

local omitsep              -- true to omit separator before local symbol/name

local omitsep              -- true to omit separator before local symbol/name

-- All units should be defined in the data module. However, to cater for quick changes

-- All units should be defined in the data module. However, to cater for quick changes

-- and experiments, any unknown unit is looked up in an extra data module, if it exists.

-- and experiments, any unknown unit is looked up in an extra data module, if it exists.

-- That module would be transcluded in only a small number of pages, so there should be

-- That module would be transcluded in only a small number of pages, so there should be

-- little server overhead from making changes, and changes should propagate quickly.

-- little server overhead from making changes, and changes should propagate quickly.

local extra_module  -- name of module with extra units

local extra_module  -- name of module with extra units

local extra_units   -- nil or table of extra units from extra_module

local extra_units   -- nil or table of extra units from extra_module

-- Some options in the invoking template can set variables used later in the module.

-- Some options in the invoking template can set variables used later in the module.

local currency_text  -- for a user-defined currency symbol: {{convert|12|$/ha|$=€}} (euro replaces dollar)

local currency_text  -- for a user-defined currency symbol: {{convert|12|$/ha|$=€}} (euro replaces dollar)

local function from_en(text)

local function from_en(text)

	-- Input is a string representing a number in en digits with '.' decimal mark,

	-- Input is a string representing a number in en digits with '.' decimal mark,

	-- without digit grouping (which is done just after calling this).

	-- without digit grouping (which is done just after calling this).

	-- Return the translation of the string with numdot and digits in local language.

	-- Return the translation of the string with numdot and digits in local language.

	if numdot ~= '.' then

	if numdot ~= '.' then

		text = text:gsub('%.', numdot)

		text = text:gsub('%.', numdot)

	end

	end

	if from_en_table then

	if from_en_table then

		text = text:gsub('%d', from_en_table)

		text = text:gsub('%d', from_en_table)

	end

	end

	return text

	return text

end

end

local function to_en(text)

local function to_en(text)

	-- Input is a string representing a number in the local language with

	-- Input is a string representing a number in the local language with

	-- an optional numdot decimal mark and numsep digit grouping.

	-- an optional numdot decimal mark and numsep digit grouping.

	-- Return the translation of the string with '.' mark and en digits,

	-- Return the translation of the string with '.' mark and en digits,

	-- and no separators (they have to be removed here to handle cases like

	-- and no separators (they have to be removed here to handle cases like

	-- numsep = '.' and numdot = ',' with input "1.234.567,8").

	-- numsep = '.' and numdot = ',' with input "1.234.567,8").

	if to_en_table then

	if to_en_table then

		text = ustring.gsub(text, '%d', to_en_table)

		text = ustring.gsub(text, '%d', to_en_table)

	end

	end

	if numsep_remove then

	if numsep_remove then

		text = text:gsub(numsep_remove, '')

		text = text:gsub(numsep_remove, '')

	end

	end

	if numsep_remove2 then

	if numsep_remove2 then

		text = text:gsub(numsep_remove2, '')

		text = text:gsub(numsep_remove2, '')

	end

	end

	if numdot ~= '.' then

	if numdot ~= '.' then

		text = text:gsub(numdot, '.')

		text = text:gsub(numdot, '.')

	end

	end

	return text

	return text

end

end

local function decimal_mark(text)

local function decimal_mark(text)

	-- Return ',' if text probably is using comma for decimal mark, or has no decimal mark.

	-- Return ',' if text probably is using comma for decimal mark, or has no decimal mark.

	-- Return '.' if text probably is using dot for decimal mark.

	-- Return '.' if text probably is using dot for decimal mark.

	-- Otherwise return nothing (decimal mark not known).

	-- Otherwise return nothing (decimal mark not known).

	if not text:find('[.,]') then return ',' end

	if not text:find('[.,]') then return ',' end

	text = text:gsub('^%-', ''):gsub('%+%d+/%d+$', ''):gsub('[Ee]%-?%d+$', '')

	text = text:gsub('^%-', ''):gsub('%+%d+/%d+$', ''):gsub('[Ee]%-?%d+$', '')

	local decimal =

	local decimal =

		text:match('^0?([.,])%d+$') or

		text:match('^0?([.,])%d+$') or

		text:match('%d([.,])%d?%d?$') or

		text:match('%d([.,])%d?%d?$') or

		text:match('%d([.,])%d%d%d%d+$')

		text:match('%d([.,])%d%d%d%d+$')

	if decimal then return decimal end

	if decimal then return decimal end

	if text:match('%.%d+%.') then return ',' end

	if text:match('%.%d+%.') then return ',' end

	if text:match('%,%d+,') then return '.' end

	if text:match('%,%d+,') then return '.' end

end

end

local add_warning, with_separator  -- forward declarations

local add_warning, with_separator  -- forward declarations

local function to_en_with_check(text, parms)

local function to_en_with_check(text, parms)

	-- Version of to_en() for a wiki using numdot = ',' and numsep = '.' to check

	-- Version of to_en() for a wiki using numdot = ',' and numsep = '.' to check

	-- text (an input number as a string) which might have been copied from enwiki.

	-- text (an input number as a string) which might have been copied from enwiki.

	-- For example, in '1.234' the '.' could be a decimal mark or a group separator.

	-- For example, in '1.234' the '.' could be a decimal mark or a group separator.

	-- From viwiki.

	-- From viwiki.

	if to_en_table then

	if to_en_table then

		text = ustring.gsub(text, '%d', to_en_table)

		text = ustring.gsub(text, '%d', to_en_table)

	end

	end

	if decimal_mark(text) == '.' then

	if decimal_mark(text) == '.' then

		local original = text

		local original = text

		text = text:gsub(',', '')  -- for example, interpret "1,234.5" as an enwiki value

		text = text:gsub(',', '')  -- for example, interpret "1,234.5" as an enwiki value

		if parms then

		if parms then

			add_warning(parms, 0, 'cvt_enwiki_num', original, with_separator({}, text))

			add_warning(parms, 0, 'cvt_enwiki_num', original, with_separator({}, text))

		end

		end

	else

	else

		if numsep_remove then

		if numsep_remove then

			text = text:gsub(numsep_remove, '')

			text = text:gsub(numsep_remove, '')

		end

		end

		if numsep_remove2 then

		if numsep_remove2 then

			text = text:gsub(numsep_remove2, '')

			text = text:gsub(numsep_remove2, '')

		end

		end

		if numdot ~= '.' then

		if numdot ~= '.' then

			text = text:gsub(numdot, '.')

			text = text:gsub(numdot, '.')

		end

		end

	end

	end

	return text

	return text

end

end

local function omit_separator(id)

local function omit_separator(id)

	-- Return true if there should be no separator before id (a unit symbol or name).

	-- Return true if there should be no separator before id (a unit symbol or name).

	-- For zhwiki, there should be no separator if id uses local characters.

	-- For zhwiki, there should be no separator if id uses local characters.

	-- The following kludge should be a sufficient test.

	-- The following kludge should be a sufficient test.

	if omitsep then

	if omitsep then

		if id:sub(1, 2) == '-{' then  -- for "-{...}-" content language variant

		if id:sub(1, 2) == '-{' then  -- for "-{...}-" content language variant

			return true

			return true

		end

		end

		if id:byte() > 127 then

		if id:byte() > 127 then

			local first = usub(id, 1, 1)

			local first = usub(id, 1, 1)

' and first ~= '°' and first ~= 'µ' then

' and first ~= '°' and first ~= 'µ' then

				return true

				return true

			end

			end

		end

		end

	end

	end

	return id:sub(1, 1) == '/'  -- no separator before units like "/ha"

	return id:sub(1, 1) == '/'  -- no separator before units like "/ha"

end

end

local spell_module  -- name of module that can spell numbers

local spell_module  -- name of module that can spell numbers

local speller       -- function from that module to handle spelling (set if needed)

local speller       -- function from that module to handle spelling (set if needed)

local wikidata_module, wikidata_data_module  -- names of Wikidata modules

local wikidata_module, wikidata_data_module  -- names of Wikidata modules

local wikidata_code, wikidata_data  -- exported tables from those modules (set if needed)

local wikidata_code, wikidata_data  -- exported tables from those modules (set if needed)

local function set_config(args)

local function set_config(args)

	-- Set configuration options from template #invoke or defaults.

	-- Set configuration options from template #invoke or defaults.

	config = args

	config = args

	maxsigfig = config.maxsigfig or 14  -- maximum number of significant figures

	maxsigfig = config.maxsigfig or 14  -- maximum number of significant figures

	local data_module, text_module

	local data_module, text_module

	local sandbox = config.sandbox and ('/' .. config.sandbox) or ''

	local sandbox = config.sandbox and ('/' .. config.sandbox) or ''

	data_module = "Module:Convert/data" .. sandbox

	data_module = "Module:Convert/data" .. sandbox

	text_module = "Module:Convert/text" .. sandbox

	text_module = "Module:Convert/text" .. sandbox

	extra_module = "Module:Convert/extra" .. sandbox

	extra_module = "Module:Convert/extra" .. sandbox

	wikidata_module = "Module:Convert/wikidata" .. sandbox

	wikidata_module = "Module:Convert/wikidata" .. sandbox

	wikidata_data_module = "Module:Convert/wikidata/data" .. sandbox

	wikidata_data_module = "Module:Convert/wikidata/data" .. sandbox

	spell_module = "Module:ConvertNumeric"

	spell_module = "Module:ConvertNumeric"

	data_code = mw.loadData(data_module)

	data_code = mw.loadData(data_module)

	text_code = mw.loadData(text_module)

	text_code = mw.loadData(text_module)

	all_units = data_code.all_units

	all_units = data_code.all_units

	local translation = text_code.translation_table

	local translation = text_code.translation_table

	if translation then

	if translation then

		numdot = translation.numdot

		numdot = translation.numdot

		numsep = translation.numsep

		numsep = translation.numsep

		if numdot == ',' and numsep == '.' then

		if numdot == ',' and numsep == '.' then

			if text_code.all_messages.cvt_enwiki_num then

			if text_code.all_messages.cvt_enwiki_num then

				to_en = to_en_with_check

				to_en = to_en_with_check

			end

			end

		end

		end

		if translation.group then

		if translation.group then

			group_method = translation.group

			group_method = translation.group

		end

		end

		if translation.per_word then

		if translation.per_word then

			per_word = translation.per_word

			per_word = translation.per_word

		end

		end

		if translation.plural_suffix then

		if translation.plural_suffix then

			plural_suffix = translation.plural_suffix

			plural_suffix = translation.plural_suffix

		end

		end

		varname = translation.varname

		varname = translation.varname

		from_en_table = translation.from_en

		from_en_table = translation.from_en

		local use_workaround = true

		local use_workaround = true

		if use_workaround then

		if use_workaround then

			-- 2013-07-05 workaround bug by making a copy of the required table.

			-- 2013-07-05 workaround bug by making a copy of the required table.

			-- mw.ustring.gsub fails with a table (to_en_table) as the replacement,

			-- mw.ustring.gsub fails with a table (to_en_table) as the replacement,

			-- if the table is accessed via mw.loadData.

			-- if the table is accessed via mw.loadData.

			local source = translation.to_en

			local source = translation.to_en

			if source then

			if source then

				to_en_table = {}

				to_en_table = {}

				for k, v in pairs(source) do

				for k, v in pairs(source) do

					to_en_table[k] = v

					to_en_table[k] = v

				end

				end

			end

			end

		else

		else

			to_en_table = translation.to_en

			to_en_table = translation.to_en

		end

		end

		if translation.lang == 'en default' then

		if translation.lang == 'en default' then

			en_default = true  -- for hiwiki

			en_default = true  -- for hiwiki

		end

		end

		omitsep = translation.omitsep  -- for zhwiki

		omitsep = translation.omitsep  -- for zhwiki

	end

	end

	numdot = config.numdot or numdot or '.'  -- decimal mark before fractional digits

	numdot = config.numdot or numdot or '.'  -- decimal mark before fractional digits

	numsep = config.numsep or numsep or ','  -- group separator for numbers

	numsep = config.numsep or numsep or ','  -- group separator for numbers

	-- numsep should be ',' or '.' or '' or ' ' or a Unicode character.

	-- numsep should be ',' or '.' or '' or ' ' or a Unicode character.

	-- numsep_remove must work in a regex to identify separators to be removed.

	-- numsep_remove must work in a regex to identify separators to be removed.

	if numsep ~= '' then

	if numsep ~= '' then

		numsep_remove = (numsep == '.') and '%.' or numsep

		numsep_remove = (numsep == '.') and '%.' or numsep

	end

	end

	if numsep ~= ',' and numdot ~= ',' then

	if numsep ~= ',' and numdot ~= ',' then

		numsep_remove2 = ','  -- so numbers copied from enwiki will work

		numsep_remove2 = ','  -- so numbers copied from enwiki will work

	end

	end

end

end

local function collection()

local function collection()

	-- Return a table to hold items.

	-- Return a table to hold items.

	return {

	return {

		n = 0,

		n = 0,

		add = function (self, item)

		add = function (self, item)

			self.n = self.n + 1

			self.n = self.n + 1

			self[self.n] = item

			self[self.n] = item

		end,

		end,

	}

	}

end

end

local function divide(numerator, denominator)

local function divide(numerator, denominator)

	-- Return integers quotient, remainder resulting from dividing the two

	-- Return integers quotient, remainder resulting from dividing the two

	-- given numbers, which should be unsigned integers.

	-- given numbers, which should be unsigned integers.

	local quotient, remainder = floor(numerator / denominator), numerator % denominator

	local quotient, remainder = floor(numerator / denominator), numerator % denominator

	if not (0 <= remainder and remainder < denominator) then

	if not (0 <= remainder and remainder < denominator) then

		-- Floating point limits may need this, as in {{convert|160.02|Ym|ydftin}}.

		-- Floating point limits may need this, as in {{convert|160.02|Ym|ydftin}}.

		remainder = 0

		remainder = 0

	end

	end

	return quotient, remainder

	return quotient, remainder

end

end

local function split(text, delimiter)

local function split(text, delimiter)

	-- Return a numbered table with fields from splitting text.

	-- Return a numbered table with fields from splitting text.

	-- The delimiter is used in a regex without escaping (for example, '.' would fail).

