function OnCalculate(index)
 
  if index == 1 then
    
    _ds = getDataSourceInfo()
 --....
    
  end
  
  return 0
  
end 

function OnCalculate(index)
  
  local _ds = nil
  
  if index == 1 then
    
    _ds = getDataSourceInfo()
 --....
    
  end
  
  return 0
  
end 

local _ds;
function OnCalculate(index)
  if index == 1 then   
    _ds = getDataSourceInfo()
  --....
  end
 
  return 0
  
end

name="light"

Settings = {}
Settings.Name = name;
Settings.line = {};
Settings.step = 0
Settings.secId = ''
Settings.size = 0

function OnCalculate(index)
  
  local _ds = nil
  
  if index == 1 then
    
    _ds = getDataSourceInfo()
    Settings.secId = _ds.sec_code
    
    Settings.size = getNumCandles(Settings.secId)    
    Settings.step = Settings.step + 1
    
  end

  PrintDbgStr('OnCalculate. Settings.secId '..Settings.secId..' Index '..index..' . Step : '..Settings.step..' size : '..Settings.size)
  
  return 0
  
end
--------
function Init()
  
  local t = Settings.line;
  
  t[#t+1] = { Name = 'zero', Color = RGB(0,128,255), Type = 0, Width = 1}
  
  return #t
  
end