Module:Convert

-- Convert a value from one unit of measurement to another. -- Example: 123 lb --> 123 pounds (56 kg)

local MINUS = '−' -- Unicode U+2212 MINUS SIGN (UTF-8: e2 88 92) local abs = math.abs local floor = math.floor local format = string.format local log10 = math.log10 local ustring = mw.ustring local ulen = ustring.len local usub = ustring.sub

-- Configuration options to keep magic values in one location. -- Conversion data and message text are defined in separate modules. local config, maxsigfig local numdot, numsep -- each must be a single byte for simple regex search/replace local default_exceptions, link_exceptions, all_units local text_code 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 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. local group_method = 3    -- code for how many digits are in a group local per_word = 'per'    -- for units like "miles per gallon" local plural_suffix = 's' -- only other useful value is probably '' to disable plural unit names

-- 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. -- 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. local extra_module -- name of module with extra units local extra_units  -- nil or table of extra units from extra_module

local function boolean(text) -- Return true if text represents a "true" option value. if text then text = text:lower if text == 'on' or text == 'yes' then return true end end return false end

local function from_en(text) -- Input is a string representing a number in en digits with '.' decimal mark, -- without digit grouping (which is done just after calling this). -- Return the translation of the string with numdot and digits in local language. if numdot ~= '.' then text = text:gsub('%.', numdot) end if from_en_table then text = text:gsub('%d', from_en_table) end return text end

local function to_en(text) -- Input is a string representing a number in the local language with -- an optional numdot decimal mark and numsep digit grouping. -- Return the translation of the string with '.' mark and en digits, -- and no separators (they have to be removed here to handle cases like	-- numsep = '.' and numdot = ',' with input "1.234.567,8"). if numsep ~= '' then text = text:gsub('[' .. numsep .. ']', '') -- use '[x]' in case x is '.' end if numdot ~= '.' then text = text:gsub('[' .. numdot .. ']', '.') end if to_en_table then text = ustring.gsub(text, '%d', to_en_table) end return text end

local spell_module -- name of module that can spell numbers local speller      -- function from that module to handle spelling (set if spelling is wanted)

local function set_config(frame) -- Set configuration options from template #invoke or defaults. config = frame.args numdot = config.numdot or '.'      -- decimal mark before fractional digits numsep = config.numsep or ','      -- group separator for numbers (',', '.', '') maxsigfig = config.maxsigfig or 14 -- maximum number of significant figures -- Scribunto sets the global variable 'mw'. -- A testing program can set the global variable 'is_test_run'. local data_module, text_module, data_code if is_test_run then local langcode = mw.language.getContentLanguage.code data_module = "convertdata-" .. langcode text_module = "converttext-" .. langcode extra_module = "convertextra-" .. langcode spell_module = "ConvertNumeric" else local sandbox = boolean(config.sandbox) and '/sandbox' or '' data_module = "Module:Convert/data" .. sandbox text_module = "Module:Convert/text" .. sandbox extra_module = "Module:Convert/extra" .. sandbox spell_module = "Module:ConvertNumeric" end data_code = mw.loadData(data_module) text_code = mw.loadData(text_module) default_exceptions = data_code.default_exceptions link_exceptions = data_code.link_exceptions all_units = data_code.all_units local translation = text_code.translation_table if translation then if translation.group then group_method = translation.group end if translation.per_word then per_word = translation.per_word end if translation.plural_suffix then plural_suffix = translation.plural_suffix end varname = translation.varname from_en_table = translation.from_en local use_workaround = true if use_workaround then -- 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, -- if the table is accessed via mw.loadData. local source = translation.to_en if source then to_en_table = {} for k, v in pairs(source) do					to_en_table[k] = v				end end else to_en_table = translation.to_en end end end

local function collection -- Return a table to hold items. return { n = 0, add = function (self, item) self.n = self.n + 1 self[self.n] = item end, } end

local function divide(numerator, denominator) -- Return integers quotient, remainder resulting from dividing the two -- given numbers, which should be unsigned integers. local quotient, remainder = floor(numerator / denominator), numerator % denominator if not (0 <= remainder and remainder < denominator) then -- Floating point limits may need this, as in 160.02 Ym. remainder = 0 end return quotient, remainder end

local function split(text, delimiter) -- Return a numbered table with fields from splitting text. -- The delimiter is used in a regex without escaping (for example, '.' would fail). -- Each field has any leading/trailing whitespace removed. local t = {} text = text .. delimiter -- to get last item for item in text:gmatch('%s*(.-)%s*' .. delimiter) do		table.insert(t, item) end return t end

local function strip(text) -- If text is a string, return its content with no leading/trailing -- whitespace. Otherwise return nil (a nil argument gives a nil result). if type(text) == 'string' then return text:match("^%s*(.-)%s*$") end end

local function wanted_category(cat) -- Return cat if it is wanted in current namespace, otherwise return nil. -- This is so tracking categories only include pages that need correction. local title = mw.title.getCurrentTitle if title then local nsdefault = '0' -- default namespace: '0' = article; '0,10' = article and template local namespace = title.namespace for _, v in ipairs(split(config.nscat or nsdefault, ',')) do			if namespace == tonumber(v) then return cat end end end end

local function message(mcode) -- Return wikitext for an error message, including category if specified -- for the message type. -- mcode = numbered table specifying the message: --   mcode[1] = 'cvt_xxx' (string used as a key to get message info) --   mcode[2] = 'parm1' (string to replace first %s if any in message) --   mcode[3] = 'parm2' (string to replace second %s if any in message) --   mcode[4] = 'parm3' (string to replace third %s if any in message) local msg = text_code.all_messages[mcode[1]] local nowiki = mw.text.nowiki if msg then local parts = {} local regex, replace = msg.regex, msg.replace for i = 1, 3 do			local limit = 40 local s = mcode[i + 1] if s then if regex and replace then s = s:gsub(regex, replace) limit = nil -- allow long "should be" messages end -- Escape user input so it does not break the message. -- To avoid reference tags (like 1 m) or other tags -- breaking the mouseover title, any strip marker starting with char(127) is -- replaced with escaped ' ' or '...' (text not needing i18n). local append = '' local pos = s:find(string.char(127), 1, true) if pos then if s:find('-ref-', 1, true) then append = '&lt;ref&gt;...&lt;/ref&gt;' else append = '...' end s = s:sub(1, pos - 1) end if limit and ulen(s) > limit then s = usub(s, 1, limit) if append == '' then append = '...' end end s = nowiki(s) .. append else s = '?' end parts[i] = s		end local title = format(msg[1] or 'Missing message', parts[1], parts[2], parts[3]) local text = msg[2] or 'Missing message' local cat = wanted_category(text_code.all_categories[msg[3]]) or '' local anchor = msg[4] or '' local fmt = text_code.all_messages['cvt_format'] or 'convert: bug' title = title:gsub('"', '&quot;')		return format(fmt, anchor, title, text, cat)	end	return 'Convert internal error: unknown message' end

local function add_warning(parms, level, mcode, text) -- If enabled, add a warning that will be displayed after the convert result. -- To reduce output noise, only the first warning is displayed. if config.warnings then if level <= (tonumber(config.warnings) or 1) then if parms.warnings == nil then parms.warnings = message({ mcode, text }) end end end end

local function spell_number(parms, inout, number, numerator, denominator) -- Return result of spelling (number, numerator, denominator), or -- return nil if spelling is not available or not supported for given text. -- Examples (each value must be a string or nil): --  number  numerator  denominator  output --  --  -  ---  ---	--   "1.23"    nil        nil        one point two three --   "1"      "2"        "3"        one and two thirds --   nil      "2"        "3"        two thirds if not speller then local function get_speller(module) return require(module).spell_number end local success success, speller = pcall(get_speller, spell_module) if not success or type(speller) ~= 'function' then add_warning(parms, 1, 'cvt_no_spell') return nil end end local case if parms.spell_upper == inout then case = true parms.spell_upper = nil -- only uppercase first word in a multiple unit end local sp = not parms.opt_sp_us local adj = parms.opt_adjectival return speller(number, numerator, denominator, case, sp, adj) end

-- BEGIN: Code required only for built-in units. -- LATER: If need much more code, move to another module to simplify this module. local function speed_of_sound(altitude) -- This is for the Mach built-in unit of speed. -- Return speed of sound in metres per second at given altitude in feet. -- If no altitude given, use default (zero altitude = sea level). -- Table gives speed of sound in miles per hour at various altitudes: --  altitude = -17,499 to 302,499 feet -- mach_table[a + 4] = s where --  a = (altitude / 5000) rounded to nearest integer (-3 to 60) --  s = speed of sound (mph) at that altitude -- LATER: Should calculate result from an interpolation between the next -- lower and higher altitudes in table, rather than rounding to nearest. -- From: http://www.aerospaceweb.org/question/atmosphere/q0112.shtml local mach_table = {                                                      -- a = 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 10 660.1, 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 30 737.3, 737.7, 737.7, 736.2, 730.5, 724.6, 718.8, 712.9, 707.0, 701.1, -- 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 50 639.1, 634.4, 629.6, 624.8, 620.0, 615.2, 613.2, 613.2, 613.2, 613.5, -- 51 to 60 }	altitude = altitude or 0 local a = (altitude < 0) and -altitude or altitude a = floor(a / 5000 + 0.5) if altitude < 0 then a = -a end if a < -3 then a = -3 elseif a > 60 then a = 60 end return mach_table[a + 4] * 0.44704 -- mph converted to m/s end -- END: Code required only for built-in units.

local function check_mismatch(unit1, unit2) -- If unit1 cannot be converted to unit2, return an error message table. -- This allows conversion between units of the same type, and between -- Nm (normally torque) and ftlb (energy), as in gun-related articles. -- This works because Nm is the base unit (scale = 1) for both the -- 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 -- the alternate type of unit2, and vice versa. That provides a whitelist -- of which conversions are permitted between normally incompatible types. if unit1.utype == unit2.utype or		(unit1.utype == unit2.alttype and unit1.alttype == unit2.utype) then return nil end return { 'cvt_mismatch', unit1.utype, unit2.utype } end

local function override_from(out_table, in_table, fields) -- Copy the specified fields from in_table to out_table, but do not -- copy nil fields (keep any corresponding field in out_table). for _, field in ipairs(fields) do		if in_table[field] then out_table[field] = in_table[field] end end end

local function shallow_copy(t) -- Return a shallow copy of table t. -- Do not need the features and overhead of the Scribunto mw.clone. local result = {} for k, v in pairs(t) do		result[k] = v	end return result end

local unit_mt = { -- Metatable to get missing values for a unit that does not accept SI prefixes, -- or for a unit that accepts prefixes but where no prefix was used. -- In the latter case, and before use, fields symbol, name1, name1_us -- must be set from _symbol, _name1, _name1_us respectively. -- 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. __index = function (self, key) local value if key == 'name1' or key == 'sym_us' then value = self.symbol elseif key == 'name2' then value = self.name1 .. plural_suffix elseif key == 'name1_us' then value = self.name1 if not rawget(self, 'name2_us') then -- If name1_us is 'foot', do not make name2_us by appending plural_suffix. self.name2_us = self.name2 end elseif key == 'name2_us' then local raw1_us = rawget(self, 'name1_us') if raw1_us then value = raw1_us .. plural_suffix else value = self.name2 end elseif key == 'link' then value = self.name1 else value = false end rawset(self, key, value) return value end }