	-- The delimiter is used in a regex without escaping (for example, '.' would fail).

	-- Each field has any leading/trailing whitespace removed.

	-- Each field has any leading/trailing whitespace removed.

	local t = {}

	local t = {}

	text = text .. delimiter  -- to get last item

	text = text .. delimiter  -- to get last item

	for item in text:gmatch('%s*(.-)%s*' .. delimiter) do

	for item in text:gmatch('%s*(.-)%s*' .. delimiter) do

		table.insert(t, item)

		table.insert(t, item)

	end

	end

	return t

	return t

end

end

local function strip(text)

local function strip(text)

	-- If text is a string, return its content with no leading/trailing

	-- If text is a string, return its content with no leading/trailing

	-- whitespace. Otherwise return nil (a nil argument gives a nil result).

	-- whitespace. Otherwise return nil (a nil argument gives a nil result).

	if type(text) == 'string' then

	if type(text) == 'string' then

		return text:match("^%s*(.-)%s*$")

		return text:match("^%s*(.-)%s*$")

	end

	end

end

end

local function table_len(t)

local function table_len(t)

	-- Return length (<100) of a numbered table to replace #t which is

	-- Return length (<100) of a numbered table to replace #t which is

	-- documented to not work if t is accessed via mw.loadData().

	-- documented to not work if t is accessed via mw.loadData().

	for i = 1, 100 do

	for i = 1, 100 do

		if t[i] == nil then

		if t[i] == nil then

			return i - 1

			return i - 1

		end

		end

	end

	end

end

end

local function wanted_category(catkey, catsort, want_warning)

local function wanted_category(catkey, catsort, want_warning)

	-- Return message category if it is wanted in current namespace,

	-- Return message category if it is wanted in current namespace,

	-- otherwise return ''.

	-- otherwise return ''.

	local cat

	local cat

	local title = mw.title.getCurrentTitle()

	local title = mw.title.getCurrentTitle()

	if title then

	if title then

		local nsdefault = '0'  -- default namespace: '0' = article; '0,10' = article and template

		local nsdefault = '0'  -- default namespace: '0' = article; '0,10' = article and template

		local namespace = title.namespace

		local namespace = title.namespace

		for _, v in ipairs(split(config.nscat or nsdefault, ',')) do

		for _, v in ipairs(split(config.nscat or nsdefault, ',')) do

			if namespace == tonumber(v) then

			if namespace == tonumber(v) then

				cat = text_code.all_categories[want_warning and 'warning' or catkey]

				cat = text_code.all_categories[want_warning and 'warning' or catkey]

				if catsort and catsort ~= '' and cat:sub(-2) == ']]' then

				if catsort and catsort ~= '' and cat:sub(-2) == ']]' then

					cat = cat:sub(1, -3) .. '|' .. mw.text.nowiki(usub(catsort, 1, 20)) .. ']]'

					cat = cat:sub(1, -3) .. '|' .. mw.text.nowiki(usub(catsort, 1, 20)) .. ']]'

				end

				end

				break

				break

			end

			end

		end

		end

	end

	end

	return cat or ''

	return cat or ''

end

end

local function message(parms, mcode, is_warning)

local function message(parms, mcode, is_warning)

	-- Return wikitext for an error message, including category if specified

	-- Return wikitext for an error message, including category if specified

	-- for the message type.

	-- for the message type.

	-- mcode = numbered table specifying the message:

	-- mcode = numbered table specifying the message:

	--    mcode[1] = 'cvt_xxx' (string used as a key to get message info)

	--    mcode[1] = 'cvt_xxx' (string used as a key to get message info)

	--    mcode[2] = 'parm1' (string to replace '$1' if any in message)

	--    mcode[2] = 'parm1' (string to replace '$1' if any in message)

	--    mcode[3] = 'parm2' (string to replace '$2' if any in message)

	--    mcode[3] = 'parm2' (string to replace '$2' if any in message)

	--    mcode[4] = 'parm3' (string to replace '$3' if any in message)

	--    mcode[4] = 'parm3' (string to replace '$3' if any in message)

	local msg

	local msg

	if type(mcode) == 'table' then

	if type(mcode) == 'table' then

		if mcode[1] == 'cvt_no_output' then

		if mcode[1] == 'cvt_no_output' then

			-- Some errors should cause convert to output an empty string,

			-- Some errors should cause convert to output an empty string,

			-- for example, for an optional field in an infobox.

			-- for example, for an optional field in an infobox.

			return ''

			return ''

		end

		end

		msg = text_code.all_messages[mcode[1]]

		msg = text_code.all_messages[mcode[1]]

	end

	end

	parms.have_problem = true

	parms.have_problem = true

	local function subparm(fmt, ...)

	local function subparm(fmt, ...)

		local rep = {}

		local rep = {}

		for i, v in ipairs({...}) do

		for i, v in ipairs({...}) do

			rep['$' .. i] = v

			rep['$' .. i] = v

		end

		end

		return (fmt:gsub('$%d+', rep))

		return (fmt:gsub('$%d+', rep))

	end

	end

	if msg then

	if msg then

		local parts = {}

		local parts = {}

		local regex, replace = msg.regex, msg.replace

		local regex, replace = msg.regex, msg.replace

		for i = 1, 3 do

		for i = 1, 3 do

			local limit = 40

			local limit = 40

			local s = mcode[i + 1]

			local s = mcode[i + 1]

			if s then

			if s then

				if regex and replace then

				if regex and replace then

					s = s:gsub(regex, replace)

					s = s:gsub(regex, replace)

					limit = nil  -- allow long "should be" messages

					limit = nil  -- allow long "should be" messages

				end

				end

				-- Escape user input so it does not break the message.

				-- Escape user input so it does not break the message.

				-- To avoid tags (like {{convert|1<math>23</math>|m}}) breaking

				-- To avoid tags (like {{convert|1<math>23</math>|m}}) breaking

				-- the mouseover title, any strip marker starting with char(127) is

				-- the mouseover title, any strip marker starting with char(127) is

				-- replaced with '...' (text not needing i18n).

				-- replaced with '...' (text not needing i18n).

				local append

				local append

				local pos = s:find(string.char(127), 1, true)

				local pos = s:find(string.char(127), 1, true)

				if pos then

				if pos then

					append = '...'

					append = '...'

					s = s:sub(1, pos - 1)

					s = s:sub(1, pos - 1)

				end

				end

				if limit and ulen(s) > limit then

				if limit and ulen(s) > limit then

					s = usub(s, 1, limit)

					s = usub(s, 1, limit)

					append = '...'

					append = '...'

				end

				end

				s = mw.text.nowiki(s) .. (append or '')

				s = mw.text.nowiki(s) .. (append or '')

			else

			else

				s = '?'

				s = '?'

			end

			end

			parts['$' .. i] = s

			parts['$' .. i] = s

		end

		end

		local function ispreview()

		local function ispreview()

			-- Return true if a prominent message should be shown.

			-- Return true if a prominent message should be shown.

			if parms.test == 'preview' or parms.test == 'nopreview' then

			if parms.test == 'preview' or parms.test == 'nopreview' then

				-- For testing, can preview a real message or simulate a preview

				-- For testing, can preview a real message or simulate a preview

				-- when running automated tests.

				-- when running automated tests.

				return parms.test == 'preview'

				return parms.test == 'preview'

			end

			end

			local success, revid = pcall(function ()

			local success, revid = pcall(function ()

				return (parms.frame):preprocess('{{REVISIONID}}') end)

				return (parms.frame):preprocess('{{REVISIONID}}') end)

			return success and (revid == '')

			return success and (revid == '')

		end

		end

		local want_warning = is_warning and

		local want_warning = is_warning and

			not config.warnings and  -- show unobtrusive warnings if config.warnings not configured

			not config.warnings and  -- show unobtrusive warnings if config.warnings not configured

			not msg.nowarn           -- but use msg settings, not standard warning, if specified

			not msg.nowarn           -- but use msg settings, not standard warning, if specified

		local title = string.gsub(msg[1] or 'Missing message', '$%d+', parts)

		local title = string.gsub(msg[1] or 'Missing message', '$%d+', parts)

		local text = want_warning and '*' or msg[2] or 'Missing message'

		local text = want_warning and '*' or msg[2] or 'Missing message'

		local cat = wanted_category(msg[3], mcode[2], want_warning)

		local cat = wanted_category(msg[3], mcode[2], want_warning)

		local anchor = msg[4] or ''

		local anchor = msg[4] or ''

		local fmtkey = ispreview() and 'cvt_format_preview' or

		local fmtkey = ispreview() and 'cvt_format_preview' or

			(want_warning and 'cvt_format2' or msg.format or 'cvt_format')

			(want_warning and 'cvt_format2' or msg.format or 'cvt_format')

		local fmt = text_code.all_messages[fmtkey] or 'convert: bug'

		local fmt = text_code.all_messages[fmtkey] or 'convert: bug'

		return subparm(fmt, title:gsub('"', '"'), text, cat, anchor)

		return subparm(fmt, title:gsub('"', '"'), text, cat, anchor)

	end

	end

	return 'Convert internal error: unknown message'

	return 'Convert internal error: unknown message'

end

end

function add_warning(parms, level, key, text1, text2)  -- for forward declaration above

function add_warning(parms, level, key, text1, text2)  -- for forward declaration above

	-- If enabled, add a warning that will be displayed after the convert result.

	-- If enabled, add a warning that will be displayed after the convert result.

	-- A higher level is more verbose: more kinds of warnings are displayed.

	-- A higher level is more verbose: more kinds of warnings are displayed.

	-- To reduce output noise, only the first warning is displayed.

	-- To reduce output noise, only the first warning is displayed.

	if level <= (tonumber(config.warnings) or 1) then

	if level <= (tonumber(config.warnings) or 1) then

		if parms.warnings == nil then

		if parms.warnings == nil then

			parms.warnings = message(parms, { key, text1, text2 }, true)

			parms.warnings = message(parms, { key, text1, text2 }, true)

		end

		end

	end

	end

end

end

local function spell_number(parms, inout, number, numerator, denominator)

local function spell_number(parms, inout, number, numerator, denominator)

	-- Return result of spelling (number, numerator, denominator), or

	-- Return result of spelling (number, numerator, denominator), or

	-- return nil if spelling is not available or not supported for given text.

	-- return nil if spelling is not available or not supported for given text.

	-- Examples (each value must be a string or nil):

	-- Examples (each value must be a string or nil):

	--   number  numerator  denominator  output

	--   number  numerator  denominator  output

	--   ------  ---------  -----------  -------------------

	--   ------  ---------  -----------  -------------------

	--   "1.23"    nil        nil        one point two three

	--   "1.23"    nil        nil        one point two three

	--    "1"      "2"        "3"        one and two thirds

	--    "1"      "2"        "3"        one and two thirds

	--    nil      "2"        "3"        two thirds

	--    nil      "2"        "3"        two thirds

	if not speller then

	if not speller then

		local function get_speller(module)

		local function get_speller(module)

			return require(module).spell_number

			return require(module).spell_number

		end

		end

		local success

		local success

		success, speller = pcall(get_speller, spell_module)

		success, speller = pcall(get_speller, spell_module)

		if not success or type(speller) ~= 'function' then

		if not success or type(speller) ~= 'function' then

			add_warning(parms, 1, 'cvt_no_spell', 'spell')

			add_warning(parms, 1, 'cvt_no_spell', 'spell')

			return nil

			return nil

		end

		end

	end

	end

	local case

	local case

	if parms.spell_upper == inout then

	if parms.spell_upper == inout then

		case = true

		case = true

		parms.spell_upper = nil  -- only uppercase first word in a multiple unit

		parms.spell_upper = nil  -- only uppercase first word in a multiple unit

	end

	end

	local sp = not parms.opt_sp_us

	local sp = not parms.opt_sp_us

	local adj = parms.opt_adjectival

	local adj = parms.opt_adjectival

	return speller(number, numerator, denominator, case, sp, adj)

	return speller(number, numerator, denominator, case, sp, adj)

end

end

------------------------------------------------------------------------

------------------------------------------------------------------------

-- BEGIN: Code required only for built-in units.

-- BEGIN: Code required only for built-in units.

-- LATER: If need much more code, move to another module to simplify this module.

-- LATER: If need much more code, move to another module to simplify this module.

local function speed_of_sound(altitude)

local function speed_of_sound(altitude)

	-- This is for the Mach built-in unit of speed.

	-- This is for the Mach built-in unit of speed.

	-- Return speed of sound in metres per second at given altitude in feet.

	-- Return speed of sound in metres per second at given altitude in feet.

	-- If no altitude given, use default (zero altitude = sea level).

	-- If no altitude given, use default (zero altitude = sea level).

	-- Table gives speed of sound in miles per hour at various altitudes:

	-- Table gives speed of sound in miles per hour at various altitudes:

	--   altitude = -17,499 to 402,499 feet

	--   altitude = -17,499 to 402,499 feet

	-- mach_table[a + 4] = s where

	-- mach_table[a + 4] = s where

	--   a = (altitude / 5000) rounded to nearest integer (-3 to 80)

	--   a = (altitude / 5000) rounded to nearest integer (-3 to 80)

	--   s = speed of sound (mph) at that altitude

	--   s = speed of sound (mph) at that altitude

	-- LATER: Should calculate result from an interpolation between the next

	-- LATER: Should calculate result from an interpolation between the next

	-- lower and higher altitudes in table, rather than rounding to nearest.

	-- lower and higher altitudes in table, rather than rounding to nearest.

