-- This module implements {{Roman}}. local p = {} -- This function implements the {{overline}} template. local function overline( s ) return mw.ustring.format( '%s', s ) end -- Gets the Roman numerals for a given numeral table. Returns both the string of -- numerals and the value of the number after it is finished being processed. local function getLetters( num, t ) local ret = {} for _, v in ipairs( t ) do local val, letter = unpack( v ) while num >= val do num = num - val table.insert( ret, letter ) end end return table.concat( ret ), num end -- The main control flow of the module. local function _main( args ) -- Get input and exit displaying nothing if the input is bad. local num = tonumber( args[ 1 ] ) if not num or num < 1 or num == math.huge then return end num = math.floor( num ) -- Return a message for numbers too big to be expressed in Roman numerals. if num >= 5000000 then return args[ 2 ] or 'N/A' end local ret = '' -- Find the Roman numerals for the large part of numbers 5000 and bigger. -- The if statement is not strictly necessary, but makes the algorithm -- more efficient for smaller numbers. if num >= 5000 then local bigRomans = { { 1000000, 'M' }, { 900000, 'CM' }, { 500000, 'D' }, { 400000, 'CD' }, { 100000, 'C' }, { 90000, 'XC' }, { 50000, 'L' }, { 40000, 'XL' }, { 10000, 'X' }, { 5000, 'V' } } local bigLetters bigLetters, num = getLetters( num, bigRomans ) ret = overline( bigLetters ) end -- Find the Roman numerals for numbers 4999 or less. local smallRomans = { {1000, "M"}, {900, "CM"}, {500, "D"}, {400, "CD"}, {100, "C"}, {90, "XC"}, {50, "L"}, {40, "XL"}, {10, "X"}, {9, "IX"}, {5, "V"}, {4, "IV"}, {1, "I"} } local smallLetters = getLetters( num, smallRomans ) ret = ret .. smallLetters return ret end function p.main( frame ) -- If called via #invoke, use the args passed into the invoking -- template, or the args passed to #invoke if any exist. Otherwise -- assume args are being passed directly in from the debug console -- or from another Lua module. local origArgs if frame == mw.getCurrentFrame() then origArgs = frame:getParent().args for k, v in pairs( frame.args ) do origArgs = frame.args break end else origArgs = frame end -- Trim whitespace and remove blank arguments. local args = {} for k, v in pairs( origArgs ) do if type( v ) == 'string' then v = mw.text.trim( v ) end if v ~= '' then args[k] = v end end return _main( args ) end return p 