Module:Roman

-- This module implements {{Roman}}.local p = {}-- This function implements the {{overline}} template.local function overline( s )    return mw.ustring.format( '<span style="text-decoration:overline;">%s</span>', 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 ), numend-- 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 retendfunction 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 )endreturn p