	-- From: http://www.aerospaceweb.org/question/atmosphere/q0112.shtml

	-- From: http://www.aerospaceweb.org/question/atmosphere/q0112.shtml

	local mach_table = {                                                       -- a =

	local mach_table = {                                                       -- a =

		799.5, 787.0, 774.2, 761.207051,                                       -- -3 to  0

		799.5, 787.0, 774.2, 761.207051,                                       -- -3 to  0

		748.0, 734.6, 721.0, 707.0, 692.8, 678.3, 663.5, 660.1, 660.1, 660.1,  --  1 to 10

		748.0, 734.6, 721.0, 707.0, 692.8, 678.3, 663.5, 660.1, 660.1, 660.1,  --  1 to 10

		660.1, 660.1, 660.1, 662.0, 664.3, 666.5, 668.9, 671.1, 673.4, 675.6,  -- 11 to 20

		660.1, 660.1, 660.1, 662.0, 664.3, 666.5, 668.9, 671.1, 673.4, 675.6,  -- 11 to 20

		677.9, 683.7, 689.9, 696.0, 702.1, 708.1, 714.0, 719.9, 725.8, 731.6,  -- 21 to 30

		677.9, 683.7, 689.9, 696.0, 702.1, 708.1, 714.0, 719.9, 725.8, 731.6,  -- 21 to 30

		737.3, 737.7, 737.7, 736.2, 730.5, 724.6, 718.8, 712.9, 707.0, 701.0,  -- 31 to 40

		737.3, 737.7, 737.7, 736.2, 730.5, 724.6, 718.8, 712.9, 707.0, 701.0,  -- 31 to 40

		695.0, 688.9, 682.8, 676.6, 670.4, 664.1, 657.8, 652.9, 648.3, 643.7,  -- 41 to 50

		695.0, 688.9, 682.8, 676.6, 670.4, 664.1, 657.8, 652.9, 648.3, 643.7,  -- 41 to 50

		639.1, 634.4, 629.6, 624.8, 620.0, 615.2, 613.2, 613.2, 613.2, 613.5,  -- 51 to 60

		639.1, 634.4, 629.6, 624.8, 620.0, 615.2, 613.2, 613.2, 613.2, 613.5,  -- 51 to 60

		614.4, 615.3, 616.7, 619.8, 623.4, 629.7, 635.0, 641.1, 650.6, 660.0,  -- 61 to 70

		614.4, 615.3, 616.7, 619.8, 623.4, 629.7, 635.0, 641.1, 650.6, 660.0,  -- 61 to 70

		672.5, 674.3, 676.1, 677.9, 679.7, 681.5, 683.3, 685.1, 686.8, 688.6,  -- 71 to 80

		672.5, 674.3, 676.1, 677.9, 679.7, 681.5, 683.3, 685.1, 686.8, 688.6,  -- 71 to 80

	}

	}

	altitude = altitude or 0

	altitude = altitude or 0

	local a = (altitude < 0) and -altitude or altitude

	local a = (altitude < 0) and -altitude or altitude

	a = floor(a / 5000 + 0.5)

	a = floor(a / 5000 + 0.5)

	if altitude < 0 then

	if altitude < 0 then

		a = -a

		a = -a

	end

	end

	if a < -3 then

	if a < -3 then

		a = -3

		a = -3

	elseif a > 80 then

	elseif a > 80 then

		a = 80

		a = 80

	end

	end

	return mach_table[a + 4] * 0.44704  -- mph converted to m/s

	return mach_table[a + 4] * 0.44704  -- mph converted to m/s

end

end

-- END: Code required only for built-in units.

-- END: Code required only for built-in units.

------------------------------------------------------------------------

------------------------------------------------------------------------

local function add_style(parms, class)

local function add_style(parms, class)

	-- Add selected template style to parms if not already present.

	-- Add selected template style to parms if not already present.

	parms.templatestyles = parms.templatestyles or {}

	parms.templatestyles = parms.templatestyles or {}

	if not parms.templatestyles[class] then

	if not parms.templatestyles[class] then

		parms.templatestyles[class] = parms.frame:extensionTag({

		parms.templatestyles[class] = parms.frame:extensionTag({

			name = 'templatestyles', args = { src = text_code.titles[class] }

			name = 'templatestyles', args = { src = text_code.titles[class] }

		})

		})

	end

	end

end

end

local function get_styles(parms)

local function get_styles(parms)

	-- Return string of required template styles, empty if none.

	-- Return string of required template styles, empty if none.

	if parms.templatestyles then

	if parms.templatestyles then

		local t = {}

		local t = {}

		for _, v in pairs(parms.templatestyles) do

		for _, v in pairs(parms.templatestyles) do

			table.insert(t, v)

			table.insert(t, v)

		end

		end

		return table.concat(t)

		return table.concat(t)

	end

	end

	return ''

	return ''

end

end

local function get_range(word)

local function get_range(word)

	-- Return a range (string or table) corresponding to word (like "to"),

	-- Return a range (string or table) corresponding to word (like "to"),

	-- or return nil if not a range word.

	-- or return nil if not a range word.

	local ranges = text_code.ranges

	local ranges = text_code.ranges

	return ranges.types[word] or ranges.types[ranges.aliases[word]]

	return ranges.types[word] or ranges.types[ranges.aliases[word]]

end

end

local function check_mismatch(unit1, unit2)

local function check_mismatch(unit1, unit2)

	-- If unit1 cannot be converted to unit2, return an error message table.

	-- If unit1 cannot be converted to unit2, return an error message table.

	-- This allows conversion between units of the same type, and between

	-- This allows conversion between units of the same type, and between

	-- Nm (normally torque) and ftlb (energy), as in gun-related articles.

	-- Nm (normally torque) and ftlb (energy), as in gun-related articles.

	-- This works because Nm is the base unit (scale = 1) for both the

	-- This works because Nm is the base unit (scale = 1) for both the

	-- primary type (torque), and the alternate type (energy, where Nm = J).

	-- primary type (torque), and the alternate type (energy, where Nm = J).

	-- A match occurs if the primary types are the same, or if unit1 matches

	-- A match occurs if the primary types are the same, or if unit1 matches

	-- the alternate type of unit2, and vice versa. That provides a whitelist

	-- the alternate type of unit2, and vice versa. That provides a whitelist

	-- of which conversions are permitted between normally incompatible types.

	-- of which conversions are permitted between normally incompatible types.

	if unit1.utype == unit2.utype or

	if unit1.utype == unit2.utype or

		(unit1.utype == unit2.alttype and unit1.alttype == unit2.utype) then

		(unit1.utype == unit2.alttype and unit1.alttype == unit2.utype) then

		return nil

		return nil

	end

	end

	return { 'cvt_mismatch', unit1.utype, unit2.utype }

	return { 'cvt_mismatch', unit1.utype, unit2.utype }

end

end

local function override_from(out_table, in_table, fields)

local function override_from(out_table, in_table, fields)

	-- Copy the specified fields from in_table to out_table, but do not

	-- Copy the specified fields from in_table to out_table, but do not

	-- copy nil fields (keep any corresponding field in out_table).

	-- copy nil fields (keep any corresponding field in out_table).

	for _, field in ipairs(fields) do

	for _, field in ipairs(fields) do

		if in_table[field] then

		if in_table[field] then

			out_table[field] = in_table[field]

			out_table[field] = in_table[field]

		end

		end

	end

	end

end

end

local function shallow_copy(t)

local function shallow_copy(t)

	-- Return a shallow copy of table t.

	-- Return a shallow copy of table t.

	-- Do not need the features and overhead of the Scribunto mw.clone().

	-- Do not need the features and overhead of the Scribunto mw.clone().

	local result = {}

	local result = {}

	for k, v in pairs(t) do

	for k, v in pairs(t) do

		result[k] = v

		result[k] = v

	end

	end

	return result

	return result

end

end

local unit_mt = {

local unit_mt = {

	-- Metatable to get missing values for a unit that does not accept SI prefixes.

	-- Metatable to get missing values for a unit that does not accept SI prefixes.

	-- Warning: The boolean value 'false' is returned for any missing field

	-- Warning: The boolean value 'false' is returned for any missing field

	-- so __index is not called twice for the same field in a given unit.

	-- so __index is not called twice for the same field in a given unit.

	__index = function (self, key)

	__index = function (self, key)

		local value

		local value

		if key == 'name1' or key == 'sym_us' then

		if key == 'name1' or key == 'sym_us' then

			value = self.symbol

			value = self.symbol

		elseif key == 'name2' then

		elseif key == 'name2' then

			value = self.name1 .. plural_suffix

			value = self.name1 .. plural_suffix

		elseif key == 'name1_us' then

		elseif key == 'name1_us' then

			value = self.name1

			value = self.name1

			if not rawget(self, 'name2_us') then

			if not rawget(self, 'name2_us') then

				-- If name1_us is 'foot', do not make name2_us by appending plural_suffix.

				-- If name1_us is 'foot', do not make name2_us by appending plural_suffix.

				self.name2_us = self.name2

				self.name2_us = self.name2

			end

			end

		elseif key == 'name2_us' then

		elseif key == 'name2_us' then

			local raw1_us = rawget(self, 'name1_us')

			local raw1_us = rawget(self, 'name1_us')

			if raw1_us then

			if raw1_us then

				value = raw1_us .. plural_suffix

				value = raw1_us .. plural_suffix

			else

			else

				value = self.name2

				value = self.name2

			end

			end

		elseif key == 'link' then

		elseif key == 'link' then

			value = self.name1

			value = self.name1

		else

		else

			value = false

			value = false

		end

		end

		rawset(self, key, value)

		rawset(self, key, value)

		return value

		return value

	end

	end

}

}

local function prefixed_name(unit, name, index)

local function prefixed_name(unit, name, index)

	-- Return unit name with SI prefix inserted at correct position.

	-- Return unit name with SI prefix inserted at correct position.

	-- index = 1 (name1), 2 (name2), 3 (name1_us), 4 (name2_us).

	-- index = 1 (name1), 2 (name2), 3 (name1_us), 4 (name2_us).

	-- The position is a byte (not character) index, so use Lua's sub().

	-- The position is a byte (not character) index, so use Lua's sub().

	local pos = rawget(unit, 'prefix_position')

	local pos = rawget(unit, 'prefix_position')

	if type(pos) == 'string' then

	if type(pos) == 'string' then

		pos = tonumber(split(pos, ',')[index])

		pos = tonumber(split(pos, ',')[index])

	end

	end

	if pos then

	if pos then

		return name:sub(1, pos - 1) .. unit.si_name .. name:sub(pos)

		return name:sub(1, pos - 1) .. unit.si_name .. name:sub(pos)

	end

	end

	return unit.si_name .. name

	return unit.si_name .. name

end

end

local unit_prefixed_mt = {

local unit_prefixed_mt = {

	-- Metatable to get missing values for a unit that accepts SI prefixes.

	-- Metatable to get missing values for a unit that accepts SI prefixes.

	-- Before use, fields si_name, si_prefix must be defined.

	-- Before use, fields si_name, si_prefix must be defined.

	-- The unit must define _symbol, _name1 and

	-- The unit must define _symbol, _name1 and

	-- may define _sym_us, _name1_us, _name2_us

	-- may define _sym_us, _name1_us, _name2_us

	-- (_sym_us, _name2_us may be defined for a language using sp=us

	-- (_sym_us, _name2_us may be defined for a language using sp=us

	-- to refer to a variant unrelated to U.S. units).

	-- to refer to a variant unrelated to U.S. units).

	__index = function (self, key)

	__index = function (self, key)

		local value

		local value

		if key == 'symbol' then

		if key == 'symbol' then

			value = self.si_prefix .. self._symbol

			value = self.si_prefix .. self._symbol

			if value == 'l' then value = 'L' end

			if value == 'l' then value = 'L' end

		elseif key == 'sym_us' then

		elseif key == 'sym_us' then

			value = rawget(self, '_sym_us')

			value = rawget(self, '_sym_us')

			if value then

			if value then

				value = self.si_prefix .. value

				value = self.si_prefix .. value

			else

			else

				value = self.symbol

				value = self.symbol

			end

			end

		elseif key == 'name1' then

		elseif key == 'name1' then

			value = prefixed_name(self, self._name1, 1)

			value = prefixed_name(self, self._name1, 1)

		elseif key == 'name2' then

		elseif key == 'name2' then

			value = rawget(self, '_name2')

			value = rawget(self, '_name2')

			if value then

			if value then

				value = prefixed_name(self, value, 2)

				value = prefixed_name(self, value, 2)

			else

			else

				value = self.name1 .. plural_suffix

				value = self.name1 .. plural_suffix

			end

			end

		elseif key == 'name1_us' then

		elseif key == 'name1_us' then

			value = rawget(self, '_name1_us')

			value = rawget(self, '_name1_us')

			if value then

			if value then

				value = prefixed_name(self, value, 3)

				value = prefixed_name(self, value, 3)

			else

			else

				value = self.name1

				value = self.name1

			end

			end

		elseif key == 'name2_us' then

		elseif key == 'name2_us' then

			value = rawget(self, '_name2_us')

			value = rawget(self, '_name2_us')

			if value then

			if value then

				value = prefixed_name(self, value, 4)

				value = prefixed_name(self, value, 4)

			elseif rawget(self, '_name1_us') then

			elseif rawget(self, '_name1_us') then

				value = self.name1_us .. plural_suffix

				value = self.name1_us .. plural_suffix

			else

			else

				value = self.name2

				value = self.name2

			end

			end

		elseif key == 'link' then

		elseif key == 'link' then

			value = self.name1

			value = self.name1

		else

		else

			value = false

			value = false

		end

		end

		rawset(self, key, value)

		rawset(self, key, value)

		return value

		return value

	end

	end

}

}

local unit_per_mt = {

local unit_per_mt = {

	-- Metatable to get values for a per unit of form "x/y".

	-- Metatable to get values for a per unit of form "x/y".

	-- This is never called to determine a unit name or link because per units

	-- This is never called to determine a unit name or link because per units

	-- are handled as a special case.

	-- are handled as a special case.

	-- Similarly, the default output is handled elsewhere, and for a symbol

	-- Similarly, the default output is handled elsewhere, and for a symbol

	-- this is only called from get_default() for default_exceptions.

	-- this is only called from get_default() for default_exceptions.

	__index = function (self, key)

	__index = function (self, key)

		local value

		local value

		if key == 'symbol' then

		if key == 'symbol' then

			local per = self.per

			local per = self.per

			local unit1, unit2 = per[1], per[2]

			local unit1, unit2 = per[1], per[2]

			if unit1 then

			if unit1 then

				value = unit1[key] .. '/' .. unit2[key]

				value = unit1[key] .. '/' .. unit2[key]

			else

			else

				value = '/' .. unit2[key]

				value = '/' .. unit2[key]

			end

			end

		elseif key == 'sym_us' then

		elseif key == 'sym_us' then

			value = self.symbol

			value = self.symbol

		elseif key == 'scale' then

		elseif key == 'scale' then

			local per = self.per

			local per = self.per

			local unit1, unit2 = per[1], per[2]

			local unit1, unit2 = per[1], per[2]

			value = (unit1 and unit1.scale or 1) * self.scalemultiplier / unit2.scale

			value = (unit1 and unit1.scale or 1) * self.scalemultiplier / unit2.scale

		else

		else

			value = false

			value = false

		end

		end

		rawset(self, key, value)

		rawset(self, key, value)

		return value

		return value

	end

	end

}

}

local function make_per(unitcode, unit_table, ulookup)

local function make_per(unitcode, unit_table, ulookup)

	-- Return true, t where t is a per unit with unit codes expanded to unit tables,

	-- Return true, t where t is a per unit with unit codes expanded to unit tables,

	-- or return false, t where t is an error message table.