local unit_prefixed_mt = { -- Metatable to get missing values for a unit that accepts SI prefixes, -- and where a prefix has been used. -- Before use, fields si_name, si_prefix must be defined. __index = function (self, key) local value if key == 'symbol' then value = self.si_prefix .. self._symbol elseif key == 'sym_us' then value = self.symbol -- always the same as sym_us for prefixed units elseif key == 'name1' then -- prefix_position is a byte (not character) position, so use Lua's sub. local pos = rawget(self, 'prefix_position') or 1 value = self._name1 value = value:sub(1, pos - 1) .. self.si_name .. value:sub(pos) elseif key == 'name2' then value = self.name1 .. plural_suffix elseif key == 'name1_us' then value = rawget(self, '_name1_us') if value then local pos = rawget(self, 'prefix_position') or 1 value = value:sub(1, pos - 1) .. self.si_name .. value:sub(pos) else value = self.name1 end elseif key == 'name2_us' then if rawget(self, '_name1_us') then value = self.name1_us .. plural_suffix else value = self.name2 end elseif key == 'link' then value = self.name1 else value = false end rawset(self, key, value) return value end }

local unit_per_mt = { -- 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 -- are handled as a special case. __index = function (self, key) local value if key == 'symbol' then local per = self.per local unit1, unit2 = per[1], per[2] if unit1 then value = unit1[key] .. '/' .. unit2[key] else value = '/' .. unit2[key] end elseif key == 'sym_us' then value = self.symbol elseif key == 'scale' then local per = self.per local unit1, unit2 = per[1], per[2] value = (unit1 and unit1.scale or 1) * self.scalemultiplier / unit2.scale else value = false end rawset(self, key, value) return value end }

local function lookup(unitcode, opt_sp_us, what, utable, fails, depth) -- 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. -- Parameter opt_sp_us is true for US spelling of SI prefixes and -- the symbol and name of the unit. If true, the result includes field -- sp_us = true (that field may also have been in the unit definition). -- Parameter 'what' determines whether combination units are accepted: --  'no_combination'  : single unit only --  'any_combination' : single unit or combination or output multiple --  'only_multiple'   : single unit or output multiple only -- 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; -- otherwise the prefix ('k') is applied to the base unit ('g'). -- If unitcode is a known combination code (and if allowed by what), -- a table of output multiple unit tables is included in the result. -- For compatibility with the old template, an underscore in a unitcode is -- replaced with a space so usage like 350 board_feet works. -- Wikignomes may also put two spaces or " " in combinations, so -- replace underscore, " ", and multiple spaces with a single space. utable = utable or all_units fails = fails or {} depth = depth and depth + 1 or 1 if depth > 9 then -- There are ways to mistakenly define units which result in infinite -- recursion when lookup is called. That gives a long delay and very -- confusing error messages, so the depth parameter is used as a guard. return false, { 'cvt_lookup', unitcode } end if unitcode == nil or unitcode == '' then return false, { 'cvt_no_unit' } end unitcode = unitcode:gsub('_', ' '):gsub(' ', ' '):gsub(' +', ' ') local t = utable[unitcode] if t then if t.shouldbe then return false, { 'cvt_should_be', t.shouldbe } end local force_sp_us = opt_sp_us if t.sp_us then force_sp_us = true opt_sp_us = true end local target = t.target -- nil, or unitcode is an alias for this target if target then local success, result = lookup(target, opt_sp_us, what, utable, fails, depth) if not success then return false, result end override_from(result, t, { 'customary', 'default', 'link', 'symbol', 'symlink' }) local multiplier = t.multiplier if multiplier then result.multiplier = tostring(multiplier) result.scale = result.scale * multiplier end return true, result end local per = t.per -- nil/false, or a numbered table for "x/y" units if per then local result = { utype = t.utype, per = {} } result.scalemultiplier = t.multiplier or 1 override_from(result, t, { 'invert', 'iscomplex', 'default', 'link', 'symbol', 'symlink' }) result.symbol_raw = (result.symbol or false) -- to distinguish between a defined exception and a metatable calculation local cvt = result.per local prefix for i, v in ipairs(per) do				if i == 1 and text_code.currency[v] then prefix = v				else local success, t = lookup(v, opt_sp_us, 'no_combination', utable, fails, depth) if not success then return false, t end cvt[i] = t					if t.sp_us then -- if the top or bottom unit forces sp=us, set the per unit to use the correct name/symbol force_sp_us = true end end end if prefix then result.vprefix = prefix else result.vprefix = false -- to avoid calling __index end result.sp_us = force_sp_us return true, setmetatable(result, unit_per_mt) end local combo = t.combination -- nil or a table of unitcodes if combo then local multiple = t.multiple if what == 'no_combination' or (what == 'only_multiple' and not multiple) then return false, { 'cvt_bad_unit', unitcode } end -- Recursively create a combination table containing the -- converter table of each unitcode. local result = { utype = t.utype, multiple = multiple, combination = {} } local cvt = result.combination for i, v in ipairs(combo) do				local success, t = lookup(v, opt_sp_us, multiple and 'no_combination' or 'only_multiple', utable, fails, depth) if not success then return false, t end cvt[i] = t			end return true, result end local result = shallow_copy(t) result.sp_us = force_sp_us if result.prefixes then result.symbol = result._symbol result.name1 = result._name1 result.name1_us = result._name1_us end return true, setmetatable(result, unit_mt) end local SIprefixes = text_code.SIprefixes for plen = SIprefixes[1] or 2, 1, -1 do -- Look for an SI prefix; should never occur with an alias. -- Check for longer prefix first ('dam' is decametre). -- SIprefixes[1] = prefix maximum #characters (as seen by mw.ustring.sub). local prefix = usub(unitcode, 1, plen) local si = SIprefixes[prefix] if si then local t = utable[usub(unitcode, plen+1)] if t and t.prefixes then local result = shallow_copy(t) if opt_sp_us then result.sp_us = true end if result.sp_us and si.name_us then result.si_name = si.name_us else result.si_name = si.name end result.si_prefix = si.prefix or prefix result.scale = t.scale * 10 ^ (si.exponent * t.prefixes) return true, setmetatable(result, unit_prefixed_mt) end end end -- Accept any unit with an engineering notation prefix like "e6cuft" -- (million cubic feet), but not chained prefixes like "e3e6cuft", -- and not if the unit is a combination or multiple, -- and not if the unit has an offset or is a built-in. -- Only en digits are accepted. local has_plus = unitcode:find('+', 1, true) if not has_plus then local exponent, baseunit = unitcode:match('^e(%d+)(.*)') if exponent then local engscale = text_code.eng_scales[exponent] if engscale then local success, result = lookup(baseunit, opt_sp_us, 'no_combination', utable, fails, depth) if not success then return false, result end if not (result.offset or result.builtin or result.engscale) then result.defkey = unitcode -- key to lookup default exception result.engscale = engscale result.scale = result.scale * 10 ^ tonumber(exponent) return true, result end end end end -- 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 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. local err_is_fatal local combo = collection if has_plus then err_is_fatal = true for item in (unitcode .. '+'):gmatch('%s*(.-)%s*%+') do			if item ~= '' then combo:add(item) end end elseif unitcode:find('%s') then for item in unitcode:gmatch('%S+') do			combo:add(item) end end if combo.n > 1 then local function lookup_combo if what == 'no_combination' or what == 'only_multiple' then return false, { 'cvt_bad_unit', unitcode } end local result = { combination = {} } local cvt = result.combination for i, v in ipairs(combo) do				local success, t = lookup(v, opt_sp_us, 'only_multiple', utable, fails, depth) if not success then return false, t end if i == 1 then result.utype = t.utype else local mismatch = check_mismatch(result, t)					if mismatch then return false, mismatch end end cvt[i] = t			end return true, result end local success, result = lookup_combo if success or err_is_fatal then return success, result end end if not extra_units then local success, extra = pcall(function return require(extra_module).extra_units end) if success and type(extra) == 'table' then extra_units = extra end end if extra_units then -- 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. if not fails[unitcode] then fails[unitcode] = true local other = (utable == all_units) and extra_units or all_units local success, result = lookup(unitcode, opt_sp_us, what, other, fails, depth) if success then return true, result end end end return false, { 'cvt_unknown', unitcode } end

local function valid_number(num) -- Return true if num is a valid number. -- In Scribunto (different from some standard Lua), when expressed as a string, -- overflow or other problems are indicated with text like "inf" or "nan" -- which are regarded as invalid here (each contains "n"). if type(num) == 'number' and tostring(num):find('n', 1, true) == nil then return true end end

local function ntsh(num, debug) -- Return html text to be used for a hidden sort key so that -- the given number will be sorted in numeric order. -- If debug == true, output is in a box (not hidden). -- This implements Template:Ntsh (number table sorting, hidden). local result, style if not valid_number(num) then if num < 0 then result = '1000000000000000000' else result = '9000000000000000000' end elseif num == 0 then result = '5000000000000000000' else local mag = floor(log10(abs(num)) + 1e-14) local prefix if num > 0 then prefix = 7000 + mag else prefix = 2999 - mag num = num + 10^(mag+1) end result = format('%d', prefix) .. format('%015.0f', floor(num * 10^(14-mag))) end if debug then style = 'border:1px solid' else style = 'display:none' end return ' ' .. result .. ' ' end

local function hyphenated(name, parts) -- 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. -- Hypothetical examples: --  ton         →  ton          (no change) --  long ton       →  long-ton --  long ton  →  long-ton --  long ton             →  long-ton -- Input can also have multiple links in a single name like: --  U.S. gallon --  miles per U.S. quart --  long tons per short ton -- Assume that links cannot be nested (never like "abc[[defghi]]"). -- This uses a simple and efficient procedure that works for most cases. -- Some units (if used) would require more, and can later think about -- adding a method to handle exceptions. -- The procedure is to replace each space with a hyphen, but -- not a space after ')' [for "(pre-1954 US) nautical mile"], and	-- not spaces immediately before '(' or in '(...)' [for cases like -- "British thermal unit (ISO)" and "Calorie (International Steam Table)"]. if name:find(' ', 1, true) then if parts then local pos if name:sub(1, 1) == '(' then				pos = name:find(')', 1, true) if pos then return name:sub(1, pos+1) .. name:sub(pos+2):gsub(' ', '-') end elseif name:sub(-1, -1) == ')' then				pos = name:find('(', 1, true) if pos then return name:sub(1, pos-2):gsub(' ', '-') .. name:sub(pos-1) end end return name:gsub(' ', '-') end parts = collection for before, item, after in name:gmatch('([^[]*)(%[%', 1, true)				if plen then					prefix = item:sub(1, plen)					item = item:sub(plen + 1, -3)				else					prefix = item:sub(1, -3) .. '|'					item = item:sub(3, -3)				end				item = prefix .. hyphenated(item, parts) .. '' end parts:add(before:gsub(' ', '-') .. item .. after:gsub(' ', '-')) end if parts.n == 0 then -- No link like "..." was found in the original name. parts:add(hyphenated(name, parts)) end return table.concat(parts) end return name end

local function hyphenated_maybe(parms, want_name, sep, id, inout) -- Return s, f where --  s = id, possibly modified --  f = true if hyphenated -- Possible modifications: hyphenate; prepend '-'; append mid text. if id == nil or id == '' then return '' end local mid if parms.opt_adjectival then if inout == (parms.opt_flip and 'out' or 'in') then mid = parms.mid end if want_name then return '-' .. hyphenated(id) .. (mid or ''), true end end return sep .. id .. (mid or '') end

local function change_sign(text) -- Change sign of text for correct appearance because it is negated. if text:sub(1, 1) == '-' then return text:sub(2) end return '-' .. text end

local function use_minus(text) -- Return text with Unicode minus instead of '-', if present. if text:sub(1, 1) == '-' then return MINUS .. text:sub(2) end return text end

local function digit_grouper(method, gaps) -- Return a table to hold groups of digits which can be joined with -- suitable separators (such as commas). -- Each group is separately translated to the local language because -- gap separators include digits which should not be translated. -- Parameter method is a number or nil: --  3 for 3-digit grouping, or --  2 for 3-then-2 grouping. -- Parameter gaps is true to use gaps (numsep ignored). return { n = 0, add = function (self, digits) self.n = self.n + 1 self[self.n] = from_en(digits) end, join = function (self, rhs) -- Concatenate in reverse order. if gaps then local result = '' for i = 1, self.n - 1 do result = ' ' .. self[i] .. ' ' .. result end return ' ' .. self[self.n] .. result .. from_en(rhs) .. ' '			else local result = self[1] for i = 2, self.n do result = self[i] .. numsep .. result end return result .. from_en(rhs) end end, step = 3, next_position = function (self, previous) -- Return position of digit just before next group. -- Digits are grouped from right-to-left (least significant first). local result = previous - self.step if method == 2 then self.step = 2 end return (result < 0) and 0 or result end, } end

local function with_separator(parms, text) -- Input text is a number in en digits and optional '.' decimal mark. -- Return an equivalent of text, formatted for display: --  with a custom decimal mark instead of '.', if wanted --  with thousand separators inserted, if wanted --  digits in local language -- The given text is like '123' or '12345.6789' or '1.23e45' -- (e notation can only occur when processing an input value). -- The text has no sign (caller inserts that later, if necessary). -- Separator is inserted only in the integer part of the significand -- (not after the decimal mark, and not after 'e' or 'E'). if parms.opt_nocomma or numsep == '' then return from_en(text) end local last = text:match('[.eE]') --  returns position if last == nil then last = #text else last = last - 1 -- index of last character before dot/e/E end if last < 4 or (last == 4 and parms.opt_comma5) then return from_en(text) end local groups = digit_grouper(group_method, parms.opt_gaps) local i = last while i > 0 do		local position = groups:next_position(i) groups:add(text:sub(position+1, i)) i = position end return groups:join(text:sub(last+1)) end

