-- This module is intended to replace the functionality of Template:Formatnum and related templates.  local p = {}  function p.main(frame)     local args = frame:getParent().args     local prec    = args.prec or     local sep     = args.sep or      local number  = args[1] or args.number or     local lang    = args[2] or args.lang or      -- validate the language parameter within MediaWiki's caller frame     if lang == "arabic-indic" then -- only for back-compatibility ("arabic-indic" is not a SupportedLanguage)         lang = "fa" -- better support than "ks"     elseif lang ==  or not mw.language.isSupportedLanguage(lang) then         -- Note that 'SupportedLanguages' are not necessarily 'BuiltinValidCodes', and so they are not necessarily         -- 'KnownLanguages' (with a language name defined at least in the default localisation of the local wiki).         -- But they all are ValidLanguageCodes (suitable as Wiki subpages or identifiers: no slash, colon, HTML tags, or entities)         -- In addition, they do not contain any capital letter in order to be unique in page titles (restriction inexistant in BCP47),         -- but they may violate the standard format of BCP47 language tags for specific needs in MediaWiki.         -- Empty/unspecified and unsupported languages are treated here in Commons using the user's language,         -- instead of the local 'ContentLanguage' of the Wiki.         lang = frame:callParserFunction( "int", "lang" ) -- get user's chosen language     end     return p.formatNum(number, lang, prec, sep ~= ) end  local digit = { -- substitution of decimal digits for languages not supported by mw.language:formatNum() in core Lua libraries for MediaWiki     ["ml-old"] = { '൦', '൧', '൨', '൩', '൪', '൫', '൬', '൭', '൮', '൯' },     ["mn"]     = { '᠐', '᠑', '᠒', '᠓', '᠔', '᠕', '᠖', '᠗', '᠘', '᠙'},     ["ta"]     = { '௦', '௧', '௨', '௩', '௪', '௫', '௬', '௭', '௮', '௯'},     ["te"]     = { '౦', '౧', '౨', '౩', '౪', '౫', '౬', '౭', '౮', '౯'},     ["th"]     = { '๐', '๑', '๒', '๓', '๔', '๕', '๖', '๗', '๘', '๙'} }  function p.formatNum(number, lang, prec, compact)      -- Do not alter the specified value when it is not a valid number, return it as is     local value = tonumber(number)     if value == nil then         return number     end     -- Basic ASCII-only formatting (without paddings)     number = tostring(value)      -- Check the presence of an exponent (incorrectly managed in mw.language:FormatNum() and even forgotten due to an internal bug, e.g. in Hindi)     local exponent     local pos = string.find(number, '[Ee]')     if pos ~= nil then         exponent = string.sub(number, pos + 1, string.len(number))         number = string.sub(number, 1, pos - 1)     else         exponent =     end      -- Check the minimum precision requested     prec = tonumber(prec) -- nil if not specified as a true number     if prec ~= nil then         prec = math.floor(prec)         if prec < 0 then             prec = nil -- discard an incorrect precision (not a positive integer)         elseif prec > 14 then             prec = 14 -- maximum precision supported by tostring(number)         end     end      -- Preprocess the minimum precision in the ASCII string     local dot     if (prec or 0) > 0 then         pos = string.find(number, '.', 1, true) -- plain search, no regexp         if pos ~= nil then             prec = pos + prec - string.len(number) -- effective number of trailing decimals to add or remove             dot =  -- already present         else             dot = '.' -- must be added         end     else         dot =  -- don't add dot         prec = 0 -- don't alter the precision     end      if lang ~= nil and mw.language.isKnownLanguageTag(lang) == true then         -- Convert number to localized digits, decimal separator, and group separators         local language = mw.getLanguage(lang)         if compact then             number = language:formatNum(tonumber(number), { noCommafy = 'y' }) -- caveat: can load localized resources for up to 20 languages         else             number = language:formatNum(tonumber(number)) -- caveat: can load localized resources for up to 20 languages         end         -- Postprocessing the precision         if prec > 0 then             local zero = language:formatNum(0)             number = number .. dot .. mw.ustring.rep(zero, prec)         elseif prec < 0 then             -- TODO: rounding of last decimal; here only truncate decimals in excess             number = mw.ustring.sub(number, 1, mw.ustring.len(number) + prec)         end          -- Append the localized base-10 exponent without grouping separators (there's no reliable way to detect a localized leading symbol 'E')         if exponent ~=  then             number = number .. 'E' .. language:formatNum(tonumber(exponent),{noCommafy=true})         end     else -- not localized, ASCII only         -- Postprocessing the precision         if prec > 0 then             number = number .. dot .. mw.string.rep('0', prec)         elseif prec < 0 then             -- TODO: rounding of last decimal; here only truncate decimals in excess             number = mw.string.sub(number, 1, mw.string.len(number) + prec)         end          -- Append the base-10 exponent         if exponent ~= '' then             number = number .. 'E' .. exponent         end     end      -- Special cases for substitution of ASCII digits (missing support in Lua core libraries for some languages)     if digit[lang] then         for i, v in ipairs(digit[lang]) do             number = mw.ustring.gsub(number, tostring(i - 1), v)         end     end      return number end  return p