	-- or return false, t where t is an error message table.

	local result = {

	local result = {

		unitcode = unitcode,

		unitcode = unitcode,

		utype = unit_table.utype,

		utype = unit_table.utype,

		per = {}

		per = {}

	}

	}

	override_from(result, unit_table, { 'invert', 'iscomplex', 'default', 'link', 'symbol', 'symlink' })

	override_from(result, unit_table, { 'invert', 'iscomplex', 'default', 'link', 'symbol', 'symlink' })

	result.symbol_raw = (result.symbol or false)  -- to distinguish between a defined exception and a metatable calculation

	result.symbol_raw = (result.symbol or false)  -- to distinguish between a defined exception and a metatable calculation

	local prefix

	local prefix

	for i, v in ipairs(unit_table.per) do

	for i, v in ipairs(unit_table.per) do

		if i == 1 and v == '' then

		if i == 1 and v == '' then

			-- First unit symbol can be empty; that gives a nil first unit table.

			-- First unit symbol can be empty; that gives a nil first unit table.

		elseif i == 1 and text_code.currency[v] then

		elseif i == 1 and text_code.currency[v] then

			prefix = currency_text or v

			prefix = currency_text or v

		else

		else

			local success, t = ulookup(v)

			local success, t = ulookup(v)

			if not success then return false, t end

			if not success then return false, t end

			result.per[i] = t

			result.per[i] = t

		end

		end

	end

	end

	local multiplier = unit_table.multiplier

	local multiplier = unit_table.multiplier

	if not result.utype then

	if not result.utype then

		-- Creating an automatic per unit.

		-- Creating an automatic per unit.

		local unit1 = result.per[1]

		local unit1 = result.per[1]

		local utype = (unit1 and unit1.utype or prefix or '') .. '/' .. result.per[2].utype

		local utype = (unit1 and unit1.utype or prefix or '') .. '/' .. result.per[2].utype

		local t = data_code.per_unit_fixups[utype]

		local t = data_code.per_unit_fixups[utype]

		if t then

		if t then

			if type(t) == 'table' then

			if type(t) == 'table' then

				utype = t.utype or utype

				utype = t.utype or utype

				result.link = result.link or t.link

				result.link = result.link or t.link

				multiplier = multiplier or t.multiplier

				multiplier = multiplier or t.multiplier

			else

			else

				utype = t

				utype = t

			end

			end

		end

		end

		result.utype = utype

		result.utype = utype

	end

	end

	result.scalemultiplier = multiplier or 1

	result.scalemultiplier = multiplier or 1

	result.vprefix = prefix or false  -- set to non-nil to avoid calling __index

	result.vprefix = prefix or false  -- set to non-nil to avoid calling __index

	return true, setmetatable(result, unit_per_mt)

	return true, setmetatable(result, unit_per_mt)

end

end

local function lookup(parms, unitcode, what, utable, fails, depth)

local function lookup(parms, unitcode, what, utable, fails, depth)

	-- Return true, t where t is a copy of the unit's converter table,

	-- Return true, t where t is a copy of the unit's converter table,

	-- or return false, t where t is an error message table.

	-- or return false, t where t is an error message table.

	-- Parameter 'what' determines whether combination units are accepted:

	-- Parameter 'what' determines whether combination units are accepted:

	--   'no_combination'  : single unit only

	--   'no_combination'  : single unit only

	--   'any_combination' : single unit or combination or output multiple

	--   'any_combination' : single unit or combination or output multiple

	--   'only_multiple'   : single unit or output multiple only

	--   'only_multiple'   : single unit or output multiple only

	-- Parameter unitcode is a symbol (like 'g'), with an optional SI prefix (like 'kg').

	-- Parameter unitcode is a symbol (like 'g'), with an optional SI prefix (like 'kg').

	-- If, for example, 'kg' is in this table, that entry is used;

	-- If, for example, 'kg' is in this table, that entry is used;

	-- otherwise the prefix ('k') is applied to the base unit ('g').

	-- otherwise the prefix ('k') is applied to the base unit ('g').

	-- If unitcode is a known combination code (and if allowed by what),

	-- If unitcode is a known combination code (and if allowed by what),

	-- a table of output multiple unit tables is included in the result.

	-- a table of output multiple unit tables is included in the result.

	-- For compatibility with the old template, an underscore in a unitcode is

	-- For compatibility with the old template, an underscore in a unitcode is

	-- replaced with a space so usage like {{convert|350|board_feet}} works.

	-- replaced with a space so usage like {{convert|350|board_feet}} works.

	-- Wikignomes may also put two spaces or " " in combinations, so

	-- Wikignomes may also put two spaces or " " in combinations, so

	-- replace underscore, " ", and multiple spaces with a single space.

	-- replace underscore, " ", and multiple spaces with a single space.

	utable = utable or parms.unittable or all_units

	utable = utable or parms.unittable or all_units

	fails = fails or {}

	fails = fails or {}

	depth = depth and depth + 1 or 1

	depth = depth and depth + 1 or 1

	if depth > 9 then

	if depth > 9 then

		-- There are ways to mistakenly define units which result in infinite

		-- There are ways to mistakenly define units which result in infinite

		-- recursion when lookup() is called. That gives a long delay and very

		-- recursion when lookup() is called. That gives a long delay and very

		-- confusing error messages, so the depth parameter is used as a guard.

		-- confusing error messages, so the depth parameter is used as a guard.

		return false, { 'cvt_lookup', unitcode }

		return false, { 'cvt_lookup', unitcode }

	end

	end

	if unitcode == nil or unitcode == '' then

	if unitcode == nil or unitcode == '' then

		return false, { 'cvt_no_unit' }

		return false, { 'cvt_no_unit' }

	end

	end

	unitcode = unitcode:gsub('_', ' '):gsub(' ', ' '):gsub('  +', ' ')

	unitcode = unitcode:gsub('_', ' '):gsub(' ', ' '):gsub('  +', ' ')

	local function call_make_per(t)

	local function call_make_per(t)

		return make_per(unitcode, t,

		return make_per(unitcode, t,

			function (ucode) return lookup(parms, ucode, 'no_combination', utable, fails, depth) end

			function (ucode) return lookup(parms, ucode, 'no_combination', utable, fails, depth) end

		)

		)

	end

	end

	local t = utable[unitcode]

	local t = utable[unitcode]

	if t then

	if t then

		if t.shouldbe then

		if t.shouldbe then

			return false, { 'cvt_should_be', t.shouldbe }

			return false, { 'cvt_should_be', t.shouldbe }

		end

		end

		if t.sp_us then

		if t.sp_us then

			parms.opt_sp_us = true

			parms.opt_sp_us = true

		end

		end

		local target = t.target  -- nil, or unitcode is an alias for this target

		local target = t.target  -- nil, or unitcode is an alias for this target

		if target then

		if target then

			local success, result = lookup(parms, target, what, utable, fails, depth)

			local success, result = lookup(parms, target, what, utable, fails, depth)

			if not success then return false, result end

			if not success then return false, result end

			override_from(result, t, { 'customary', 'default', 'link', 'symbol', 'symlink' })

			override_from(result, t, { 'customary', 'default', 'link', 'symbol', 'symlink' })

			local multiplier = t.multiplier

			local multiplier = t.multiplier

			if multiplier then

			if multiplier then

				result.multiplier = tostring(multiplier)

				result.multiplier = tostring(multiplier)

				result.scale = result.scale * multiplier

				result.scale = result.scale * multiplier

			end

			end

			return true, result

			return true, result

		end

		end

		if t.per then

		if t.per then

			return call_make_per(t)

			return call_make_per(t)

		end

		end

		local combo = t.combination  -- nil or a table of unitcodes

		local combo = t.combination  -- nil or a table of unitcodes

		if combo then

		if combo then

			local multiple = t.multiple

			local multiple = t.multiple

			if what == 'no_combination' or (what == 'only_multiple' and not multiple) then

			if what == 'no_combination' or (what == 'only_multiple' and not multiple) then

				return false, { 'cvt_bad_unit', unitcode }

				return false, { 'cvt_bad_unit', unitcode }

			end

			end

			-- Recursively create a combination table containing the

			-- Recursively create a combination table containing the

			-- converter table of each unitcode.

			-- converter table of each unitcode.

			local result = { utype = t.utype, multiple = multiple, combination = {} }

			local result = { utype = t.utype, multiple = multiple, combination = {} }

			local cvt = result.combination

			local cvt = result.combination

			for i, v in ipairs(combo) do

			for i, v in ipairs(combo) do

				local success, t = lookup(parms, v, multiple and 'no_combination' or 'only_multiple', utable, fails, depth)

				local success, t = lookup(parms, v, multiple and 'no_combination' or 'only_multiple', utable, fails, depth)

				if not success then return false, t end

				if not success then return false, t end

				cvt[i] = t

				cvt[i] = t

			end

			end

			return true, result

			return true, result

		end

		end

		local result = shallow_copy(t)

		local result = shallow_copy(t)

		result.unitcode = unitcode

		result.unitcode = unitcode

		if result.prefixes then

		if result.prefixes then

			result.si_name = ''

			result.si_name = ''

			result.si_prefix = ''

			result.si_prefix = ''

			return true, setmetatable(result, unit_prefixed_mt)

			return true, setmetatable(result, unit_prefixed_mt)

		end

		end

		return true, setmetatable(result, unit_mt)

		return true, setmetatable(result, unit_mt)

	end

	end

	local SIprefixes = text_code.SIprefixes

	local SIprefixes = text_code.SIprefixes

	for plen = SIprefixes[1] or 2, 1, -1 do

	for plen = SIprefixes[1] or 2, 1, -1 do

		-- Look for an SI prefix; should never occur with an alias.

		-- Look for an SI prefix; should never occur with an alias.

		-- Check for longer prefix first ('dam' is decametre).

		-- Check for longer prefix first ('dam' is decametre).

		-- SIprefixes[1] = prefix maximum #characters (as seen by mw.ustring.sub).

		-- SIprefixes[1] = prefix maximum #characters (as seen by mw.ustring.sub).

		local prefix = usub(unitcode, 1, plen)

		local prefix = usub(unitcode, 1, plen)

		local si = SIprefixes[prefix]

		local si = SIprefixes[prefix]

		if si then

		if si then

			local t = utable[usub(unitcode, plen+1)]

			local t = utable[usub(unitcode, plen+1)]

			if t and t.prefixes then

			if t and t.prefixes then

				local result = shallow_copy(t)

				local result = shallow_copy(t)

				result.unitcode = unitcode

				result.unitcode = unitcode

				result.si_name = parms.opt_sp_us and si.name_us or si.name

				result.si_name = parms.opt_sp_us and si.name_us or si.name

				result.si_prefix = si.prefix or prefix

				result.si_prefix = si.prefix or prefix

				result.scale = t.scale * 10 ^ (si.exponent * t.prefixes)

				result.scale = t.scale * 10 ^ (si.exponent * t.prefixes)

				return true, setmetatable(result, unit_prefixed_mt)

				return true, setmetatable(result, unit_prefixed_mt)

			end

			end

		end

		end

	end

	end

	-- Accept user-defined combinations like "acre+m2+ha" or "acre m2 ha" for output.

	-- Accept user-defined combinations like "acre+m2+ha" or "acre m2 ha" for output.

	-- If '+' is used, each unit code can include a space, and any error is fatal.

	-- If '+' is used, each unit code can include a space, and any error is fatal.

	-- If ' ' is used and if each space-separated word is a unit code, it is a combo,

	-- If ' ' is used and if each space-separated word is a unit code, it is a combo,

	-- but errors are not fatal so the unit code can be looked up as an extra unit.

	-- but errors are not fatal so the unit code can be looked up as an extra unit.

	local err_is_fatal

	local err_is_fatal

	local combo = collection()

	local combo = collection()

	if unitcode:find('+', 1, true) then

	if unitcode:find('+', 1, true) then

		err_is_fatal = true

		err_is_fatal = true

		for item in (unitcode .. '+'):gmatch('%s*(.-)%s*%+') do

		for item in (unitcode .. '+'):gmatch('%s*(.-)%s*%+') do

			if item ~= '' then

			if item ~= '' then

				combo:add(item)

				combo:add(item)

			end

			end

		end

		end

	elseif unitcode:find('%s') then

	elseif unitcode:find('%s') then

		for item in unitcode:gmatch('%S+') do

		for item in unitcode:gmatch('%S+') do

			combo:add(item)

			combo:add(item)

		end

		end

	end

	end

	if combo.n > 1 then

	if combo.n > 1 then

		local function lookup_combo()

		local function lookup_combo()

			if what == 'no_combination' or what == 'only_multiple' then

			if what == 'no_combination' or what == 'only_multiple' then

				return false, { 'cvt_bad_unit', unitcode }

				return false, { 'cvt_bad_unit', unitcode }

			end

			end

			local result = { combination = {} }

			local result = { combination = {} }

			local cvt = result.combination

			local cvt = result.combination

			for i, v in ipairs(combo) do

			for i, v in ipairs(combo) do

				local success, t = lookup(parms, v, 'only_multiple', utable, fails, depth)

				local success, t = lookup(parms, v, 'only_multiple', utable, fails, depth)

				if not success then return false, t end

				if not success then return false, t end

				if i == 1 then

				if i == 1 then

					result.utype = t.utype

					result.utype = t.utype

				else

				else

					local mismatch = check_mismatch(result, t)

					local mismatch = check_mismatch(result, t)

					if mismatch then

					if mismatch then

						return false, mismatch

						return false, mismatch

					end

					end

				end

				end

				cvt[i] = t

				cvt[i] = t

			end

			end

			return true, result

			return true, result

		end

		end

		local success, result = lookup_combo()

		local success, result = lookup_combo()

		if success or err_is_fatal then

		if success or err_is_fatal then

			return success, result

			return success, result

		end

		end

	end

	end

	-- Accept any unit with an engineering notation prefix like "e6cuft"

	-- Accept any unit with an engineering notation prefix like "e6cuft"

	-- (million cubic feet), but not chained prefixes like "e3e6cuft",

	-- (million cubic feet), but not chained prefixes like "e3e6cuft",

	-- and not if the unit is a combination or multiple,

	-- and not if the unit is a combination or multiple,

	-- and not if the unit has an offset or is a built-in.