-- Input values can use values like 1.23e12, but are never displayed -- using scientific notation like 1.23×10¹². -- Very small or very large output values use scientific notation. -- Use format(fmtpower, significand, '10', exponent) where each arg is a string. local fmtpower = '%s × %s%s'

local function with_exponent(show, exponent) -- Return wikitext to display the implied value in scientific notation. -- Input uses en digits; output uses digits in local language. if #show > 1 then show = show:sub(1, 1) .. '.' .. show:sub(2) end return format(fmtpower, from_en(show), from_en('10'), use_minus(from_en(tostring(exponent)))) end

local function make_sigfig(value, sigfig) -- Return show, exponent that are equivalent to the result of	-- converting the number 'value' (where value >= 0) to a string, -- rounded to 'sigfig' significant figures. -- The returned items are: --  show: a string of digits; no sign and no dot; --        there is an implied dot before show. --  exponent: a number (an integer) to shift the implied dot. -- Resulting value = tonumber('.' .. show) * 10^exponent. -- Examples: --  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, 3) returns '000', 1 (.000 * 10^1). if sigfig <= 0 then sigfig = 1 elseif sigfig > maxsigfig then sigfig = maxsigfig end if value == 0 then return string.rep('0', sigfig), 1 end local exp, fracpart = math.modf(log10(value)) if fracpart >= 0 then fracpart = fracpart - 1 exp = exp + 1 end local digits = format('%.0f', 10^(fracpart + sigfig)) if #digits > sigfig then -- Overflow (for sigfig=3: like 0.9999 rounding to "1000"; need "100"). digits = digits:sub(1, sigfig) exp = exp + 1 end assert(#digits == sigfig, 'Bug: rounded number has wrong length') return digits, exp end

-- Fraction output format. local fracfmt = { { -- Like 1/undefined (fraction slash). -- 1/2   : sign, numerator, denominator -- 1+2/3 : signed_wholenumber, numerator, denominator ' %s%s&frasl;%s ', ' %s %s&frasl;%s ', },	{ -- Like 1⁄undefined (fraction horizontal bar). -- 1//2  : sign, numerator, denominator (sign should probably be before the fraction, but then it can wrap, and html is already too long) -- 1+2//3 : signed_wholenumber, numerator, denominator ' %s%s / %s ', ' %s %s / %s   ', }, }

local function format_fraction(parms, inout, negative, wholestr, numstr, denstr, do_spell, style) -- Return wikitext for a fraction, possibly spelled. -- Inputs use en digits and have no sign; output uses digits in local language. local wikitext if not style then style = parms.opt_fraction_horizontal and 2 or 1 end if wholestr == '' then wholestr = nil end if wholestr then local decorated = with_separator(parms, wholestr) if negative then decorated = MINUS .. decorated end local fmt = fracfmt[style][2] wikitext = format(fmt, decorated, from_en(numstr), from_en(denstr)) else local sign = negative and MINUS or '' wikitext = format(fracfmt[style][1], sign, from_en(numstr), from_en(denstr)) end if do_spell then if negative then if wholestr then wholestr = '-' .. wholestr else numstr = '-' .. numstr end end wikitext = spell_number(parms, inout, wholestr, numstr, denstr) or wikitext end return wikitext end

local function format_number(parms, show, exponent, isnegative) -- Parameter show is a string or a table containing strings. -- Each string is a formatted number in en digits and optional '.' decimal mark. -- A table represents a fraction: integer, numerator, denominator; -- if a table is given, exponent must be nil. -- Return t where t is a table with fields: --  show = wikitext formatted to display implied value --         (digits in local language) --  is_scientific = true if show uses scientific notation --  clean = unformatted show (possibly adjusted and with inserted '.') --         (en digits) --  sign = '' or MINUS --  exponent = exponent (possibly adjusted) -- The clean and exponent fields can be used to calculate the -- rounded absolute value, if needed. --	-- The value implied by the arguments is found from: --  exponent is nil; and --  show is a string of digits (no sign), with an optional dot; --  show = '123.4' is value 123.4, '1234' is value 1234.0; -- or: --  exponent is an integer indicating where dot should be; --  show is a string of digits (no sign and no dot); --  there is an implied dot before show; --  show does not start with '0'; --  show = '1234', exponent = 3 is value 0.1234*10^3 = 123.4. --	-- The formatted result: -- * Is for an output value and is spelled if wanted and possible. -- * Includes a Unicode minus if isnegative and not spelled. -- * Uses a custom decimal mark, if wanted. -- * Has digits grouped where necessary, if wanted. -- * Uses scientific notation for very small or large values --  (which forces output to not be spelled). -- * Has no more than maxsigfig significant digits --  (same as old template and ). local sign = isnegative and MINUS or '' local maxlen = maxsigfig local tfrac if type(show) == 'table' then tfrac = show show = tfrac.wholestr assert(exponent == nil, 'Bug: exponent given with fraction') end if not tfrac and not exponent then local integer, dot, decimals = show:match('^(%d*)(%.?)(.*)') if #integer >= 10 then show = integer .. decimals exponent = #integer elseif integer == '0' or integer == '' then local zeros, figs = decimals:match('^(0*)([^0]?.*)') if #figs == 0 then if #zeros > maxlen then show = '0.' .. zeros:sub(1, maxlen) end elseif #zeros >= 4 then show = figs exponent = -#zeros elseif #figs > maxlen then show = '0.' .. zeros .. figs:sub(1, maxlen) end else maxlen = maxlen + #dot if #show > maxlen then show = show:sub(1, maxlen) end end end if exponent then if #show > maxlen then show = show:sub(1, maxlen) end if exponent > 10 or exponent <= -4 or (exponent == 10 and show ~= '1000000000') then -- Rounded value satisfies: value >= 1e9 or value < 1e-4 (1e9 = 0.1e10). return { clean = '.' .. show, exponent = exponent, sign = sign, show = sign .. with_exponent(show, exponent-1), is_scientific = true, }		end if exponent >= #show then show = show .. string.rep('0', exponent - #show) -- result has no dot elseif exponent <= 0 then show = '0.' .. string.rep('0', -exponent) .. show else show = show:sub(1, exponent) .. '.' .. show:sub(exponent+1) end end local formatted_show if tfrac then 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) else if isnegative and show:match('^0.?0*$') then sign = '' -- don't show minus if result is negative but rounds to zero end formatted_show = sign .. with_separator(parms, show) if parms.opt_spell_out then formatted_show = spell_number(parms, 'out', sign .. show) or formatted_show end end return { clean = show, sign = sign, show = formatted_show, is_scientific = false, -- to avoid calling __index } end

local function extract_fraction(parms, text, negative) -- If text represents a fraction, return --  value, altvalue, show, spelled, denominator -- where --  value is a number (value of the fraction in argument text) --  altvalue is an alternate interpretation of any fraction for the hands --       unit where "14.1+3/4" means 14 hands 1.75 inches! --  show is a string (formatted text for display of an input value,	--        and is spelled if wanted and possible) --  spelled is true if show was spelled --  denominator is value of the denominator in the fraction -- Otherwise, return nil. -- Input uses en digits and '.' decimal mark (input has been translated). -- Output uses digits in local language and custom decimal mark, if any. --	-- In the following, '(3/8)' represents the wikitext required to -- display a fraction with numerator 3 and denominator 8. -- In the wikitext, Unicode minus is used for a negative value. --  text          value, show            value, show --                if not negative       if negative --  3 / 8         0.375, '(3/8)'        -0.375, '−(3/8)'	--   2 + 3 / 8     2.375, '2(3/8)'       -1.625, '−2(−3/8)'	--   2 - 3 / 8     1.625, '2(−3/8)'      -2.375, '−2(3/8)'	--   1 + 20/8      3.5 , '1/(20/8)'     1.5   , '−1/(−20/8)'	--   1 - 20/8      -1.5., '1(−20/8)'     -3.5  , '−1(20/8)'	-- Wherever an integer appears above, numbers like 1.25 or 12.5e-3 -- (which may be negative) are also accepted (like old template). -- Old template interprets '1.23e+2+12/24' as '123(12/24)' = 123.5! local numstr, whole, value, altvalue local lhs, slash, denstr = text:match('^%s*([^/]-)%s*(/+)%s*(.-)%s*$') local denominator = tonumber(denstr) if denominator == nil then return nil end local wholestr, negfrac, rhs = lhs:match('^%s*(.-[^eE])%s*([+-])%s*(.-)%s*$') if wholestr == nil or wholestr == '' then wholestr = nil whole = 0 numstr = lhs else whole = tonumber(wholestr) if whole == nil then return nil end numstr = rhs end negfrac = (negfrac == '-') local numerator = tonumber(numstr) if numerator == nil then return nil end -- Spelling of silly inputs like "-2+3/8" or "2+3/+8" (mixed or excess signs) is not supported. local do_spell if negative == negfrac or wholestr == nil then value = whole + numerator / denominator altvalue = whole + numerator / (denominator * 10) do_spell = parms.opt_spell_in if do_spell then if not (numstr:match('^%d') and denstr:match('^%d')) then -- if either has a sign do_spell = false end end else value = whole - numerator / denominator altvalue = whole - numerator / (denominator * 10) numstr = change_sign(numstr) do_spell = false end if not valid_number(value) then return nil -- overflow or similar end numstr = use_minus(numstr) denstr = use_minus(denstr) local style = #slash -- kludge: 1 or 2 slashes can be used to select style if style > 2 then style = 2 end local wikitext = format_fraction(parms, 'in', negative, wholestr, numstr, denstr, do_spell, style) return value, altvalue, wikitext, do_spell, denominator end

