p = line[index-Settings.startPeriod] or C(index)
   n = k*C(index)+(1-k)*p 
 

function counter_from(i)
   local x=i
   return function ()
      x=x+1
      return x-1
   end
end

c1 = counter_from(1)
c2 = counter_from(100)
for i=1, 10 do
   print("c1 = " .. c1() .. ", c2 = " .. c2())
end
 

c1 = 1, c2 = 100
c1 = 2, c2 = 101
c1 = 3, c2 = 102
c1 = 4, c2 = 103
c1 = 5, c2 = 104
c1 = 6, c2 = 105
c1 = 7, c2 = 106
c1 = 8, c2 = 107
c1 = 9, c2 = 108
c1 = 10, c2 = 109
 

p = line[index-Settings.startPeriod] or C(index)
   n = k*C(index)+(1-k)*p 

Settings= {
   Name = "averEMA",
   startPeriod   = 3,
   endPeriod   = 6,
   line =
   {
      {
         Name      = "AverEMA",
         Type      = TYPE_LINE,
         Width      = 2
      }
   }
}
   
function Init()
   return 1
end

function average(_start, _end)
   local sum=0
   for i = _start, _end do
      sum=sum+C(i)
   end
   return sum/(_end-_start+1)
end

function cached_EMA(__period, __k)
   local cache={}
   local period = __period
   local k = __k or 2/(period+1)
   return function(ind)
      local n = 0
      local p = 0
      --local period = _p
      local index = ind
      if index == 1 then
         cache = {}
      end
      if index < period then
         cache[index] = average(1,index)
         return nil
      end
      p = cache[index-1] or C(index)
      n = k*C(index)+(1-k)*p
      cache[index] = n
      return n
   end
end

function OnCalculate(index)   
   local s=0
   if index == 1 then
      line   = {}
      for i=Settings.startPeriod, Settings.endPeriod do
         line[i - Settings.startPeriod + 1] = cached_EMA(i)
      end
   end

   s = 0
   for i = 1, #line do
      local res = line[i](index)
      if res == nil then
         return nil
      else
         s = s + res
      end
   end
   
   return s/#line
end

 

 Settings= {
   Name = "averEMA",
   startPeriod   = 3,
   endPeriod   = 6,
   line =
   {
      {
         Name      = "AverEMA",
         Color      = RGB(90, 110, 200),
         Type      = TYPE_LINE,
         Width      = 1
      }
   }
}
   
function Init()
   return 1
end

function OnCalculate(index)   
   local s
   
   if index == 1 then
      EMA   = _EMA()
      
      line   = {}
   end

   s = 0
   for i = Settings.startPeriod, Settings.endPeriod do
      local k
      k = EMA(index, i)

      s = s + k
   end
      
   if index <= Settings.endPeriod then
      
      line[index] = 0   
      
   else         
      line[index] = s / (Settings.startPeriod - (Settings.endPeriod - 1))
   end
   
   message("---- message 1 -----")
   message("EMA3 = "..tostring(EMA(index, 3)))
   --message("---- message 2 -----")
   --message("EMA3 = "..tostring(EMA(index, 3))..", EMA4 = "..tostring(EMA(index, 4)))
   
   return line[index]

end
function _MA()
   local cache={}
   
   return function(iIndex, iPeriod)
      local sum      = 0
      local p         = 0
      local period   = iPeriod      
      local index      = iIndex
      local result   = 0
      local str      = ""
      
      if index == 1 then
         cache = {}
      end
      
      if index < period then
         cache[index] = 0
         return 0
      end
      
      for i = index - period + 1, index do
         sum = sum + C(i)
      end
      
      result = sum / period
      
      cache[index] = result
      
      return result
      
   end
end 

function _EMA()
   local cache={}
   local MA = _MA()
   
   return function(ind, _p, kk)
      local n = 0
      local p = 0
      local period = _p
      local index = ind
      local k = kk or 2/(period + 1)      

      if index == 1 then
         cache = {}
      end
      
      if index <= period then
         cache[index] = 0
         
         return 0
      end
      
      if cache[index - 1] == 0
         or cache[index - 1] == nil then
         
         p = MA(index - 1, period)
      else
         p = cache[index - 1]
      end
      
      n = C(index) * k + (1-k)*p
      
      cache[index] = n
      
      return n
   end
end