	-- and not if the unit has an offset or is a built-in.

	-- Only en digits are accepted.

	-- Only en digits are accepted.

	local exponent, baseunit = unitcode:match('^e(%d+)(.*)')

	local exponent, baseunit = unitcode:match('^e(%d+)(.*)')

	if exponent then

	if exponent then

		local engscale = text_code.eng_scales[exponent]

		local engscale = text_code.eng_scales[exponent]

		if engscale then

		if engscale then

			local success, result = lookup(parms, baseunit, 'no_combination', utable, fails, depth)

			local success, result = lookup(parms, baseunit, 'no_combination', utable, fails, depth)

			if success and not (result.offset or result.builtin or result.engscale) then

			if success and not (result.offset or result.builtin or result.engscale) then

				result.unitcode = unitcode  -- 'e6cuft' not 'cuft'

				result.unitcode = unitcode  -- 'e6cuft' not 'cuft'

				result.defkey = unitcode  -- key to lookup default exception

				result.defkey = unitcode  -- key to lookup default exception

				result.engscale = engscale

				result.engscale = engscale

				result.scale = result.scale * 10 ^ tonumber(exponent)

				result.scale = result.scale * 10 ^ tonumber(exponent)

				return true, result

				return true, result

			end

			end

		end

		end

	end

	end

	-- Look for x/y; split on right-most slash to get scale correct (x/y/z is x/y per z).

	-- Look for x/y; split on right-most slash to get scale correct (x/y/z is x/y per z).

	local top, bottom = unitcode:match('^(.-)/([^/]+)$')

	local top, bottom = unitcode:match('^(.-)/([^/]+)$')

	if top and not unitcode:find('e%d') then

	if top and not unitcode:find('e%d') then

		-- If valid, create an automatic per unit for an "x/y" unit code.

		-- If valid, create an automatic per unit for an "x/y" unit code.

		-- The unitcode must not include extraneous spaces.

		-- The unitcode must not include extraneous spaces.

		-- Engineering notation (apart from at start and which has been stripped before here),

		-- Engineering notation (apart from at start and which has been stripped before here),

		-- is not supported so do not make a per unit if find text like 'e3' in unitcode.

		-- is not supported so do not make a per unit if find text like 'e3' in unitcode.

		local success, result = call_make_per({ per = {top, bottom} })

		local success, result = call_make_per({ per = {top, bottom} })

		if success then

		if success then

			return true, result

			return true, result

		end

		end

	end

	end

	if not parms.opt_ignore_error and not get_range(unitcode) then

	if not parms.opt_ignore_error and not get_range(unitcode) then

		-- Want the "what links here" list for the extra_module to show only cases

		-- Want the "what links here" list for the extra_module to show only cases

		-- where an extra unit is used, so do not require it if invoked from {{val}}

		-- where an extra unit is used, so do not require it if invoked from {{val}}

		-- or if looking up a range word which cannot be a unit.

		-- or if looking up a range word which cannot be a unit.

		if not extra_units then

		if not extra_units then

			local success, extra = pcall(function () return require(extra_module).extra_units end)

			local success, extra = pcall(function () return require(extra_module).extra_units end)

			if success and type(extra) == 'table' then

			if success and type(extra) == 'table' then

				extra_units = extra

				extra_units = extra

			end

			end

		end

		end

		if extra_units then

		if extra_units then

			-- A unit in one data table might refer to a unit in the other table, so

			-- A unit in one data table might refer to a unit in the other table, so

			-- switch between them, relying on fails or depth to terminate loops.

			-- switch between them, relying on fails or depth to terminate loops.

			if not fails[unitcode] then

			if not fails[unitcode] then

				fails[unitcode] = true

				fails[unitcode] = true

				local other = (utable == all_units) and extra_units or all_units

				local other = (utable == all_units) and extra_units or all_units

				local success, result = lookup(parms, unitcode, what, other, fails, depth)

				local success, result = lookup(parms, unitcode, what, other, fails, depth)

				if success then

				if success then

					return true, result

					return true, result

				end

				end

			end

			end

		end

		end

	end

	end

	if to_en_table then

	if to_en_table then

		-- At fawiki it is common to translate all digits so a unit like "km2" becomes "km۲".

		-- At fawiki it is common to translate all digits so a unit like "km2" becomes "km۲".

		local en_code = ustring.gsub(unitcode, '%d', to_en_table)

		local en_code = ustring.gsub(unitcode, '%d', to_en_table)

		if en_code ~= unitcode then

		if en_code ~= unitcode then

			return lookup(parms, en_code, what, utable, fails, depth)

			return lookup(parms, en_code, what, utable, fails, depth)

		end

		end

	end

	end

	return false, { 'cvt_unknown', unitcode }

	return false, { 'cvt_unknown', unitcode }

end

end

local function valid_number(num)

local function valid_number(num)

	-- Return true if num is a valid number.

	-- Return true if num is a valid number.

	-- In Scribunto (different from some standard Lua), when expressed as a string,

	-- In Scribunto (different from some standard Lua), when expressed as a string,

	-- overflow or other problems are indicated with text like "inf" or "nan"

	-- overflow or other problems are indicated with text like "inf" or "nan"

	-- which are regarded as invalid here (each contains "n").

	-- which are regarded as invalid here (each contains "n").

	if type(num) == 'number' and tostring(num):find('n', 1, true) == nil then

	if type(num) == 'number' and tostring(num):find('n', 1, true) == nil then

		return true

		return true

	end

	end

end

end

local function hyphenated(name, parts)

local function hyphenated(name, parts)

	-- Return a hyphenated form of given name (for adjectival usage).

	-- Return a hyphenated form of given name (for adjectival usage).

	-- The name may be linked and the target of the link must not be changed.

	-- The name may be linked and the target of the link must not be changed.

	-- Hypothetical examples:

	-- Hypothetical examples:

	--   [[long ton|ton]]         →  [[long ton|ton]]          (no change)

	--   [[long ton|ton]]         →  [[long ton|ton]]          (no change)

	--   [[tonne|long ton]]       →  [[tonne|long-ton]]

	--   [[tonne|long ton]]       →  [[tonne|long-ton]]

	--   [[metric ton|long ton]]  →  [[metric ton|long-ton]]

	--   [[metric ton|long ton]]  →  [[metric ton|long-ton]]

	--   [[long ton]]             →  [[long ton|long-ton]]

	--   [[long ton]]             →  [[long ton|long-ton]]

	-- Input can also have multiple links in a single name like:

	-- Input can also have multiple links in a single name like:

	--   [[United States customary units|U.S.]] [[US gallon|gallon]]

	--   [[United States customary units|U.S.]] [[US gallon|gallon]]

	--   [[mile]]s per [[United States customary units|U.S.]] [[quart]]

	--   [[mile]]s per [[United States customary units|U.S.]] [[quart]]

	--   [[long ton]]s per [[short ton]]

	--   [[long ton]]s per [[short ton]]

	-- Assume that links cannot be nested (never like "[[abc[[def]]ghi]]").

	-- Assume that links cannot be nested (never like "[[abc[[def]]ghi]]").

	-- This uses a simple and efficient procedure that works for most cases.

	-- This uses a simple and efficient procedure that works for most cases.

	-- Some units (if used) would require more, and can later think about

	-- Some units (if used) would require more, and can later think about

	-- adding a method to handle exceptions.

	-- adding a method to handle exceptions.

	-- The procedure is to replace each space with a hyphen, but

	-- The procedure is to replace each space with a hyphen, but

	-- not a space after ')' [for "(pre-1954 US) nautical mile"], and

	-- not a space after ')' [for "(pre-1954 US) nautical mile"], and

	-- not spaces immediately before '(' or in '(...)' [for cases like

	-- not spaces immediately before '(' or in '(...)' [for cases like

	-- "British thermal unit (ISO)" and "Calorie (International Steam Table)"].

	-- "British thermal unit (ISO)" and "Calorie (International Steam Table)"].

	if name:find(' ', 1, true) then

	if name:find(' ', 1, true) then

		if parts then

		if parts then

			local pos

			local pos

			if name:sub(1, 1) == '(' then

			if name:sub(1, 1) == '(' then

				pos = name:find(')', 1, true)

				pos = name:find(')', 1, true)

				if pos then

				if pos then

					return name:sub(1, pos+1) .. name:sub(pos+2):gsub(' ', '-')

					return name:sub(1, pos+1) .. name:sub(pos+2):gsub(' ', '-')

				end

				end

			elseif name:sub(-1) == ')' then

			elseif name:sub(-1) == ')' then

				pos = name:find('(', 1, true)

				pos = name:find('(', 1, true)

				if pos then

				if pos then

					return name:sub(1, pos-2):gsub(' ', '-') .. name:sub(pos-1)

					return name:sub(1, pos-2):gsub(' ', '-') .. name:sub(pos-1)

				end

				end

			end

			end

			return name:gsub(' ', '-')

			return name:gsub(' ', '-')

		end

		end

		parts = collection()

		parts = collection()

		for before, item, after in name:gmatch('([^[]*)(%[%[[^[]*%]%])([^[]*)') do

		for before, item, after in name:gmatch('([^[]*)(%[%[[^[]*%]%])([^[]*)') do

			if item:find(' ', 1, true) then

			if item:find(' ', 1, true) then

				local prefix

				local prefix

				local plen = item:find('|', 1, true)

				local plen = item:find('|', 1, true)

				if plen then

				if plen then

					prefix = item:sub(1, plen)

					prefix = item:sub(1, plen)

					item = item:sub(plen + 1, -3)

					item = item:sub(plen + 1, -3)

				else

				else

					prefix = item:sub(1, -3) .. '|'

					prefix = item:sub(1, -3) .. '|'

					item = item:sub(3, -3)

					item = item:sub(3, -3)

				end

				end

				item = prefix .. hyphenated(item, parts) .. ']]'

				item = prefix .. hyphenated(item, parts) .. ']]'

			end

			end

			parts:add(before:gsub(' ', '-') .. item .. after:gsub(' ', '-'))

			parts:add(before:gsub(' ', '-') .. item .. after:gsub(' ', '-'))

		end

		end

		if parts.n == 0 then

		if parts.n == 0 then

			-- No link like "[[...]]" was found in the original name.

			-- No link like "[[...]]" was found in the original name.

			parts:add(hyphenated(name, parts))

			parts:add(hyphenated(name, parts))

		end

		end

		return table.concat(parts)

		return table.concat(parts)

	end

	end

	return name

	return name

end

end

local function hyphenated_maybe(parms, want_name, sep, id, inout)

local function hyphenated_maybe(parms, want_name, sep, id, inout)

	-- Return s, f where

	-- Return s, f where

	--   s = id, possibly modified

	--   s = id, possibly modified

	--   f = true if hyphenated

	--   f = true if hyphenated

	-- Possible modifications: hyphenate; prepend '-'; append mid text.

	-- Possible modifications: hyphenate; prepend '-'; append mid text.

	if id == nil or id == '' then

	if id == nil or id == '' then

		return ''

		return ''

	end

	end

	local mid = (inout == (parms.opt_flip and 'out' or 'in')) and parms.mid or ''

	local mid = (inout == (parms.opt_flip and 'out' or 'in')) and parms.mid or ''

	if want_name then

	if want_name then

		if parms.opt_adjectival then

		if parms.opt_adjectival then

			return '-' .. hyphenated(id) .. mid, true

			return '-' .. hyphenated(id) .. mid, true

		end

		end

		if parms.opt_add_s and id:sub(-1) ~= 's' then

		if parms.opt_add_s and id:sub(-1) ~= 's' then

			id = id .. 's'  -- for nowiki

			id = id .. 's'  -- for nowiki

		end

		end

	end

	end

	return sep .. id .. mid

	return sep .. id .. mid

end

end

local function use_minus(text)

local function use_minus(text)

	-- Return text with Unicode minus instead of '-', if present.

	-- Return text with Unicode minus instead of '-', if present.

	if text:sub(1, 1) == '-' then

	if text:sub(1, 1) == '-' then

		return MINUS .. text:sub(2)

		return MINUS .. text:sub(2)

	end

	end

	return text

	return text

end

end

local function digit_groups(parms, text, method)

local function digit_groups(parms, text, method)

	-- Return a numbered table of groups of digits (left-to-right, in local language).

	-- Return a numbered table of groups of digits (left-to-right, in local language).

	-- Parameter method is a number or nil:

	-- Parameter method is a number or nil:

	--   3 for 3-digit grouping (default), or

	--   3 for 3-digit grouping (default), or

	--   2 for 3-then-2 grouping (only for digits before decimal mark).