local function extract_number(parms, text, another, no_fraction) -- Return true, info if can extract a number from text, -- where info is a table with the result, -- or return false, t where t is an error message table. -- Input can use en digits or digits in local language. -- Parameter another = true if the expected value is not the first. -- Before processing, the input text is cleaned: -- * Any thousand separators (valid or not) are removed. -- * Any sign (and optional following whitespace) is replaced with --  '-' (if negative) or '' (otherwise). --  That replaces Unicode minus with '-'. -- If successful, the returned info table contains named fields: --  value    = a valid number --  altvalue = a valid number, usually same as value but different --             if fraction used (for hands unit) --  singular = true if value is 1 (to use singular form of units) --           = false if value is -1 (like old template) --  clean    = cleaned text with any separators and sign removed --             (en digits and '.' decimal mark) --  show     = text formatted for output --             (digits in local language and custom decimal mark) -- The resulting show: -- * Is for an input value and is spelled if wanted and possible. -- * Has a rounded value, if wanted. -- * Has digits grouped where necessary, if wanted. -- * If negative, a Unicode minus is used; otherwise the sign is --  '+' (if the input text used '+'), or is '' (if no sign in input). text = strip(text or '') local clean = to_en(text) if clean == '' then return false, { another and 'cvt_no_num2' or 'cvt_no_num' } end local isnegative, propersign = false, '' -- most common case local singular, show, denominator local value = tonumber(clean) local altvalue if value then local sign = clean:sub(1, 1) if sign == '+' or sign == '-' then propersign = (sign == '+') and '+' or MINUS clean = clean:sub(2) end if value < 0 then isnegative = true value = -value end else local valstr for _, prefix in ipairs({ '-', MINUS, '&minus;' }) do -- Including '-' means inputs like '- 2' (with space) are accepted as -2. -- It also sets isnegative in case input is a fraction like '-2-3/4'. local plen = #prefix if clean:sub(1, plen) == prefix then valstr = clean:sub(plen + 1) break end end if valstr then isnegative = true propersign = MINUS clean = valstr value = tonumber(clean) end if value == nil then local spelled if not no_fraction then value, altvalue, show, spelled, denominator = extract_fraction(parms, clean, isnegative) end if value == nil then return false, { 'cvt_bad_num', text } end if value <= 1 then singular = true -- for example, "½ mile" or "one half mile" (singular unit) end end end if not valid_number(value) then -- for example, "1e310" may overflow return false, { 'cvt_invalid_num' } end if show == nil then singular = (value == 1 and not isnegative) local precision = parms.input_precision if precision and 0 <= precision and precision <= 8 then local fmt = '%.' .. format('%d', precision) .. 'f'			show = fmt:format(value + 2e-14) -- fudge for some common cases of bad rounding else show = clean end show = propersign .. with_separator(parms, show) if parms.opt_spell_in then show = spell_number(parms, 'in', propersign .. clean) or show end end local altvalue = altvalue or value if isnegative and (value ~= 0) then value = -value altvalue = -altvalue end return true, { value = value, altvalue = altvalue, singular = singular, clean = clean, show = show, denominator = denominator, } end

local function get_number(text) -- Return v, f where: --  v = nil (text is not a number) -- or	--  v = value of text (text is a number) --  f = true if value is an integer -- Input can use en digits or digits in local language, -- but no separators, no Unicode minus, and no fraction. if text then local number = tonumber(to_en(text)) if number then local integer, fracpart = math.modf(number) return number, (fracpart == 0) end end end

local function gcd(a, b)	-- Return the greatest common denominator for the given values, -- which are known to be positive integers. if a > b then a, b = b, a	end if a <= 0 then return b	end local r = b % a	if r <= 0 then return a	end if r == 1 then return 1 end return gcd(r, a) end

local function fraction_table(value, denominator) -- Return value as a string or a table: -- * If result is a string, there is no fraction, and the result --  is value formatted as a string of en digits. -- * If result is a table, it represents a fraction with named fields: --  wholestr, numstr, denstr (strings of en digits for integer, numerator, denominator). -- The result is rounded to the nearest multiple of (1/denominator). -- If the multiple is zero, no fraction is included. -- No fraction is included if value is very large as the fraction would -- be unhelpful, particularly if scientific notation is required. -- Input value is a non-negative number. -- Input denominator is a positive integer for the desired fraction. if value <= 0 then return '0' end if denominator <= 0 or value > 1e8 then return format('%.2f', value) end local integer, decimals = math.modf(value) local numerator = floor((decimals * denominator) +		0.5 + 2e-14) -- add fudge for some common cases of bad rounding if numerator >= denominator then integer = integer + 1 numerator = 0 end local wholestr = tostring(integer) if numerator > 0 then local div = gcd(numerator, denominator) if div > 1 then numerator = numerator / div denominator = denominator / div end return { wholestr = (integer > 0) and wholestr or '', numstr = tostring(numerator), denstr = tostring(denominator), value = value, }	end return wholestr end

local function preunits(count, preunit1, preunit2) -- If count is 1: --    ignore preunit2 --    return p1	-- else: --    preunit1 is used for preunit2 if the latter is empty --    return p1, p2	-- where: --    p1 is text to insert before the input unit --    p2 is text to insert before the output unit --    p1 or p2 may be nil to mean "no preunit" -- Using '+ ' gives output like "5+ feet" (no preceding space). local function withspace(text, i) -- Insert space at beginning if i == 1, or at end if i == -1. -- However, no space is inserted if there is a space or ' ' -- or '-' at that position ('-' is for adjectival text). local current = text:sub(i, i)		if current == ' ' or current == '-' then return text end if i == 1 then current = text:sub(1, 6) else current = text:sub(-6, -1) end if current == ' ' then return text end if i == 1 then return ' ' .. text end return text .. ' '	end preunit1 = preunit1 or '' local trim1 = strip(preunit1) if count == 1 then if trim1 == '' then return nil end return withspace(withspace(preunit1, 1), -1) end preunit2 = preunit2 or '' local trim2 = strip(preunit2) if trim1 ==  and trim2 ==  then return nil, nil end if trim1 ~= '+' then preunit1 = withspace(preunit1, 1) end if trim2 == '&#32;' then -- trick to make preunit2 empty preunit2 = nil elseif trim2 == '' then preunit2 = preunit1 elseif trim2 ~= '+' then preunit2 = withspace(preunit2, 1) end return preunit1, preunit2 end

local function range_text(range, want_name, parms, before, after) -- Return before .. rtext .. after -- where rtext is the text that separates two values in a range. local rtext, adj_text, exception if type(range) == 'table' then -- Table must specify range text for abbr=off and for abbr=on, -- and may specify range text for 'adj=on', -- and may specify exception = true. rtext = range[want_name and 'off' or 'on'] adj_text = range['adj'] exception = range['exception'] else rtext = range end if parms.opt_adjectival then if want_name or (exception and parms.abbr_org == 'on') then rtext = adj_text or rtext:gsub(' ', '-'):gsub(' ', '-') end end if rtext == '–' and after:sub(1, #MINUS) == MINUS then rtext = ' – ' end return before .. rtext .. after end

local function get_composite(parms, iparm, total, in_unit_table) -- Look for a composite input unit. For example, "1 yd" -- would result in a call to this function with --  iparm = 3 (parms[iparm] = "2", just after the first unit) --  total = 1 (number of yards) --  in_unit_table = (unit table for "yd") -- Return true, iparm, unit where --  iparm = index just after the composite units (7 in above example) --  unit = composite unit table holding all input units, -- or return true if no composite unit is present in parms, -- or return false, t where t is an error message table. local default, subinfo local composite_units, count = { in_unit_table }, 1 local fixups = {} local subunit = in_unit_table while subunit.subdivs do -- subdivs is nil or a table of allowed subdivisions local subcode = strip(parms[iparm+1]) local subdiv = subunit.subdivs[subcode] if not subdiv then break end local success success, subunit = lookup(subcode, parms.opt_sp_us, 'no_combination') if not success then return false, subunit end -- should never occur success, subinfo = extract_number(parms, parms[iparm]) if not success then return false, subinfo end iparm = iparm + 2 subunit.inout = 'in' subunit.valinfo = { subinfo } -- Recalculate total as a number of subdivisions. -- subdiv[1] = number of subdivisions per previous unit (integer > 1). total = total * subdiv[1] + subinfo.value if not default then -- set by the first subdiv with a default defined default = subdiv.default end count = count + 1 composite_units[count] = subunit if subdiv.unit or subdiv.name then fixups[count] = { unit = subdiv.unit, name = subdiv.name, valinfo = subunit.valinfo } end end if count == 1 then return true -- no error and no composite unit end for i, fixup in pairs(fixups) do		local unit = fixup.unit local name = fixup.name if not unit or (count > 2 and name) then composite_units[i].fixed_name = name else local success, alternate = lookup(unit, parms.opt_sp_us, 'no_combination') if not success then return false, alternate end -- should never occur alternate.inout = 'in' alternate.valinfo = fixup.valinfo composite_units[i] = alternate end end return true, iparm, { utype = in_unit_table.utype, scale = subunit.scale, -- scale of last (least significant) unit valinfo = { { value = total, clean = subinfo.clean, denominator = subinfo.denominator } }, composite = composite_units, default = default or in_unit_table.default } end

local function translate_parms(parms, kv_pairs) -- Update fields in parms by translating each key:value in kv_pairs to terms -- used by this module (may involve translating from local language to English). -- Also, checks are performed which may display warnings, if enabled. -- Return true if successful or return false, t where t is an error message table. if kv_pairs.adj and kv_pairs.sing then -- For en.wiki (before translation), warn if attempt to use adj and sing -- as the latter is a deprecated alias for the former. if kv_pairs.adj ~= kv_pairs.sing and kv_pairs.sing ~= '' then add_warning(parms, 1, 'cvt_unknown_option', 'sing=' .. kv_pairs.sing) end kv_pairs.sing = nil end for loc_name, loc_value in pairs(kv_pairs) do		local en_name = text_code.en_option_name[loc_name] if en_name then local en_value if en_name == 'frac' or en_name == 'sigfig' then if loc_value == '' then add_warning(parms, 2, 'cvt_empty_option', loc_name) else local minimum local number, is_integer = get_number(loc_value) if en_name == 'frac' then minimum = 2 if number and number < 0 then parms.opt_fraction_horizontal = true number = -number end else minimum = 1 end if number and is_integer and number >= minimum then en_value = number else add_warning(parms, 1, (en_name == 'frac' and 'cvt_bad_frac' or 'cvt_bad_sigfig'), loc_value) end end else en_value = text_code.en_option_value[en_name][loc_value] if en_value == nil then if loc_value == '' then add_warning(parms, 2, 'cvt_empty_option', loc_name) else -- loc_value can no longer be nil here (at one time, that could occur						-- with aliases like |sing=off|adj=on), but am retaining safety check. local text = loc_value and (loc_name .. '=' .. loc_value) or loc_name add_warning(parms, 1, 'cvt_unknown_option', text) end elseif en_value == '' then en_value = nil -- an ignored option like adj=off elseif type(en_value) == 'string' and en_value:sub(1, 4) == 'opt_' then for _, v in ipairs(split(en_value, ',')) do						parms[v] = true end en_value = nil end end parms[en_name] = en_value else add_warning(parms, 1, 'cvt_unknown_option', loc_name .. '=' .. loc_value) end end if parms.adj then if parms.adj:sub(1, 2) == 'ri' then -- It is known that adj is 'riN' where N is a single digit, so precision is valid. -- Only a single en digit is accepted. parms.input_precision = tonumber(parms.adj:sub(-1)) parms.adj = nil end end local cfg_abbr = config.abbr if cfg_abbr then if cfg_abbr == 'on always' then parms.abbr = 'on' elseif cfg_abbr == 'on default' then if parms.abbr == nil then parms.abbr = 'on' end end end if parms.abbr then parms.abbr_org = parms.abbr -- original abbr that was set, before any flip elseif parms.opt_hand_hh then parms.abbr_org = 'on' parms.abbr = 'on' else parms.abbr = 'out' -- default is to abbreviate output only (use symbol, not name) end if parms.opt_flip then local function swap_in_out(option) local value = parms[option] if value == 'in' then parms[option] = 'out' elseif value == 'out' then parms[option] = 'in' end end swap_in_out('abbr') swap_in_out('lk') if parms.opt_spell_in and not parms.opt_spell_out then -- For simplicity, and because it does not appear to be needed, -- user cannot set an option to spell the output only. parms.opt_spell_in = nil parms.opt_spell_out = true end end if parms.opt_spell_upper then parms.spell_upper = parms.opt_flip and 'out' or 'in' end if parms.opt_table or parms.opt_tablecen then if parms.abbr_org == nil and parms.lk == nil then parms.opt_values = true end local align = format('align="%s"', parms.opt_table and 'right' or 'center') parms.table_joins = { align .. '|', '\n|' .. align .. '|' }	end if parms.opt_lang_en then from_en_table = nil end return true end

