func Init:java
  fvar(old)
  old = block.select((isset(BLK_FUNC) and isndef(Extern)) ? BLK_FUNC : BLK_HEAD)
  println(issec("php") ? '' : 'var ', prev_data, ' = ', Store, ';')
  block.select(old)
end

func doCalcDelta(_data):java
  fvar(dt)
  dt = Data
  if(linked(Result))
    println(delta, ' = ', dt, ' - ', prev_data, ';')
    event(onCalcDelta, delta)
  else
    event(onCalcDelta, dt && ' - ' && prev_data)
  end
  println(prev_data, ' = ', dt, ';')  
end

func Result():java
  fvar(dt,res)
  dt = Data
  if(linked(doCalcDelta))
    res = delta
  else
    res = dt && ' - ' && prev_data
  end
  println(prev_data, ' = ', dt, ';')
  return(res)
end