	--   2 for 3-then-2 grouping (only for digits before decimal mark).

	local len_right

	local len_right

	local len_left = text:find('.', 1, true)

	local len_left = text:find('.', 1, true)

	if len_left then

	if len_left then

		len_right = #text - len_left

		len_right = #text - len_left

		len_left = len_left - 1

		len_left = len_left - 1

	else

	else

		len_left = #text

		len_left = #text

	end

	end

	local twos = method == 2 and len_left > 5

	local twos = method == 2 and len_left > 5

	local groups = collection()

	local groups = collection()

	local run = len_left

	local run = len_left

	local n

	local n

	if run < 4 or (run == 4 and parms.opt_comma5) then

	if run < 4 or (run == 4 and parms.opt_comma5) then

		if parms.opt_gaps then

		if parms.opt_gaps then

			n = run

			n = run

		else

		else

			n = #text

			n = #text

		end

		end

	elseif twos then

	elseif twos then

		n = run % 2 == 0 and 1 or 2

		n = run % 2 == 0 and 1 or 2

	else

	else

		n = run % 3 == 0 and 3 or run % 3

		n = run % 3 == 0 and 3 or run % 3

	end

	end

	while run > 0 do

	while run > 0 do

		groups:add(n)

		groups:add(n)

		run = run - n

		run = run - n

		n = (twos and run > 3) and 2 or 3

		n = (twos and run > 3) and 2 or 3

	end

	end

	if len_right then

	if len_right then

		if groups.n == 0 then

		if groups.n == 0 then

			groups:add(0)

			groups:add(0)

		end

		end

		if parms.opt_gaps and len_right > 3 then

		if parms.opt_gaps and len_right > 3 then

			local want4 = not parms.opt_gaps3  -- true gives no gap before trailing single digit

			local want4 = not parms.opt_gaps3  -- true gives no gap before trailing single digit

			local isfirst = true

			local isfirst = true

			run = len_right

			run = len_right

			while run > 0 do

			while run > 0 do

				n = (want4 and run == 4) and 4 or (run > 3 and 3 or run)

				n = (want4 and run == 4) and 4 or (run > 3 and 3 or run)

				if isfirst then

				if isfirst then

					isfirst = false

					isfirst = false

					groups[groups.n] = groups[groups.n] + 1 + n

					groups[groups.n] = groups[groups.n] + 1 + n

				else

				else

					groups:add(n)

					groups:add(n)

				end

				end

				run = run - n

				run = run - n

			end

			end

		else

		else

			groups[groups.n] = groups[groups.n] + 1 + len_right

			groups[groups.n] = groups[groups.n] + 1 + len_right

		end

		end

	end

	end

	local pos = 1

	local pos = 1

	for i, length in ipairs(groups) do

	for i, length in ipairs(groups) do

		groups[i] = from_en(text:sub(pos, pos + length - 1))

		groups[i] = from_en(text:sub(pos, pos + length - 1))

		pos = pos + length

		pos = pos + length

	end

	end

	return groups

	return groups

end

end

function with_separator(parms, text)  -- for forward declaration above

function with_separator(parms, text)  -- for forward declaration above

	-- Input text is a number in en digits with optional '.' decimal mark.

	-- Input text is a number in en digits with optional '.' decimal mark.

	-- Return an equivalent, formatted for display:

	-- Return an equivalent, formatted for display:

	--   with a custom decimal mark instead of '.', if wanted

	--   with a custom decimal mark instead of '.', if wanted

	--   with thousand separators inserted, if wanted

	--   with thousand separators inserted, if wanted

	--   digits in local language

	--   digits in local language

	-- The given text is like '123' or '123.' or '12345.6789'.

	-- The given text is like '123' or '123.' or '12345.6789'.

	-- The text has no sign (caller inserts that later, if necessary).

	-- The text has no sign (caller inserts that later, if necessary).

	-- When using gaps, they are inserted before and after the decimal mark.

	-- When using gaps, they are inserted before and after the decimal mark.

	-- Separators are inserted only before the decimal mark.

	-- Separators are inserted only before the decimal mark.

	-- A trailing dot (as in '123.') is removed because their use appears to

	-- A trailing dot (as in '123.') is removed because their use appears to

	-- be accidental, and such a number should be shown as '123' or '123.0'.

	-- be accidental, and such a number should be shown as '123' or '123.0'.

	-- It is useful for convert to suppress the dot so, for example, '4000.'

	-- It is useful for convert to suppress the dot so, for example, '4000.'

	-- is a simple way of indicating that all the digits are significant.

	-- is a simple way of indicating that all the digits are significant.

	if text:sub(-1) == '.' then

	if text:sub(-1) == '.' then

		text = text:sub(1, -2)

		text = text:sub(1, -2)

	end

	end

	if #text < 4 or parms.opt_nocomma or numsep == '' then

	if #text < 4 or parms.opt_nocomma or numsep == '' then

		return from_en(text)

		return from_en(text)

	end

	end

	local groups = digit_groups(parms, text, group_method)

	local groups = digit_groups(parms, text, group_method)

	if parms.opt_gaps then

	if parms.opt_gaps then

		if groups.n <= 1 then

		if groups.n <= 1 then

			return groups[1] or ''

			return groups[1] or ''

		end

		end

		local nowrap = '<span style="white-space: nowrap">'

		local nowrap = '<span style="white-space: nowrap">'

		local gap = '<span style="margin-left: 0.25em">'

		local gap = '<span style="margin-left: 0.25em">'

		local close = '</span>'

		local close = '</span>'

		return nowrap .. groups[1] .. gap .. table.concat(groups, close .. gap, 2, groups.n) .. close .. close

		return nowrap .. groups[1] .. gap .. table.concat(groups, close .. gap, 2, groups.n) .. close .. close

	end

	end

	return table.concat(groups, numsep)

	return table.concat(groups, numsep)

end

end

-- An input value like 1.23e12 is displayed using scientific notation (1.23×10¹²).

-- An input value like 1.23e12 is displayed using scientific notation (1.23×10¹²).

-- That also makes the output use scientific notation, except for small values.

-- That also makes the output use scientific notation, except for small values.

-- In addition, very small or very large output values use scientific notation.

-- In addition, very small or very large output values use scientific notation.

-- Use format(fmtpower, significand, '10', exponent) where each argument is a string.

-- Use format(fmtpower, significand, '10', exponent) where each argument is a string.

local fmtpower = '%s<span style="margin:0 .15em 0 .25em">×</span>%s<sup>%s</sup>'

local fmtpower = '%s<span style="margin:0 .15em 0 .25em">×</span>%s<sup>%s</sup>'

local function with_exponent(parms, show, exponent)

local function with_exponent(parms, show, exponent)

	-- Return wikitext to display the implied value in scientific notation.

	-- Return wikitext to display the implied value in scientific notation.

	-- Input uses en digits; output uses digits in local language.

	-- Input uses en digits; output uses digits in local language.

	return format(fmtpower, with_separator(parms, show), from_en('10'), use_minus(from_en(tostring(exponent))))

	return format(fmtpower, with_separator(parms, show), from_en('10'), use_minus(from_en(tostring(exponent))))

end

end

local function make_sigfig(value, sigfig)

local function make_sigfig(value, sigfig)

	-- Return show, exponent that are equivalent to the result of

	-- Return show, exponent that are equivalent to the result of

	-- converting the number 'value' (where value >= 0) to a string,

	-- converting the number 'value' (where value >= 0) to a string,

	-- rounded to 'sigfig' significant figures.

	-- rounded to 'sigfig' significant figures.

	-- The returned items are:

	-- The returned items are:

	--   show: a string of digits; no sign and no dot;

	--   show: a string of digits; no sign and no dot;

	--         there is an implied dot before show.

	--         there is an implied dot before show.

	--   exponent: a number (an integer) to shift the implied dot.

	--   exponent: a number (an integer) to shift the implied dot.

	-- Resulting value = tonumber('.' .. show) * 10^exponent.

	-- Resulting value = tonumber('.' .. show) * 10^exponent.

	-- Examples:

	-- Examples:

	--   make_sigfig(23.456, 3) returns '235', 2 (.235 * 10^2).

	--   make_sigfig(23.456, 3) returns '235', 2 (.235 * 10^2).

	--   make_sigfig(0.0023456, 3) returns '235', -2 (.235 * 10^-2).

	--   make_sigfig(0.0023456, 3) returns '235', -2 (.235 * 10^-2).

	--   make_sigfig(0, 3) returns '000', 1 (.000 * 10^1).

	--   make_sigfig(0, 3) returns '000', 1 (.000 * 10^1).

	if sigfig <= 0 then

	if sigfig <= 0 then

		sigfig = 1

		sigfig = 1

	elseif sigfig > maxsigfig then

	elseif sigfig > maxsigfig then

		sigfig = maxsigfig

		sigfig = maxsigfig

	end

	end

	if value == 0 then

	if value == 0 then

		return string.rep('0', sigfig), 1

		return string.rep('0', sigfig), 1

	end

	end

	local exp, fracpart = math.modf(log10(value))

	local exp, fracpart = math.modf(log10(value))

	if fracpart >= 0 then

	if fracpart >= 0 then

		fracpart = fracpart - 1

		fracpart = fracpart - 1

		exp = exp + 1

		exp = exp + 1

	end

	end

	local digits = format('%.0f', 10^(fracpart + sigfig))

	local digits = format('%.0f', 10^(fracpart + sigfig))

	if #digits > sigfig then

	if #digits > sigfig then

		-- Overflow (for sigfig=3: like 0.9999 rounding to "1000"; need "100").

		-- Overflow (for sigfig=3: like 0.9999 rounding to "1000"; need "100").

		digits = digits:sub(1, sigfig)

		digits = digits:sub(1, sigfig)

		exp = exp + 1

		exp = exp + 1

	end

	end

	assert(#digits == sigfig, 'Bug: rounded number has wrong length')

	assert(#digits == sigfig, 'Bug: rounded number has wrong length')

	return digits, exp

	return digits, exp

end

end

-- Fraction output format.

-- Fraction output format.

local fracfmt = {

local fracfmt = {

	{ -- Like {{frac}} (fraction slash).

	{ -- Like {{frac}} (fraction slash).

		'<span class="frac">{SIGN}<span class="num">{NUM}</span>&frasl;<span class="den">{DEN}</span></span>',  -- 1/2

		'<span class="frac">{SIGN}<span class="num">{NUM}</span>&frasl;<span class="den">{DEN}</span></span>',  -- 1/2

		'<span class="frac">{SIGN}{WHOLE}<span class="sr-only">+</span><span class="num">{NUM}</span>&frasl;<span class="den">{DEN}</span></span>',  -- 1+2/3

		'<span class="frac">{SIGN}{WHOLE}<span class="sr-only">+</span><span class="num">{NUM}</span>&frasl;<span class="den">{DEN}</span></span>',  -- 1+2/3

		style = 'frac',

		style = 'frac',

	},

	},

	{ -- Like {{sfrac}} (stacked fraction, that is, horizontal bar).

	{ -- Like {{sfrac}} (stacked fraction, that is, horizontal bar).

		'<span class="sfrac tion">{SIGN}<span class="num">{NUM}</span><span class="sr-only">/</span><span class="den">{DEN}</span></span>',  -- 1//2

		'<span class="sfrac tion">{SIGN}<span class="num">{NUM}</span><span class="sr-only">/</span><span class="den">{DEN}</span></span>',  -- 1//2

		'<span class="sfrac">{SIGN}{WHOLE}<span class="sr-only">+</span><span class="tion"><span class="num">{NUM}</span><span class="sr-only">/</span><span class="den">{DEN}</span></span></span>',  -- 1+2//3

		'<span class="sfrac">{SIGN}{WHOLE}<span class="sr-only">+</span><span class="tion"><span class="num">{NUM}</span><span class="sr-only">/</span><span class="den">{DEN}</span></span></span>',  -- 1+2//3

		style = 'sfrac',

		style = 'sfrac',

	},

	},

}

}

local function format_fraction(parms, inout, negative, wholestr, numstr, denstr, do_spell, style)

local function format_fraction(parms, inout, negative, wholestr, numstr, denstr, do_spell, style)

	-- Return wikitext for a fraction, possibly spelled.

	-- Return wikitext for a fraction, possibly spelled.

	-- Inputs use en digits and have no sign; output uses digits in local language.

	-- Inputs use en digits and have no sign; output uses digits in local language.

	local wikitext

	local wikitext

	if not style then

	if not style then

		style = parms.opt_fraction_horizontal and 2 or 1

		style = parms.opt_fraction_horizontal and 2 or 1

	end

	end

	if wholestr == '' then

	if wholestr == '' then

		wholestr = nil

		wholestr = nil

	end

	end

	local substitute = {

	local substitute = {

		SIGN = negative and MINUS or '',

		SIGN = negative and MINUS or '',

		WHOLE = wholestr and with_separator(parms, wholestr),

		WHOLE = wholestr and with_separator(parms, wholestr),

		NUM = from_en(numstr),

		NUM = from_en(numstr),

		DEN = from_en(denstr),

		DEN = from_en(denstr),

	}

	}

	wikitext = fracfmt[style][wholestr and 2 or 1]:gsub('{(%u+)}', substitute)

	wikitext = fracfmt[style][wholestr and 2 or 1]:gsub('{(%u+)}', substitute)

	if do_spell then

	if do_spell then

		if negative then

		if negative then

			if wholestr then

			if wholestr then

				wholestr = '-' .. wholestr

				wholestr = '-' .. wholestr

			else

			else

				numstr = '-' .. numstr

				numstr = '-' .. numstr

			end

			end

		end

		end

		local s = spell_number(parms, inout, wholestr, numstr, denstr)

		local s = spell_number(parms, inout, wholestr, numstr, denstr)

		if s then

		if s then

			return s

			return s

		end

		end

	end

	end

	add_style(parms, fracfmt[style].style)

	add_style(parms, fracfmt[style].style)

	return wikitext

	return wikitext

end

end

local function format_number(parms, show, exponent, isnegative)

local function format_number(parms, show, exponent, isnegative)

	-- Parameter show is a string or a table containing strings.

	-- Parameter show is a string or a table containing strings.

	-- Each string is a formatted number in en digits and optional '.' decimal mark.

	-- Each string is a formatted number in en digits and optional '.' decimal mark.

	-- A table represents a fraction: integer, numerator, denominator;

	-- A table represents a fraction: integer, numerator, denominator;

	-- if a table is given, exponent must be nil.

	-- if a table is given, exponent must be nil.

	-- Return t where t is a table with fields:

	-- Return t where t is a table with fields:

	--   show = wikitext formatted to display implied value

	--   show = wikitext formatted to display implied value

	--          (digits in local language)

	--          (digits in local language)

	--   is_scientific = true if show uses scientific notation

	--   is_scientific = true if show uses scientific notation

	--   clean = unformatted show (possibly adjusted and with inserted '.')

	--   clean = unformatted show (possibly adjusted and with inserted '.')

	--          (en digits)

	--          (en digits)

	--   sign = '' or MINUS

	--   sign = '' or MINUS

	--   exponent = exponent (possibly adjusted)

	--   exponent = exponent (possibly adjusted)

	-- The clean and exponent fields can be used to calculate the

	-- The clean and exponent fields can be used to calculate the

	-- rounded absolute value, if needed.

	-- rounded absolute value, if needed.

