content: sub error1()
      print a ' error
  end sub
  
  sub error2()
      print ("2*a=" + (2 * a)) ' error
  end sub
  
  sub error3()
      Rnd(a) ' error
  end sub
  
  sub error4()
      a = 1
      Rnd(function ()
          return a 'error
      end function)
  end sub
  