local function get_values(parms) -- If successful, update parms and return true, v, i where --  v = table of input values --  i = index to next entry in parms after those processed here -- or return false, t where t is an error message table. local ranges = text_code.ranges local valinfo = collection -- numbered table of input values local range = collection -- numbered table of range items (having, for example, 2 range items requires 3 input values) local had_nocomma -- true if removed "nocomma" kludge from second parameter (like "tonocomma") local parm2 = strip(parms[2]) if parm2 and parm2:sub(-7, -1) == 'nocomma' then parms[2] = strip(parm2:sub(1, -8)) parms.opt_nocomma = true had_nocomma = true end local function extractor(i) -- If the parameter is not a value, try unpacking it as a range ("1-23" for "1 to 23"). -- However, "-1-2/3" is a negative fraction (-1⅔), so it must be extracted first. -- Unpacked items are inserted into the parms table. local valstr = strip(parms[i]) -- trim so any '-' as a negative sign will be at start local success, result = extract_number(parms, valstr, i > 1) if not success and valstr and i < 20 then -- check i to limit abuse for _, sep in ipairs(ranges.words) do				local start, stop = valstr:find(sep, 2, true) -- start at 2 to skip any negative sign for range '-' if start then parms[i] = valstr:sub(stop + 1) table.insert(parms, i, sep) table.insert(parms, i, valstr:sub(1, start - 1)) return extractor(i) -- this allows combinations like "1 x 2 to 3 x 4" end end end return success, result end local i = 1 local is_change while true do		local success, info = extractor(i) -- need to set parms.opt_nocomma before calling this if not success then return false, info end i = i + 1 if is_change then info.is_change = true -- value is after "±" and so is a change (significant for range like 5 ±) is_change = nil end valinfo:add(info) local next = strip(parms[i]) local range_item = ranges.types[next] or ranges.types[ranges.aliases[next]] if not range_item then break end i = i + 1 range:add(range_item) if type(range_item) == 'table' then parms.is_range_x = range_item.is_range_x is_change = range_item.is_range_change end end if range.n > 0 then if range.n > 30 then -- limit abuse, although 4 is a more likely upper limit return false, { 'cvt_invalid_num' } -- misleading message but it will do		end parms.range = range elseif had_nocomma then return false, { 'cvt_unknown', parm2 } end return true, valinfo, i end

local function simple_get_values(parms) -- If input is like "valid_value valid_unit", -- return true, v, 3, in_unit, in_unit_table -- (as for get_values, but with a unit name and table for a valid unit;	-- 3 = index in parms of whatever follows valid_unit, if anything). -- The valid_value is not negative and does not use a fraction, and -- no options requiring further processing of the input are used. -- Otherwise, return nothing and caller will reparse the input. -- Testing shows this function is successful for 96% of converts in articles, -- and that on average it speeds up converts by 8%. if parms.input_precision or parms.opt_spell_in then return end local clean = to_en(strip(parms[1] or '')) if #clean > 10 or not clean:match('^[0-9.]+$') then return end local value = tonumber(clean) if not value then return end local info = { value = value, altvalue = value, singular = (value == 1), clean = clean, show = with_separator(parms, clean), }	local in_unit = strip(parms[2]) local success, in_unit_table = lookup(in_unit, parms.opt_sp_us, 'no_combination') if not success then return end return true, { info }, 3, in_unit, in_unit_table end

local function get_parms(pframe) -- If successful, return true, parms, unit where --  parms is a table of all arguments passed to the template --       converted to named arguments, and --  unit is the input unit table; -- or return false, t where t is an error message table. -- The returned input unit table may be for a fake unit using the specified -- unit code as the symbol and name, and with bad_mcode = message code table. -- MediaWiki removes leading and trailing whitespace from the values of -- named arguments. However, the values of numbered arguments include any -- whitespace entered in the template, and whitespace is used by some -- parameters (example: the numbered parameters associated with "disp=x"). local parms = {} -- arguments passed to template, after translation local kv_pairs = {} -- table of input key:value pairs where key is a name; needed because cannot iterate parms and add new fields to it	for k, v in pairs(pframe.args) do		if type(k) == 'number' or k == 'test' then  -- parameter "test" is reserved for testing and is not translated parms[k] = v		else kv_pairs[k] = v		end end local success, msg = translate_parms(parms, kv_pairs) if not success then return false, msg end local success, valinfo, i, in_unit, in_unit_table = simple_get_values(parms) if not success then success, valinfo, i = get_values(parms) if not success then return false, valinfo end in_unit = strip(parms[i]) i = i + 1 success, in_unit_table = lookup(in_unit, parms.opt_sp_us, 'no_combination') if not success then if in_unit == nil then in_unit = '' end if parms.opt_ignore_error then -- display given unit code with no error (for use with ) in_unit_table = nil end in_unit_table = setmetatable({ symbol = in_unit, name2 = in_unit, utype = "length", scale = 1, bad_mcode = in_unit_table, default = "m" }, unit_mt) end end if parms.test == 'msg' then -- Am testing the messages produced when no output unit is specified, and -- the input unit has a missing or invalid default. -- Set two units for testing that. -- LATER: Remove this code. if in_unit == 'chain' then in_unit_table.default = nil -- no default elseif in_unit == 'rd' then in_unit_table.default = "ft!X!m"  -- an invalid expression end end in_unit_table.valinfo = valinfo in_unit_table.inout = 'in' -- this is an input unit if not parms.range then local success, inext, composite_unit = get_composite(parms, i, valinfo[1].value, in_unit_table) if not success then return false, inext end if composite_unit then in_unit_table = composite_unit i = inext end end if in_unit_table.builtin == 'mach' then -- As with old template, a number following Mach as the input unit is the altitude, -- and there is no way to specify an altitude for the output unit. -- Could put more code in this function to get any output unit and check for -- an altitude following that unit. local success, info = extract_number(parms, parms[i], false, true) if success then i = i + 1 in_unit_table.altitude = info.value end end local next = strip(parms[i]) i = i + 1 local precision, is_bad_precision local function set_precision(text) local number, is_integer = get_number(text) if number then if is_integer then precision = number else precision = text is_bad_precision = true end return true -- text was used for precision, good or bad end end if not set_precision(next) then parms.out_unit = next if set_precision(strip(parms[i])) then i = i + 1 end end if parms.opt_adj_mid then parms.opt_adjectival = true next = parms[i] i = i + 1 if next then -- mid-text words if next:sub(1, 1) == '-' then parms.mid = next else parms.mid = ' ' .. next end end end if parms.opt_one_preunit then parms[parms.opt_flip and 'preunit2' or 'preunit1'] = preunits(1, parms[i]) i = i + 1 end if parms.disp == 'x' then -- Following is reasonably compatible with the old template. local first = parms[i] or '' local second = parms[i+1] or '' i = i + 2 if strip(first) == '' then -- user can enter '&#32;' rather than ' ' to avoid the default first = ' [ ' .. first second = ' ]' .. second end parms.joins = { first, second } elseif parms.opt_two_preunits then local p1, p2 = preunits(2, parms[i], parms[i+1]) i = i + 2 if parms.preunit1 then -- To simplify documentation, allow unlikely use of adj=pre with disp=preunit -- (however, an output unit must be specified with adj=pre and with disp=preunit). parms.preunit1 = parms.preunit1 .. p1			parms.preunit2 = p2		else parms.preunit1, parms.preunit2 = p1, p2		end end if precision == nil then if set_precision(strip(parms[i])) then i = i + 1 end end if is_bad_precision then add_warning(parms, 1, 'cvt_bad_prec', precision) else parms.precision = precision end return true, parms, in_unit_table end

local function record_default_precision(parms, out_current, precision) -- If necessary, adjust parameters and return a possibly adjusted precision. -- When converting a range of values where a default precision is required, -- that default is calculated for each value because the result sometimes -- depends on the precise input and output values. This function may cause -- the entire convert process to be repeated in order to ensure that the -- same default precision is used for each individual convert. -- If that were not done, a range like 1000 to 1000.4 may give poor results -- because the first output could be heavily rounded, while the second is not. -- For range 1000.4 to 1000, this function can give the second convert the -- same default precision that was used for the first. if not parms.opt_round_each then local maxdef = out_current.max_default_precision if maxdef then if maxdef < precision then parms.do_convert_again = true out_current.max_default_precision = precision else precision = out_current.max_default_precision end else out_current.max_default_precision = precision end end return precision end

local function default_precision(parms, invalue, inclean, denominator, outvalue, in_current, out_current, extra) -- Return a default value for precision (an integer like 2, 0, -2). -- If denominator is not nil, it is the value of the denominator in inclean. -- Code follows procedures used in old template. local fudge = 1e-14 -- 0 adds this, so we do too local prec, minprec, adjust local utype = out_current.utype local subunit_ignore_trailing_zero local subunit_more_precision -- kludge for "in" used in input like "|2|ft|6|in" local composite = in_current.composite if composite then subunit_ignore_trailing_zero = true -- input "|2|st|10|lb" has precision 0, not -1 if composite[#composite].exception == 'subunit_more_precision' then subunit_more_precision = true -- do not use standard precision with input like "|2|ft|6|in" end end if denominator and denominator > 0 then prec = math.max(log10(denominator), 1) else -- Count digits after decimal mark, handling cases like '12.345e6'. local exponent local integer, dot, decimals, expstr = inclean:match('^(%d*)(%.?)(%d*)(.*)') local e = expstr:sub(1, 1) if e == 'e' or e == 'E' then exponent = tonumber(expstr:sub(2)) end if dot == '' then prec = subunit_ignore_trailing_zero and 0 or -integer:match('0*$'):len else prec = #decimals end if exponent then -- So '1230' and '1.23e3' both give prec = -1, and '0.00123' and '1.23e-3' give 5. prec = prec - exponent end end if in_current.istemperature and out_current.istemperature then -- Converting between common temperatures (°C, °F, °R, K); not keVT, MK. -- Kelvin value can be almost zero, or small but negative due to precision problems. -- Also, an input value like -300 C (below absolute zero) gives negative kelvins. -- Calculate minimum precision from absolute value. adjust = 0 local kelvin = abs((invalue - in_current.offset) * in_current.scale) if kelvin < 1e-8 then -- assume nonzero due to input or calculation precision problem minprec = 2 else minprec = 2 - floor(log10(kelvin) + fudge) -- 3 sigfigs in kelvin end else if invalue == 0 or outvalue <= 0 then -- We are never called with a negative outvalue, but it might be zero. -- This is special-cased to avoid calculation exceptions. return record_default_precision(parms, out_current, 0) end if out_current.exception == 'integer_more_precision' and floor(invalue) == invalue then -- With certain output units that sometimes give poor results -- with default rounding, use more precision when the input -- value is equal to an integer. An example of a poor result -- is when input 50 gives a smaller output than input 49.5. -- Experiment shows this helps, but it does not eliminate all -- surprises because it is not clear whether "50" should be -- interpreted as "from 45 to 55" or "from 49.5 to 50.5". adjust = -log10(in_current.scale) elseif subunit_more_precision then -- Conversion like "6 ft" (where subunit is "in") -- has a non-standard adjust value, to give more output precision. adjust = log10(out_current.scale) + 2 else adjust = log10(abs(invalue / outvalue)) end adjust = adjust + log10(2) -- Ensure that the output has at least two significant figures. minprec = 1 - floor(log10(outvalue) + fudge) end if extra then adjust = extra.adjust or adjust minprec = extra.minprec or minprec end return record_default_precision(parms, out_current, math.max(floor(prec + adjust), minprec)) end

