Hexadecimal to Decimal and HexColors to RGB Converter

function hexToDec(num)
     if type(num)=="number" then
         error("String expected, got number.", 1)
     end
     local K=string.len(num)
     local N=K-1
     local sum=0
     local Z,R,G,B,r
     local chars={}
     for n in num:gmatch("[%w+]") do
         table.insert(chars, n)
     end
     for key,v in ipairs(chars) do
         if v=="A" then
             chars[key]=tonumber(10)
         elseif v=="B" then
             chars[key]=tonumber(11)
         elseif v=="C" then
             chars[key]=tonumber(12)
         elseif v=="D" then
             chars[key]=tonumber(13)
         elseif v=="E" then
             chars[key]=tonumber(14)
         elseif v=="F" then
             chars[key]=tonumber(15)
         end
     end
     if K==6 then
         R=(chars[1]*16)+(chars[2])
         G=(chars[3]*16)+(chars[4])
         B=(chars[5]*16)+(chars[6])
         r="R: "..R.."\nG: "..G.."\nB: "..B
         return r
     else
         for i=1,K do
             Z=(chars[i]*16^N)
             sum=sum+Z
             N=N-1
             if N==1 then
                 break
             end
         end
     end
     return sum
end

print(hexToDec("FFFFFF"))