	--

	--

	-- The value implied by the arguments is found from:

	-- The value implied by the arguments is found from:

	--   exponent is nil; and

	--   exponent is nil; and

	--   show is a string of digits (no sign), with an optional dot;

	--   show is a string of digits (no sign), with an optional dot;

	--   show = '123.4' is value 123.4, '1234' is value 1234.0;

	--   show = '123.4' is value 123.4, '1234' is value 1234.0;

	-- or:

	-- or:

	--   exponent is an integer indicating where dot should be;

	--   exponent is an integer indicating where dot should be;

	--   show is a string of digits (no sign and no dot);

	--   show is a string of digits (no sign and no dot);

	--   there is an implied dot before show;

	--   there is an implied dot before show;

	--   show does not start with '0';

	--   show does not start with '0';

	--   show = '1234', exponent = 3 is value 0.1234*10^3 = 123.4.

	--   show = '1234', exponent = 3 is value 0.1234*10^3 = 123.4.

	--

	--

	-- The formatted result:

	-- The formatted result:

	-- * Is for an output value and is spelled if wanted and possible.

	-- * Is for an output value and is spelled if wanted and possible.

	-- * Includes a Unicode minus if isnegative and not spelled.

	-- * Includes a Unicode minus if isnegative and not spelled.

	-- * Uses a custom decimal mark, if wanted.

	-- * Uses a custom decimal mark, if wanted.

	-- * Has digits grouped where necessary, if wanted.

	-- * Has digits grouped where necessary, if wanted.

	-- * Uses scientific notation if requested, or for very small or large values

	-- * Uses scientific notation if requested, or for very small or large values

	--   (which forces result to not be spelled).

	--   (which forces result to not be spelled).

	-- * Has no more than maxsigfig significant digits

	-- * Has no more than maxsigfig significant digits

	--   (same as old template and {{#expr}}).

	--   (same as old template and {{#expr}}).

	local xhi, xlo  -- these control when scientific notation (exponent) is used

	local xhi, xlo  -- these control when scientific notation (exponent) is used

	if parms.opt_scientific then

	if parms.opt_scientific then

		xhi, xlo = 4, 2  -- default for output if input uses e-notation

		xhi, xlo = 4, 2  -- default for output if input uses e-notation

	elseif parms.opt_scientific_always then

	elseif parms.opt_scientific_always then

		xhi, xlo = 0, 0  -- always use scientific notation (experimental)

		xhi, xlo = 0, 0  -- always use scientific notation (experimental)

	else

	else

		xhi, xlo = 10, 4  -- default

		xhi, xlo = 10, 4  -- default

	end

	end

	local sign = isnegative and MINUS or ''

	local sign = isnegative and MINUS or ''

	local maxlen = maxsigfig

	local maxlen = maxsigfig

	local tfrac

	local tfrac

	if type(show) == 'table' then

	if type(show) == 'table' then

		tfrac = show

		tfrac = show

		show = tfrac.wholestr

		show = tfrac.wholestr

		assert(exponent == nil, 'Bug: exponent given with fraction')

		assert(exponent == nil, 'Bug: exponent given with fraction')

	end

	end

	if not tfrac and not exponent then

	if not tfrac and not exponent then

		local integer, dot, decimals = show:match('^(%d*)(%.?)(.*)')

		local integer, dot, decimals = show:match('^(%d*)(%.?)(.*)')

		if integer == '0' or integer == '' then

		if integer == '0' or integer == '' then

			local zeros, figs = decimals:match('^(0*)([^0]?.*)')

			local zeros, figs = decimals:match('^(0*)([^0]?.*)')

			if #figs == 0 then

			if #figs == 0 then

				if #zeros > maxlen then

				if #zeros > maxlen then

					show = '0.' .. zeros:sub(1, maxlen)

					show = '0.' .. zeros:sub(1, maxlen)

				end

				end

			elseif #zeros >= xlo then

			elseif #zeros >= xlo then

				show = figs

				show = figs

				exponent = -#zeros

				exponent = -#zeros

			elseif #figs > maxlen then

			elseif #figs > maxlen then

				show = '0.' .. zeros .. figs:sub(1, maxlen)

				show = '0.' .. zeros .. figs:sub(1, maxlen)

			end

			end

		elseif #integer >= xhi then

		elseif #integer >= xhi then

			show = integer .. decimals

			show = integer .. decimals

			exponent = #integer

			exponent = #integer

		else

		else

			maxlen = maxlen + #dot

			maxlen = maxlen + #dot

			if #show > maxlen then

			if #show > maxlen then

				show = show:sub(1, maxlen)

				show = show:sub(1, maxlen)

			end

			end

		end

		end

	end

	end

	if exponent then

	if exponent then

		local function zeros(n)

		local function zeros(n)

			return string.rep('0', n)

			return string.rep('0', n)

		end

		end

		if #show > maxlen then

		if #show > maxlen then

			show = show:sub(1, maxlen)

			show = show:sub(1, maxlen)

		end

		end

		if exponent > xhi or exponent <= -xlo or (exponent == xhi and show ~= '1' .. zeros(xhi - 1)) then

		if exponent > xhi or exponent <= -xlo or (exponent == xhi and show ~= '1' .. zeros(xhi - 1)) then

			-- When xhi, xlo = 10, 4 (the default), scientific notation is used if the

			-- When xhi, xlo = 10, 4 (the default), scientific notation is used if the

			-- rounded value satisfies: value >= 1e9 or value < 1e-4 (1e9 = 0.1e10),

			-- rounded value satisfies: value >= 1e9 or value < 1e-4 (1e9 = 0.1e10),

			-- except if show is '1000000000' (1e9), for example:

			-- except if show is '1000000000' (1e9), for example:

			-- {{convert|1000000000|m|m|sigfig=10}} → 1,000,000,000 metres (1,000,000,000 m)

			-- {{convert|1000000000|m|m|sigfig=10}} → 1,000,000,000 metres (1,000,000,000 m)

			local significand

			local significand

			if #show > 1 then

			if #show > 1 then

				significand = show:sub(1, 1) .. '.' .. show:sub(2)

				significand = show:sub(1, 1) .. '.' .. show:sub(2)

			else

			else

				significand = show

				significand = show

			end

			end

			return {

			return {

				clean = '.' .. show,

				clean = '.' .. show,

				exponent = exponent,

				exponent = exponent,

				sign = sign,

				sign = sign,

				show = sign .. with_exponent(parms, significand, exponent-1),

				show = sign .. with_exponent(parms, significand, exponent-1),

				is_scientific = true,

				is_scientific = true,

			}

			}

		end

		end

		if exponent >= #show then

		if exponent >= #show then

			show = show .. zeros(exponent - #show)  -- result has no dot

			show = show .. zeros(exponent - #show)  -- result has no dot

		elseif exponent <= 0 then

		elseif exponent <= 0 then

			show = '0.' .. zeros(-exponent) .. show

			show = '0.' .. zeros(-exponent) .. show

		else

		else

			show = show:sub(1, exponent) .. '.' .. show:sub(exponent+1)

			show = show:sub(1, exponent) .. '.' .. show:sub(exponent+1)

		end

		end

	end

	end

	local formatted_show

	local formatted_show

	if tfrac then

	if tfrac then

		show = tostring(tfrac.value)  -- to set clean in returned table

		show = tostring(tfrac.value)  -- to set clean in returned table

		formatted_show = format_fraction(parms, 'out', isnegative, tfrac.wholestr, tfrac.numstr, tfrac.denstr, parms.opt_spell_out)

		formatted_show = format_fraction(parms, 'out', isnegative, tfrac.wholestr, tfrac.numstr, tfrac.denstr, parms.opt_spell_out)

	else

	else

		if isnegative and show:match('^0.?0*$') then

		if isnegative and show:match('^0.?0*$') then

			sign = ''  -- don't show minus if result is negative but rounds to zero

			sign = ''  -- don't show minus if result is negative but rounds to zero

		end

		end

		formatted_show = sign .. with_separator(parms, show)

		formatted_show = sign .. with_separator(parms, show)

		if parms.opt_spell_out then

		if parms.opt_spell_out then

			formatted_show = spell_number(parms, 'out', sign .. show) or formatted_show

			formatted_show = spell_number(parms, 'out', sign .. show) or formatted_show

		end

		end

	end

	end

	return {

	return {

		clean = show,

		clean = show,

		sign = sign,

		sign = sign,

		show = formatted_show,

		show = formatted_show,

		is_scientific = false,  -- to avoid calling __index

		is_scientific = false,  -- to avoid calling __index

	}

	}

end

end

local function extract_fraction(parms, text, negative)

local function extract_fraction(parms, text, negative)

	-- If text represents a fraction, return

	-- If text represents a fraction, return

	--   value, altvalue, show, denominator

	--   value, altvalue, show, denominator

	-- where

	-- where

	--   value is a number (value of the fraction in argument text)

	--   value is a number (value of the fraction in argument text)

	--   altvalue is an alternate interpretation of any fraction for the hands

	--   altvalue is an alternate interpretation of any fraction for the hands

	--        unit where "12.1+3/4" means 12 hands 1.75 inches

	--        unit where "12.1+3/4" means 12 hands 1.75 inches

	--   show is a string (formatted text for display of an input value,

	--   show is a string (formatted text for display of an input value,

	--        and is spelled if wanted and possible)

	--        and is spelled if wanted and possible)

	--   denominator is value of the denominator in the fraction

	--   denominator is value of the denominator in the fraction

	-- Otherwise, return nil.

	-- Otherwise, return nil.

	-- Input uses en digits and '.' decimal mark (input has been translated).

	-- Input uses en digits and '.' decimal mark (input has been translated).

	-- Output uses digits in local language and local decimal mark, if any.

	-- Output uses digits in local language and local decimal mark, if any.

	------------------------------------------------------------------------

	------------------------------------------------------------------------

	-- Originally this function accepted x+y/z where x, y, z were any valid

	-- Originally this function accepted x+y/z where x, y, z were any valid

	-- numbers, possibly with a sign. For example '1.23e+2+1.2/2.4' = 123.5,

	-- numbers, possibly with a sign. For example '1.23e+2+1.2/2.4' = 123.5,

	-- and '2-3/8' = 1.625. However, such usages were found to be errors or

	-- and '2-3/8' = 1.625. However, such usages were found to be errors or

	-- misunderstandings, so since August 2014 the following restrictions apply:

	-- misunderstandings, so since August 2014 the following restrictions apply:

	--   x (if present) is an integer or has a single digit after decimal mark

	--   x (if present) is an integer or has a single digit after decimal mark

	--   y and z are unsigned integers

	--   y and z are unsigned integers

	--   e-notation is not accepted

	--   e-notation is not accepted

	-- The overall number can start with '+' or '-' (so '12+3/4' and '+12+3/4'

	-- The overall number can start with '+' or '-' (so '12+3/4' and '+12+3/4'

	-- and '-12-3/4' are valid).

	-- and '-12-3/4' are valid).

	-- Any leading negative sign is removed by the caller, so only inputs

	-- Any leading negative sign is removed by the caller, so only inputs

	-- like the following are accepted here (may have whitespace):

	-- like the following are accepted here (may have whitespace):

	--   negative = false       false        true (there was a leading '-')

	--   negative = false       false        true (there was a leading '-')

	--   text     = '2/3'       '+2/3'       '2/3'

	--   text     = '2/3'       '+2/3'       '2/3'

	--   text     = '1+2/3'     '+1+2/3'     '1-2/3'

	--   text     = '1+2/3'     '+1+2/3'     '1-2/3'

	--   text     = '12.3+1/2'  '+12.3+1/2'  '12.3-1/2'

	--   text     = '12.3+1/2'  '+12.3+1/2'  '12.3-1/2'

	-- Values like '12.3+1/2' are accepted, but are intended only for use

	-- Values like '12.3+1/2' are accepted, but are intended only for use

	-- with the hands unit (not worth adding code to enforce that).

	-- with the hands unit (not worth adding code to enforce that).

	------------------------------------------------------------------------

	------------------------------------------------------------------------

	local leading_plus, prefix, numstr, slashes, denstr =

	local leading_plus, prefix, numstr, slashes, denstr =

		text:match('^%s*(%+?)%s*(.-)%s*(%d+)%s*(/+)%s*(%d+)%s*$')

		text:match('^%s*(%+?)%s*(.-)%s*(%d+)%s*(/+)%s*(%d+)%s*$')

	if not leading_plus then

	if not leading_plus then

		-- Accept a single U+2044 fraction slash because that may be pasted.

		-- Accept a single U+2044 fraction slash because that may be pasted.

		leading_plus, prefix, numstr, denstr =

		leading_plus, prefix, numstr, denstr =

			text:match('^%s*(%+?)%s*(.-)%s*(%d+)%s*⁄%s*(%d+)%s*$')

			text:match('^%s*(%+?)%s*(.-)%s*(%d+)%s*⁄%s*(%d+)%s*$')

		slashes = '/'

		slashes = '/'

	end

	end

	local numerator = tonumber(numstr)

	local numerator = tonumber(numstr)

	local denominator = tonumber(denstr)

	local denominator = tonumber(denstr)

	if numerator == nil or denominator == nil or (negative and leading_plus ~= '') then

	if numerator == nil or denominator == nil or (negative and leading_plus ~= '') then

		return nil

		return nil

	end

	end

	local whole, wholestr

	local whole, wholestr

	if prefix == '' then

	if prefix == '' then

		wholestr = ''

		wholestr = ''

		whole = 0

		whole = 0

	else

	else

		-- Any prefix must be like '12+' or '12-' (whole number and fraction sign);

		-- Any prefix must be like '12+' or '12-' (whole number and fraction sign);

		-- '12.3+' and '12.3-' are also accepted (single digit after decimal point)

		-- '12.3+' and '12.3-' are also accepted (single digit after decimal point)

		-- because '12.3+1/2 hands' is valid (12 hands 3½ inches).