local function convert(parms, invalue, info, in_current, out_current) -- Convert given input value from one unit to another. -- Return output_value (a number) if a simple convert, or	-- return f, t where --  f = true, t = table of information with results, or --  f = false, t = error message table. local inscale = in_current.scale local outscale = out_current.scale if not in_current.iscomplex and not out_current.iscomplex then return invalue * (inscale / outscale) -- minimize overhead for most common case end if in_current.invert or out_current.invert then -- Inverted units, such as inverse length, inverse time, or -- fuel efficiency. Built-in units do not have invert set. if (in_current.invert or 1) * (out_current.invert or 1) < 0 then return 1 / (invalue * inscale * outscale) end return invalue * (inscale / outscale) elseif in_current.offset then -- Temperature (there are no built-ins for this type of unit). if info.is_change then return invalue * (inscale / outscale) end return (invalue - in_current.offset) * (inscale / outscale) + out_current.offset else -- Built-in unit. local in_builtin = in_current.builtin local out_builtin = out_current.builtin if in_builtin and out_builtin then if in_builtin == out_builtin then return invalue end -- There are no cases (yet) where need to convert from one -- built-in unit to another, so this should never occur. return false, { 'cvt_bug_convert' } end if in_builtin == 'mach' or out_builtin == 'mach' then local adjust if in_builtin == 'mach' then inscale = speed_of_sound(in_current.altitude) adjust = outscale / 0.1 else outscale = speed_of_sound(out_current.altitude) adjust = 0.1 / inscale end return true, { outvalue = invalue * (inscale / outscale), adjust = log10(adjust) + log10(2), }		elseif in_builtin == 'hand' then -- 1 hand = 4 inches; 1.2 hands = 6 inches. -- Decimals of a hand are only defined for the first digit, and -- the first fractional digit should be a number of inches (1, 2 or 3). -- However, this code interprets the entire fractional part as the number -- of inches / 10 (so 1.75 inches would be 0.175 hands). -- A value like 12.3 hands is exactly 12*4 + 3 inches; base default precision on that. local integer, fracpart = math.modf(invalue) local inch_value = 4 * integer + 10 * fracpart -- equivalent number of inches local factor = inscale / outscale if factor == 4 then -- Am converting to inches: show exact result, and use "inches" not "in" by default. if parms.abbr_org == nil then out_current.usename = true end local show = format('%g', abs(inch_value)) -- show and clean are unsigned if not show:find('e', 1, true) then return true, { invalue = inch_value, outvalue = inch_value, clean = show, show = show, }				end end local outvalue = (integer + 2.5 * fracpart) * factor local fracstr = info.clean:match('%.(.*)') or '' local fmt if fracstr == '' then fmt = '%.0f' else fmt = '%.' .. format('%d', #fracstr - 1) .. 'f'			end return true, { invalue = inch_value, clean = format(fmt, inch_value), outvalue = outvalue, minprec = 0, }		end end return false, { 'cvt_bug_convert' } -- should never occur end

local cvt_to_hand

local function cvtround(parms, info, in_current, out_current) -- Return true, t where t is a table with the conversion results; fields: --  show = rounded, formatted string with the result of converting value in info, --     using the rounding specified in parms. --  singular = true if result is positive, and (after rounding) --     is "1", or like "1.00"; --  (and more fields shown below, and a calculated 'absvalue' field). -- or return true, nil if no value specified; -- or return false, t where t is an error message table. -- Input info.clean uses en digits (it has been translated, if necessary). -- Output show uses en or non-en digits as appropriate, or can be spelled. local invalue if info then invalue = info.value if in_current.builtin == 'hand' then invalue = info.altvalue end end if invalue == nil or invalue == '' then return true, nil end if out_current.builtin == 'hand' then return cvt_to_hand(parms, info, in_current, out_current) end local outvalue, extra = convert(parms, invalue, info, in_current, out_current) if extra then if not outvalue then return false, extra end invalue = extra.invalue or invalue outvalue = extra.outvalue end if not valid_number(outvalue) then return false, { 'cvt_invalid_num' } end local isnegative if outvalue < 0 then isnegative = true outvalue = -outvalue end local numerator, precision, success, show, exponent local denominator = out_current.frac if denominator then show = fraction_table(outvalue, denominator) else precision = parms.precision if not precision then local sigfig = parms.sigfig if sigfig then show, exponent = make_sigfig(outvalue, sigfig) elseif parms.opt_round5 or parms.opt_round25 then local n = parms.opt_round5 and 5 or 25 show = format('%.0f', floor((outvalue / n) + 0.5) * n)			else local inclean = info.clean if extra then inclean = extra.clean or inclean show = extra.show end if not show then precision = default_precision(parms, invalue, inclean, info.denominator, outvalue, in_current, out_current, extra) end end end end if precision then if precision >= 0 then local fudge if precision <= 8 then -- Add a fudge to handle common cases of bad rounding due to inability -- to precisely represent some values. This makes the following work: -- -100.1 C and 5555000 um. -- Old template uses #expr round, which invokes PHP round. -- LATER: Investigate how PHP round works. fudge = 2e-14 else fudge = 0 end local fmt = '%.' .. format('%d', precision) .. 'f'			local success success, show = pcall(format, fmt, outvalue + fudge) if not success then return false, { 'cvt_big_prec', tostring(precision) } end else precision = -precision -- #digits to zero (in addition to any digits after dot) local shift = 10 ^ precision show = format('%.0f', outvalue/shift) if show ~= '0' then exponent = #show + precision end end end local t = format_number(parms, show, exponent, isnegative) -- Set singular using match because on some systems 0.99999999999999999 is 1.0. t.singular = (type(show) == 'string' and (show == '1' or show:match('^1%.0*$') ~= nil) and not isnegative) t.fraction_table = (type(show) == 'table') and show or nil t.raw_absvalue = outvalue -- absolute value before rounding return true, setmetatable(t, {		__index = function (self, key)			if key == 'absvalue' then				-- Calculate absolute value after rounding, if needed.				local clean, exponent = rawget(self, 'clean'), rawget(self, 'exponent')				local value = tonumber(clean) -- absolute value (any negative sign has been ignored)				if exponent then					value = value * 10^exponent				end				rawset(self, key, value)				return value			end		end }) end

function cvt_to_hand(parms, info, in_current, out_current) -- Convert input to hands, inches. -- Return true, t where t is a table with the conversion results; -- or return false, t where t is an error message table. if parms.abbr_org == nil then out_current.usename = true -- default is to show name not symbol end local precision = parms.precision local frac = out_current.frac if not frac and precision and precision > 1 then frac = (precision == 2) and 2 or 4 end local out_next = out_current.out_next if out_next then -- Use magic knowledge to determine whether the next unit is inches without requiring i18n. -- The following ensures that when the output combination "hand in" is used, the inches -- value is rounded to match the hands value. Also, displaying say "61½" instead of 61.5 -- is better as 61.5 implies the value is not 61.4. if out_next.exception == 'subunit_more_precision' then out_next.frac = frac end end -- Convert to inches; calculate hands from that. local dummy_unit_table = { scale = out_current.scale / 4, frac = frac } local success, outinfo = cvtround(parms, info, in_current, dummy_unit_table) if not success then return false, outinfo end local tfrac = outinfo.fraction_table local inches = outinfo.raw_absvalue if tfrac then inches = floor(inches) -- integer part only; fraction added later else inches = floor(inches + 0.5) -- a hands measurement never shows decimals of an inch end local hands, inches = divide(inches, 4) outinfo.absvalue = hands + inches/4 -- supposed to be the absolute rounded value, but this is close enough local inchstr = tostring(inches) -- '0', '1', '2' or '3' if precision and precision <= 0 then -- using negative or 0 for precision rounds to nearest hand hands = floor(outinfo.raw_absvalue/4 + 0.5) inchstr = '' elseif tfrac then -- Always show an integer before fraction (like "15.0½") because "15½" means 15-and-a-half hands. inchstr = numdot .. format_fraction(parms, 'out', false, inchstr, tfrac.numstr, tfrac.denstr) else inchstr = numdot .. from_en(inchstr) end outinfo.show = outinfo.sign .. with_separator(parms, format('%.0f', hands)) .. inchstr return true, outinfo end

local function evaluate_condition(value, condition) -- Return true or false from applying a conditional expression to value, -- or throw an error if invalid. -- A very limited set of expressions is supported: --   v < 9 --   v * 9 < 9 -- where --   'v' is replaced with value --   9 is any number (as defined by Lua tonumber) --     only en digits are accepted --   '<' can also be '<=' or '>' or '>=' -- In addition, the following form is supported: --   LHS and RHS -- where --   LHS, RHS = any of above expressions. local function compare(value, text) local arithop, factor, compop, limit = text:match('^%s*v%s*([*]?)(.-)([<>]=?)(.*)$') if arithop == nil then error('Invalid default expression', 0) elseif arithop == '*' then factor = tonumber(factor) if factor == nil then error('Invalid default expression', 0) end value = value * factor end limit = tonumber(limit) if limit == nil then error('Invalid default expression', 0) end if compop == '<' then return value < limit elseif compop == '<=' then return value <= limit elseif compop == '>' then return value > limit elseif compop == '>=' then return value >= limit end error('Invalid default expression', 0) -- should not occur end local lhs, rhs = condition:match('^(.-%W)and(%W.*)') if lhs == nil then return compare(value, condition) end return compare(value, lhs) and compare(value, rhs) end

local function get_default(value, unit_table) -- Return true, s where s = name of unit's default output unit, -- or return false, t where t is an error message table. -- Some units have a default that depends on the input value -- (the first value if a range of values is used). -- If '!' is in the default, the first bang-delimited field is an -- expression that uses 'v' to represent the input value. -- Example: 'v < 120 ! small ! big ! suffix' (suffix is optional) -- evaluates 'v < 120' as a boolean with result -- 'smallsuffix' if (value < 120), or 'bigsuffix' otherwise. -- Input must use en digits and '.' decimal mark. local default = default_exceptions[unit_table.defkey or unit_table.symbol] or unit_table.default if not default then return false, { 'cvt_no_default', unit_table.symbol } end if default:find('!', 1, true) == nil then return true, default end local t = split(default, '!') if #t == 3 or #t == 4 then local success, result = pcall(evaluate_condition, value, t[1]) if success then default = result and t[2] or t[3] if #t == 4 then default = default .. t[4] end return true, default end end return false, { 'cvt_bad_default', unit_table.symbol } end

local linked_pages -- to record linked pages so will not link to the same page more than once

local function make_link(link, id, link_key) -- Return wikilink "id", possibly abbreviated as in examples: --  mile  --> mile --  miles --> miles -- However, just id is returned if: -- * no link given (so caller does not need to check if a link was defined); or -- * link has previously been used during the current convert (to avoid overlinking). -- Linking with a unit uses the unit table as the link key, which fails to detect -- overlinking for conversions like the following (each links "mile" twice): --  1 impgal/mi --  1 l/km link_key = link_key or link -- use key if given (the key, but not the link, may be known when need to cancel a link record) if not link or link == '' or linked_pages[link_key] then return id	end linked_pages[link_key] = true -- Following only works for language en, but it should be safe on other wikis, -- and overhead of doing it generally does not seem worthwhile. local l = link:sub(1, 1):lower .. link:sub(2) if link == id or l == id then return  .. id ..  elseif link .. 's' == id or l .. 's' == id then return '' .. id:sub(1, -2) .. 's' else return  .. id ..  end end

local function variable_name(clean, unit_table) -- For sl.wiki (Slovenian Wikipedia), a unit name depends on the value. -- Parameter clean is the unsigned rounded value in en digits, as a string. -- Value            Source    Example for "m" -- integer 1:       name1     meter  (also is the name of the unit) -- integer 2:       var{1}    metra -- integer 3 and 4: var{2}    metri -- integer else:    var{3}    metrov (0 and 5 or more) -- real/fraction:   var{4}    metra -- var{i} means the i'th field in unit_table.varname if it exists and has -- an i'th field, otherwise name2. -- Fields are separated with "!" and are not empty. -- A field for a unit using an SI prefix has the prefix name inserted, -- replacing '#' if found, or before the field otherwise. local vname if clean == '1' then vname = unit_table.name1 elseif unit_table.varname then local i		if clean == '2' then i = 1 elseif clean == '3' or clean == '4' then i = 2 elseif clean:find('.', 1, true) then i = 4 else i = 3 end vname = split(unit_table.varname, '!')[i] end if vname then local si_name = rawget(unit_table, 'si_name') or '' local pos = vname:find('#', 1, true) if pos then vname = vname:sub(1, pos - 1) .. si_name .. vname:sub(pos + 1) else vname = si_name .. vname end return vname end return unit_table.name2 end

local function linked_id(unit_table, key_id, want_link, clean) -- Return final unit id (symbol or name), optionally with a wikilink, -- and update unit_table.sep if required. -- key_id is one of: 'symbol', 'sym_us', 'name1', 'name1_us', 'name2', 'name2_us'. local abbr_on = (key_id == 'symbol' or key_id == 'sym_us') if abbr_on and want_link then local symlink = rawget(unit_table, 'symlink') if symlink then return symlink -- for exceptions that have the linked symbol built-in end end local multiplier = rawget(unit_table, 'multiplier') local per = unit_table.per if per then local unit1 = per[1] -- top unit_table, or nil local unit2 = per[2] -- bottom unit_table if abbr_on then if not unit1 then unit_table.sep = '' -- no separator in "$2/acre" end if not want_link then local symbol = unit_table.symbol_raw if symbol then return symbol -- for exceptions that have the symbol built-in end end end local key_id2 -- unit2 is always singular if key_id == 'name2' then key_id2 = 'name1' elseif key_id == 'name2_us' then key_id2 = 'name1_us' else key_id2 = key_id end local result if abbr_on then result = '/' elseif unit1 then result = ' ' .. per_word .. ' '		else result = per_word .. ' '		end if want_link and unit_table.link then if abbr_on or not varname then result = (unit1 and unit1[key_id] or '') .. result .. unit2[key_id2] else result = (unit1 and variable_name(clean, unit1) or '') .. result .. variable_name('1', unit2) end return make_link(unit_table.link, result, unit_table) end if unit1 then result = linked_id(unit1, key_id, want_link, clean) .. result end return result .. linked_id(unit2, key_id2, want_link, '1') end if multiplier then -- A multiplier (like "100" in "100km") forces the unit to be plural. multiplier = from_en(multiplier) if abbr_on then multiplier = multiplier .. ' '		else multiplier = multiplier .. ' '			if key_id == 'name1' then key_id = 'name2' elseif key_id == 'name1_us' then key_id = 'name2_us' end end else multiplier = '' end local id = unit_table.fixed_name or ((varname and not abbr_on) and variable_name(clean, unit_table) or unit_table[key_id]) if want_link then local link = link_exceptions[unit_table.linkey or unit_table.symbol] or unit_table.link if link then local before = '' local i = unit_table.customary if i == 1 and unit_table.sp_us then i = 2 -- show "U.S." not "US" end if i == 3 and abbr_on then i = 4 -- abbreviate "imperial" to "imp" end local customary = text_code.customary_units[i] if customary then -- LATER: This works for language en only, but it's esoteric so ignore for now. local pertext if id:sub(1, 1) == '/' then -- Want unit "/USgal" to display as "/U.S. gal", not "U.S. /gal". pertext = '/' id = id:sub(2) elseif id:sub(1, 4) == 'per ' then -- Similarly want "per U.S. gallon", not "U.S. per gallon" (but in practice this is unlikely to be used). pertext = 'per ' id = id:sub(5) else pertext = '' end -- Omit any "US"/"U.S."/"imp"/"imperial" from start of id since that will be inserted. local removes = (i < 3) and { 'US ', 'US ', 'U.S. ', 'U.S. ' } or { 'imp ', 'imp ', 'imperial ' } for _, prefix in ipairs(removes) do					local plen = #prefix if id:sub(1, plen) == prefix then id = id:sub(plen + 1) break end end before = pertext .. make_link(customary.link, customary[1]) .. ' '			end id = before .. make_link(link, id, unit_table) end end return multiplier .. id end

local function make_id(parms, which, unit_table) -- Return id, f where --  id = unit name or symbol, possibly modified --  f = true if id is a name, or false if id is a symbol -- using 1st or 2nd values (which), and for 'in' or 'out' (unit_table.inout). -- Result is '' if no symbol/name is to be used. -- In addition, set unit_table.sep = ' ' or ' ' or '' -- (the separator that caller will normally insert before the id). if parms.opt_values then unit_table.sep = '' return '' end local inout = unit_table.inout local info = unit_table.valinfo[which] local abbr_org = parms.abbr_org local adjectival = parms.opt_adjectival local disp = parms.disp local lk = parms.lk	local want_link = (lk == 'on' or lk == inout) local usename = unit_table.usename local singular = info.singular if usename then -- Old template does something like this. if want_link then -- A linked unit uses the standard singular. else -- Set non-standard singular. local flipped = parms.opt_flip if inout == 'in' then if not adjectival and (abbr_org == 'out' or flipped) then local value = info.value singular = (0 < value and value < 1.0001) end else if (abbr_org == 'on') or				(not flipped and (abbr_org == nil or abbr_org == 'out')) or				(flipped and abbr_org == 'in') then singular = (info.absvalue < 1.0001 and								not info.is_scientific) end end end end local want_name if usename then want_name = true else if abbr_org == nil then if disp == 'br' or disp == 'or' or disp == 'slash' then want_name = true end if unit_table.usesymbol then want_name = false end end if want_name == nil then local abbr = parms.abbr if abbr == 'on' or abbr == inout or (abbr == 'mos' and inout == 'out') then want_name = false else want_name = true end end end local key if want_name then if lk == nil and unit_table.builtin == 'hand' then want_link = true end if parms.opt_use_nbsp then unit_table.sep = ' ' else unit_table.sep = ' ' end if parms.opt_singular then local value if inout == 'in' then value = info.value else value = info.absvalue end if value then -- some unusual units do not always set value field value = abs(value) singular = (0 < value and value < 1.0001) end end if unit_table.engscale or parms.is_range_x then -- engscale: so "|1|e3kg" gives "1 thousand kilograms" (plural) -- is_range_x: so "|0.5|x|0.9|mi" gives "0.5 by 0.9 miles" (plural) singular = false end key = (adjectival or singular) and 'name1' or 'name2' if unit_table.sp_us then key = key .. '_us' end else if unit_table.builtin == 'hand' then if parms.opt_hand_hh then unit_table.symbol = 'hh' -- LATER: might want i18n applied to this end end unit_table.sep = ' ' key = unit_table.sp_us and 'sym_us' or 'symbol' end return linked_id(unit_table, key, want_link, info.clean), want_name end

local function decorate_value(parms, unit_table, which) -- If needed, update unit_table so values will be shown with extra information. -- For consistency with the old template (but different from fmtpower), -- the style to display powers of 10 includes "display:none" to allow some -- browsers to copy, for example, "10³" as "10^3", rather than as "103". local info local engscale = unit_table.engscale local prefix = unit_table.vprefix if engscale or prefix then info = unit_table.valinfo[which] if info.decorated then return -- do not redecorate if repeating convert end info.decorated = true end if engscale then local inout = unit_table.inout local abbr = parms.abbr if abbr == 'on' or abbr == inout then info.show = info.show .. ' × ' ..				from_en('10') .. ' ^ ' .. from_en(tostring(engscale.exponent)) .. ' '		else local number_id local lk = parms.lk			if lk == 'on' or lk == inout then number_id = make_link(engscale.link, engscale[1]) else number_id = engscale[1] end -- WP:NUMERAL recommends " " in values like "12 million". info.show = info.show .. (parms.opt_adjectival and '-' or ' ') .. number_id end end if prefix then info.show = prefix .. info.show end end

local function process_input(parms, in_current) -- Processing required once per conversion. -- Return block of text to represent input (value/unit). if parms.opt_output_only or parms.opt_output_number_only or parms.opt_output_unit_only then parms.joins = { ,  } return '' end local first_unit local composite = in_current.composite -- nil or table of units if composite then first_unit = composite[1] else first_unit = in_current end local id1, want_name = make_id(parms, 1, first_unit) local sep = first_unit.sep -- separator between value and unit, set by make_id local preunit = parms.preunit1 if preunit then sep = '' -- any separator is included in preunit else preunit = '' end if parms.opt_input_unit_only then parms.joins = { ,  } if composite then local parts = { id1 } for i, unit in ipairs(composite) do				if i > 1 then table.insert(parts, (make_id(parms, 1, unit))) end end id1 = table.concat(parts, ' ') end if want_name and parms.opt_adjectival then return preunit .. hyphenated(id1) end return preunit .. id1 end local disp_joins = text_code.disp_joins local abbr = parms.abbr local disp = parms.disp if disp == nil then -- special case for the most common setting parms.joins = disp_joins['b'] elseif disp ~= 'x' then -- Old template does this. if disp == 'slash' then if parms.abbr_org == nil then disp = 'slash-nbsp' elseif abbr == 'in' or abbr == 'out' then disp = 'slash-sp' else disp = 'slash-nosp' end elseif disp == 'sqbr' then if abbr == 'on' then disp = 'sqbr-nbsp' else disp = 'sqbr-sp' end end parms.joins = disp_joins[disp] or disp_joins['b'] end if parms.opt_also_symbol and not composite then local join1 = parms.joins[1] if join1 == ' (' or join1 == ' [' then			parms.joins = { join1 .. first_unit[first_unit.sp_us and 'sym_us' or 'symbol'] .. ', ', parms.joins[2] }		end	end	if in_current.builtin == 'mach' then		local prefix = id1 .. ' '		local range = parms.range		local valinfo = first_unit.valinfo		local result = prefix .. valinfo[1].show		if range then			-- For simplicity and because more not needed, handle one range item only.			local prefix2 = make_id(parms, 2, first_unit) .. ' '			result = range_text(range[1], want_name, parms, result, prefix2 .. valinfo[2].show)		end		return preunit .. result	end	if composite then		-- Simplify: assume there is no range, and no decoration.		local mid = 		local sep1 = ' '		local sep2 = ' '		if parms.opt_adjectival then			if not parms.opt_flip then				mid = parms.mid or 			end			if want_name then				sep1 = '-'				sep2 = '-'			end		end		local parts = { first_unit.valinfo[1].show .. sep1 .. id1 }		for i, unit in ipairs(composite) do			if i > 1 then				table.insert(parts, unit.valinfo[1].show .. sep1 .. (make_id(parms, 1, unit)))			end		end		return table.concat(parts, sep2) .. mid	end	local result, mos	local range = parms.range	if range then		mos = (abbr == 'mos')		if not (mos or (parms.is_range_x and not want_name)) then			linked_pages[first_unit] = nil -- so the second and only id will be linked, if wanted		end	end	local id = (range == nil) and id1 or make_id(parms, 2, first_unit)	local extra, was_hyphenated = hyphenated_maybe(parms, want_name, sep, id, 'in')	if mos and was_hyphenated then		mos = false  -- suppress repeat of unit in a range		if linked_pages[first_unit] then			linked_pages[first_unit] = nil			id = make_id(parms, 2, first_unit)			extra = hyphenated_maybe(parms, want_name, sep, id, 'in')		end	end	local valinfo = first_unit.valinfo	if range then		if range.n == 1 then			-- Like 1 x (one range item; two values).			-- Do what old template did.			local sep1 = first_unit.sep if mos then decorate_value(parms, in_current, 1) decorate_value(parms, in_current, 2) result = valinfo[1].show .. sep1 .. id1 elseif parms.is_range_x and not want_name then if abbr == 'in' or abbr == 'on' then decorate_value(parms, in_current, 1) end decorate_value(parms, in_current, 2) result = valinfo[1].show .. sep1 .. id1 else if abbr == 'in' or abbr == 'on' then decorate_value(parms, in_current, 1) end decorate_value(parms, in_current, 2) result = valinfo[1].show end result = range_text(range[1], want_name, parms, result, valinfo[2].show) else -- Like 1 x (two or more range items): simplify. decorate_value(parms, in_current, 1) result = valinfo[1].show for i = 1, range.n do				decorate_value(parms, in_current, i+1) result = range_text(range[i], want_name, parms, result, valinfo[i+1].show) end end else decorate_value(parms, first_unit, 1) result = valinfo[1].show end return result .. preunit .. extra end