		-- because '12.3+1/2 hands' is valid (12 hands 3½ inches).

		local num1, num2, frac_sign = prefix:match('^(%d+)(%.?%d?)%s*([+%-])$')

		local num1, num2, frac_sign = prefix:match('^(%d+)(%.?%d?)%s*([+%-])$')

		if num1 == nil then return nil end

		if num1 == nil then return nil end

		if num2 == '' then  -- num2 must be '' or like '.1' but not '.' or '.12'

		if num2 == '' then  -- num2 must be '' or like '.1' but not '.' or '.12'

			wholestr = num1

			wholestr = num1

		else

		else

			if #num2 ~= 2 then return nil end

			if #num2 ~= 2 then return nil end

			wholestr = num1 .. num2

			wholestr = num1 .. num2

		end

		end

		if frac_sign ~= (negative and '-' or '+') then return nil end

		if frac_sign ~= (negative and '-' or '+') then return nil end

		whole = tonumber(wholestr)

		whole = tonumber(wholestr)

		if whole == nil then return nil end

		if whole == nil then return nil end

	end

	end

	local value = whole + numerator / denominator

	local value = whole + numerator / denominator

	if not valid_number(value) then return nil end

	if not valid_number(value) then return nil end

	local altvalue = whole + numerator / (denominator * 10)

	local altvalue = whole + numerator / (denominator * 10)

	local style = #slashes  -- kludge: 1 or 2 slashes can be used to select style

	local style = #slashes  -- kludge: 1 or 2 slashes can be used to select style

	if style > 2 then style = 2 end

	if style > 2 then style = 2 end

	local wikitext = format_fraction(parms, 'in', negative, leading_plus .. wholestr, numstr, denstr, parms.opt_spell_in, style)

	local wikitext = format_fraction(parms, 'in', negative, leading_plus .. wholestr, numstr, denstr, parms.opt_spell_in, style)

	return value, altvalue, wikitext, denominator

	return value, altvalue, wikitext, denominator

end

end

local function extract_number(parms, text, another, no_fraction)

local function extract_number(parms, text, another, no_fraction)

	-- Return true, info if can extract a number from text,

	-- Return true, info if can extract a number from text,

	-- where info is a table with the result,

	-- where info is a table with the result,

	-- or return false, t where t is an error message table.

	-- or return false, t where t is an error message table.

	-- Input can use en digits or digits in local language and can

	-- Input can use en digits or digits in local language and can

	-- have references at the end. Accepting references is intended

	-- have references at the end. Accepting references is intended

	-- for use in infoboxes with a field for a value passed to convert.

	-- for use in infoboxes with a field for a value passed to convert.

	-- Parameter another = true if the expected value is not the first.

	-- Parameter another = true if the expected value is not the first.

	-- Before processing, the input text is cleaned:

	-- Before processing, the input text is cleaned:

	-- * Any thousand separators (valid or not) are removed.

	-- * Any thousand separators (valid or not) are removed.

	-- * Any sign is replaced with '-' (if negative) or '' (otherwise).

	-- * Any sign is replaced with '-' (if negative) or '' (otherwise).

	--   That replaces Unicode minus with '-'.

	--   That replaces Unicode minus with '-'.

	-- If successful, the returned info table contains named fields:

	-- If successful, the returned info table contains named fields:

	--   value    = a valid number

	--   value    = a valid number

	--   altvalue = a valid number, usually same as value but different

	--   altvalue = a valid number, usually same as value but different

	--              if fraction used (for hands unit)

	--              if fraction used (for hands unit)

	--   singular = true if value is 1 or -1 (to use singular form of units)

	--   singular = true if value is 1 or -1 (to use singular form of units)

	--   clean    = cleaned text with any separators and sign removed

	--   clean    = cleaned text with any separators and sign removed

	--              (en digits and '.' decimal mark)

	--              (en digits and '.' decimal mark)

	--   show     = text formatted for output, possibly with ref strip markers

	--   show     = text formatted for output, possibly with ref strip markers

	--              (digits in local language and custom decimal mark)

	--              (digits in local language and custom decimal mark)

	-- The resulting show:

	-- The resulting show:

	-- * Is for an input value and is spelled if wanted and possible.

	-- * Is for an input value and is spelled if wanted and possible.

	-- * Has a rounded value, if wanted.

	-- * Has a rounded value, if wanted.

	-- * Has digits grouped where necessary, if wanted.

	-- * Has digits grouped where necessary, if wanted.

	-- * If negative, a Unicode minus is used; otherwise the sign is

	-- * If negative, a Unicode minus is used; otherwise the sign is

	--   '+' (if the input text used '+'), or is '' (if no sign in input).

	--   '+' (if the input text used '+'), or is '' (if no sign in input).

	text = strip(text or '')

	text = strip(text or '')

	local reference

	local reference

	local pos = text:find('\127', 1, true)

	local pos = text:find('\127', 1, true)

	if pos then

	if pos then

		local before = text:sub(1, pos - 1)

		local before = text:sub(1, pos - 1)

		local remainder = text:sub(pos)

		local remainder = text:sub(pos)

		local refs = {}

		local refs = {}

		while #remainder > 0 do

		while #remainder > 0 do

			local ref, spaces

			local ref, spaces

			ref, spaces, remainder = remainder:match('^(\127[^\127]*UNIQ[^\127]*%-ref[^\127]*\127)(%s*)(.*)')

			ref, spaces, remainder = remainder:match('^(\127[^\127]*UNIQ[^\127]*%-ref[^\127]*\127)(%s*)(.*)')

			if ref then

			if ref then

				table.insert(refs, ref)

				table.insert(refs, ref)

			else

			else

				refs = {}

				refs = {}

				break

				break

			end

			end

		end

		end

		if #refs > 0 then

		if #refs > 0 then

			text = strip(before)

			text = strip(before)

			reference = table.concat(refs)

			reference = table.concat(refs)

		end

		end

	end

	end

	local clean = to_en(text, parms)

	local clean = to_en(text, parms)

	if clean == '' then

	if clean == '' then

		return false, { another and 'cvt_no_num2' or 'cvt_no_num' }

		return false, { another and 'cvt_no_num2' or 'cvt_no_num' }

	end

	end

	local isnegative, propersign = false, ''  -- most common case

	local isnegative, propersign = false, ''  -- most common case

	local singular, show, denominator

	local singular, show, denominator

	local value = tonumber(clean)

	local value = tonumber(clean)

	local altvalue

	local altvalue

	if value then

	if value then

		local sign = clean:sub(1, 1)

		local sign = clean:sub(1, 1)

		if sign == '+' or sign == '-' then

		if sign == '+' or sign == '-' then

			propersign = (sign == '+') and '+' or MINUS

			propersign = (sign == '+') and '+' or MINUS

			clean = clean:sub(2)

			clean = clean:sub(2)

		end

		end

		if value < 0 then

		if value < 0 then

			isnegative = true

			isnegative = true

			value = -value

			value = -value

		end

		end

	else

	else

		local valstr

		local valstr

		for _, prefix in ipairs({ '-', MINUS, '−' }) do

		for _, prefix in ipairs({ '-', MINUS, '−' }) do

			-- Including '-' sets isnegative in case input is a fraction like '-2-3/4'.

			-- Including '-' sets isnegative in case input is a fraction like '-2-3/4'.

			local plen = #prefix

			local plen = #prefix

			if clean:sub(1, plen) == prefix then

			if clean:sub(1, plen) == prefix then

				valstr = clean:sub(plen + 1)

				valstr = clean:sub(plen + 1)

				if valstr:match('^%s') then  -- "- 1" is invalid but "-1 - 1/2" is ok

				if valstr:match('^%s') then  -- "- 1" is invalid but "-1 - 1/2" is ok

					return false, { 'cvt_bad_num', text }

					return false, { 'cvt_bad_num', text }

				end

				end

				break

				break

			end

			end

		end

		end

		if valstr then

		if valstr then

			isnegative = true

			isnegative = true

			propersign = MINUS

			propersign = MINUS

			clean = valstr

			clean = valstr

			value = tonumber(clean)

			value = tonumber(clean)

		end

		end

		if value == nil then

		if value == nil then

			if not no_fraction then

			if not no_fraction then

				value, altvalue, show, denominator = extract_fraction(parms, clean, isnegative)

				value, altvalue, show, denominator = extract_fraction(parms, clean, isnegative)

			end

			end

			if value == nil then

			if value == nil then

				return false, { 'cvt_bad_num', text }

				return false, { 'cvt_bad_num', text }

			end

			end

			if value <= 1 then

			if value <= 1 then

				singular = true  -- for example, "½ mile" or "one half mile" (singular unit)

				singular = true  -- for example, "½ mile" or "one half mile" (singular unit)

			end

			end

		end

		end

	end

	end

	if not valid_number(value) then  -- for example, "1e310" may overflow

	if not valid_number(value) then  -- for example, "1e310" may overflow

		return false, { 'cvt_invalid_num' }

		return false, { 'cvt_invalid_num' }

	end

	end

	if show == nil then

	if show == nil then

		-- clean is a non-empty string with no spaces, and does not represent a fraction,

		-- clean is a non-empty string with no spaces, and does not represent a fraction,

		-- and value = tonumber(clean) is a number >= 0.

		-- and value = tonumber(clean) is a number >= 0.

		-- If the input uses e-notation, show will be displayed using a power of ten, but

		-- If the input uses e-notation, show will be displayed using a power of ten, but

		-- we use the number as given so it might not be normalized scientific notation.

		-- we use the number as given so it might not be normalized scientific notation.

		-- The input value is spelled if specified so any e-notation is ignored;

		-- The input value is spelled if specified so any e-notation is ignored;

		-- that allows input like 2e6 to be spelled as "two million" which works

		-- that allows input like 2e6 to be spelled as "two million" which works

		-- because the spell module converts '2e6' to '2000000' before spelling.

		-- because the spell module converts '2e6' to '2000000' before spelling.

		local function rounded(value, default, exponent)

		local function rounded(value, default, exponent)

			local precision = parms.opt_ri

			local precision = parms.opt_ri

			if precision then

			if precision then

				local fmt = '%.' .. format('%d', precision) .. 'f'

				local fmt = '%.' .. format('%d', precision) .. 'f'

				local result = fmt:format(tonumber(value) + 2e-14)  -- fudge for some common cases of bad rounding

				local result = fmt:format(tonumber(value) + 2e-14)  -- fudge for some common cases of bad rounding

				if not exponent then

				if not exponent then

					singular = (tonumber(result) == 1)

					singular = (tonumber(result) == 1)

				end

				end

				return result

				return result

			end

			end

			return default

			return default

		end

		end

		singular = (value == 1)

		singular = (value == 1)

		local scientific

		local scientific

		local significand, exponent = clean:match('^([%d.]+)[Ee]([+%-]?%d+)')

		local significand, exponent = clean:match('^([%d.]+)[Ee]([+%-]?%d+)')

		if significand then

		if significand then

			show = with_exponent(parms, rounded(significand, significand, exponent), exponent)

			show = with_exponent(parms, rounded(significand, significand, exponent), exponent)

			scientific = true

			scientific = true

		else

		else

			show = with_separator(parms, rounded(value, clean))

			show = with_separator(parms, rounded(value, clean))

		end

		end

		show = propersign .. show

		show = propersign .. show

		if parms.opt_spell_in then

		if parms.opt_spell_in then

			show = spell_number(parms, 'in', propersign .. rounded(value, clean)) or show

			show = spell_number(parms, 'in', propersign .. rounded(value, clean)) or show

			scientific = false

			scientific = false

		end

		end

		if scientific then

		if scientific then

			parms.opt_scientific = true

			parms.opt_scientific = true

		end

		end

	end

	end

	if isnegative and (value ~= 0) then

	if isnegative and (value ~= 0) then

		value = -value

		value = -value

		altvalue = -(altvalue or value)

		altvalue = -(altvalue or value)

	end

	end

	return true, {

	return true, {

		value = value,

		value = value,

		altvalue = altvalue or value,

		altvalue = altvalue or value,

		singular = singular,

		singular = singular,

		clean = clean,

		clean = clean,

		show = show .. (reference or ''),

		show = show .. (reference or ''),

		denominator = denominator,

		denominator = denominator,

	}

	}

end

end

local function get_number(text)

local function get_number(text)

	-- Return v, f where:

	-- Return v, f where:

	--   v = nil (text is not a number)

	--   v = nil (text is not a number)

	-- or

	-- or

	--   v = value of text (text is a number)

	--   v = value of text (text is a number)

	--   f = true if value is an integer

	--   f = true if value is an integer

	-- Input can use en digits or digits in local language or separators,

	-- Input can use en digits or digits in local language or separators,

	-- but no Unicode minus, and no fraction.

	-- but no Unicode minus, and no fraction.

	if text then

	if text then

		local number = tonumber(to_en(text))

		local number = tonumber(to_en(text))

		if number then

		if number then

			local _, fracpart = math.modf(number)

			local _, fracpart = math.modf(number)

			return number, (fracpart == 0)

			return number, (fracpart == 0)

		end

		end

	end

	end

end

end

local function gcd(a, b)

local function gcd(a, b)

	-- Return the greatest common denominator for the given values,

	-- Return the greatest common denominator for the given values,

	-- which are known to be positive integers.

	-- which are known to be positive integers.

	if a > b then

	if a > b then

		a, b = b, a

		a, b = b, a

	end

	end

	if a <= 0 then

	if a <= 0 then

		return b

		return b

	end

	end

	local r = b % a

	local r = b % a

	if r <= 0 then

	if r <= 0 then

		return a

		return a

	end

	end

	if r == 1 then

	if r == 1 then

		return 1

		return 1

	end

	end

	return gcd(r, a)

	return gcd(r, a)

end

end

local function fraction_table(value, denominator)

local function fraction_table(value, denominator)

	-- Return value as a string or a table:

	-- Return value as a string or a table:

	-- * If result is a string, there is no fraction, and the result

	-- * If result is a string, there is no fraction, and the result

	--   is value formatted as a string of en digits.

	--   is value formatted as a string of en digits.

	-- * If result is a table, it represents a fraction with named fields:

	-- * If result is a table, it represents a fraction with named fields:

	--   wholestr, numstr, denstr (strings of en digits for integer, numerator, denominator).

	--   wholestr, numstr, denstr (strings of en digits for integer, numerator, denominator).

	-- The result is rounded to the nearest multiple of (1/denominator).

	-- The result is rounded to the nearest multiple of (1/denominator).

	-- If the multiple is zero, no fraction is included.

	-- If the multiple is zero, no fraction is included.

	-- No fraction is included if value is very large as the fraction would

	-- No fraction is included if value is very large as the fraction would

	-- be unhelpful, particularly if scientific notation is required.

	-- be unhelpful, particularly if scientific notation is required.

	-- Input value is a non-negative number.

	-- Input value is a non-negative number.