local function process_one_output(parms, out_current) -- Processing required for each output unit. -- Return block of text to represent output (value/unit). local id1, want_name = make_id(parms, 1, out_current) local sep = out_current.sep -- set by make_id local preunit = parms.preunit2 if preunit then sep = '' -- any separator is included in preunit else preunit = '' end if parms.opt_output_unit_only then if want_name and parms.opt_adjectival then return preunit .. hyphenated(id1) end return preunit .. id1 end if out_current.builtin == 'mach' then local prefix = id1 .. ' '		local range = parms.range local valinfo = out_current.valinfo local result = prefix .. valinfo[1].show if range then -- For simplicity and because more not needed, handle one range item only. result = range_text(range[1], want_name, parms, result, prefix .. valinfo[2].show) end return preunit .. result end local result local range = parms.range if range then if not (parms.is_range_x and not want_name) then linked_pages[out_current] = nil -- so the second and only id will be linked, if wanted end end local id = (range == nil) and id1 or make_id(parms, 2, out_current) local extra = hyphenated_maybe(parms, want_name, sep, id, 'out') local valinfo = out_current.valinfo if range then if range.n == 1 then local sep1 = out_current.sep local abbr = parms.abbr if parms.is_range_x and not want_name then if abbr == 'out' or abbr == 'on' then decorate_value(parms, out_current, 1) end decorate_value(parms, out_current, 2) result = valinfo[1].show .. sep1 .. id1 else if abbr == 'out' or abbr == 'on' then decorate_value(parms, out_current, 1) end decorate_value(parms, out_current, 2) result = valinfo[1].show end result = range_text(range[1], want_name, parms, result, valinfo[2].show) else -- Like 1 x (two or more range items): simplify. decorate_value(parms, out_current, 1) result = valinfo[1].show for i = 1, range.n do				decorate_value(parms, out_current, i+1) result = range_text(range[i], want_name, parms, result, valinfo[i+1].show) end end else decorate_value(parms, out_current, 1) result = valinfo[1].show end if parms.opt_output_number_only then return result end return result .. preunit .. extra end

local function make_output_single(parms, in_unit_table, out_unit_table) -- Return true, item where item = wikitext of the conversion result -- for a single output (which is not a combination or a multiple); -- or return false, t where t is an error message table. out_unit_table.valinfo = collection local range = parms.range for i = 1, (range and (range.n + 1) or 1) do		local success, info = cvtround(parms, in_unit_table.valinfo[i], in_unit_table, out_unit_table) if not success then return false, info end out_unit_table.valinfo:add(info) end return true, process_one_output(parms, out_unit_table) end

local function make_output_multiple(parms, in_unit_table, out_unit_table) -- Return true, item where item = wikitext of the conversion result -- for an output which is a multiple (like 'ftin'); -- or return false, t where t is an error message table. local multiple = out_unit_table.multiple -- table of scaling factors (will not be nil) local combos = out_unit_table.combination -- table of unit tables (will not be nil) local abbr = parms.abbr local abbr_org = parms.abbr_org local disp = parms.disp local want_name = (abbr_org == nil and (disp == 'or' or disp == 'slash')) or						not (abbr == 'on' or abbr == 'out' or abbr == 'mos') local want_link = (parms.lk == 'on' or parms.lk == 'out') local mid = '' local sep1 = ' ' local sep2 = ' ' if parms.opt_adjectival then if parms.opt_flip then mid = parms.mid or '' end if want_name then sep1 = '-' sep2 = '-' end end local do_spell = parms.opt_spell_out parms.opt_spell_out = nil -- so the call to cvtround does not spell the value local function make_result(info, isfirst) local fmt, outvalue, sign local results = {} for i = 1, #combos do			local tfrac, thisvalue, strforce local out_current = combos[i] out_current.inout = 'out' local scale = multiple[i] if i == 1 then -- least significant unit ('in' from 'ftin') local decimals out_current.frac = out_unit_table.frac local success, outinfo = cvtround(parms, info, in_unit_table, out_current) if not success then return false, outinfo end if isfirst then out_unit_table.valinfo = { outinfo } -- in case output value of first least significant unit is needed end sign = outinfo.sign tfrac = outinfo.fraction_table if outinfo.is_scientific then strforce = outinfo.show decimals = '' elseif tfrac then decimals = '' else decimals = (outinfo.show):match('[' .. numdot .. '](.*)') or '' -- outinfo.show is in local language end fmt = '%.' .. ulen(decimals) .. 'f' -- to reproduce precision if decimals == '' then if tfrac then outvalue = floor(outinfo.raw_absvalue) -- integer part only; fraction added later else outvalue = floor(outinfo.raw_absvalue + 0.5) -- keep all integer digits of least significant unit end else outvalue = outinfo.absvalue end end if scale then outvalue, thisvalue = divide(outvalue, scale) else thisvalue = outvalue end local id			if want_name then if varname then local clean if strforce or tfrac then clean = '.1' -- dummy value to force name for floating point else clean = format(fmt, thisvalue) end id = variable_name(clean, out_current) else id = out_current[(thisvalue == 1) and 'name1' or 'name2'] end else id = out_current['symbol'] end if want_link then local link = out_current.link if link then id = make_link(link, id, out_current) end end local strval local inout = (i == #combos or outvalue == 0) and 'out' or '' -- trick so the last value processed (first displayed) has uppercase, if requested if strforce and outvalue == 0 then sign = '' -- any sign is in strforce strval = strforce -- show small values in scientific notation; will only use least significant unit elseif tfrac then local wholestr = (thisvalue > 0) and tostring(thisvalue) or nil strval = format_fraction(parms, inout, false, wholestr, tfrac.numstr, tfrac.denstr, do_spell) else strval = (thisvalue == 0) and from_en('0') or with_separator(parms, format(fmt, thisvalue)) if do_spell then strval = spell_number(parms, inout, strval) or strval end end table.insert(results, strval .. sep1 .. id) if outvalue == 0 then break end fmt = '%.0f' -- only least significant unit can have a non-integral value end local reversed, count = {}, #results for i = 1, count do			reversed[i] = results[count + 1 - i]		end return true, sign .. table.concat(reversed, sep2) end local valinfo = in_unit_table.valinfo local success, result = make_result(valinfo[1], true) if not success then return false, result end local range = parms.range if range then for i = 1, range.n do			local success, result2 = make_result(valinfo[i+1]) if not success then return false, result2 end result = range_text(range[i], want_name, parms, result, result2) end end return true, result .. mid end

local function process(parms, in_unit_table, out_unit_table) -- Return true, s where s = final wikitext result, -- or return false, t where t is an error message table. linked_pages = {} local success, bad_output, out_first local bad_input_mcode = in_unit_table.bad_mcode -- false if input unit is valid local invalue1 = in_unit_table.valinfo[1].value local out_unit = parms.out_unit if out_unit == nil or out_unit == '' then if bad_input_mcode then bad_output = '' else success, out_unit = get_default(invalue1, in_unit_table) parms.out_unit = out_unit if not success then bad_output = out_unit end end end if not bad_output and not out_unit_table then success, out_unit_table = lookup(out_unit, parms.opt_sp_us, 'any_combination') if success then local mismatch = check_mismatch(in_unit_table, out_unit_table) if mismatch then bad_output = mismatch end else bad_output = out_unit_table end end local flipped = parms.opt_flip and not bad_input_mcode local parts = {} for part = 1, 2 do -- The LHS (parts[1]) is normally the input, but is the output if flipped. -- Process LHS first so it will be linked, if wanted. -- Linking to the same item is suppressed in the RHS to avoid overlinking. if (part == 1 and not flipped) or (part == 2 and flipped) then parts[part] = process_input(parms, in_unit_table) elseif bad_output then if bad_output ~= '' then parts[part] = message(bad_output) end else local outputs = {} local combos -- nil (for 'ft' or 'ftin'), or table of unit tables (for 'm ft') if not out_unit_table.multiple then -- nil/false ('ft' or 'm ft'), or table of factors ('ftin') combos = out_unit_table.combination end local frac = parms.frac -- nil or denominator of fraction for output values if frac then -- Apply fraction to the unit (if only one), or to non-SI units (if a combination), -- except that if a precision is also specified, the fraction only applies to				-- the hand unit; that allows the following result: -- 156 cm → 156 centimetres (61.4 in; 15.1½ hands) -- However, the following is handled elsewhere as a special case: -- 156 cm → 156 centimetres (15.1½ hands; 61½ in) if combos then local precision = parms.precision for _, unit in ipairs(combos) do						if unit.builtin == 'hand' or (not precision and not unit.prefixes) then unit.frac = frac end end else out_unit_table.frac = frac end end local imax = combos and #combos or 1 -- 1 (single unit) or number of unit tables for i = 1, imax do				local success, item local out_current = combos and combos[i] or out_unit_table out_current.inout = 'out' if i == 1 then out_first = out_current if imax > 1 and out_current.builtin == 'hand' then out_current.out_next = combos[2] -- built-in hand can influence next unit in a combination end end if out_current.multiple then success, item = make_output_multiple(parms, in_unit_table, out_current) else success, item = make_output_single(parms, in_unit_table, out_current) end if not success then return false, item end table.insert(outputs, item) end local sep = parms.table_joins and parms.table_joins[2] or '; ' parts[part] = parms.opt_input_unit_only and '' or table.concat(outputs, sep) end end if parms.opt_sortable_in or parms.opt_sortable_out then local value if parms.opt_sortable_in then value = invalue1 else local info = out_first and out_first.valinfo if info then info = info[1] value = info.raw_absvalue if value and info.sign == MINUS then value = -value end end end parts[1] = ntsh((value or 0), parms.opt_sortable_debug) .. parts[1] end local wikitext if bad_input_mcode then wikitext = parts[1] .. message(bad_input_mcode) elseif parms.table_joins then wikitext = parms.table_joins[1] .. parts[1] .. parms.table_joins[2] .. parts[2] else wikitext = parts[1] .. parms.joins[1] .. parts[2] .. parms.joins[2] end if parms.warnings and not bad_input_mcode then wikitext = wikitext .. parms.warnings end return true, wikitext, out_unit_table end

local function main_convert(frame) -- Do convert, and if needed, do it again with higher default precision. set_config(frame) local result, out_unit_table local success, parms, in_unit_table = get_parms(frame:getParent) if success then for i = 1, 2 do -- use counter so cannot get stuck repeating convert success, result, out_unit_table = process(parms, in_unit_table, out_unit_table) if success and parms.do_convert_again then parms.do_convert_again = false else break end end else result = parms end if success then return result end return message(result) end

return { convert = main_convert }