content: sub error1()
      a = 1
      print A ' error
      print "a="; A ' error
      some(A) ' error
      some(1 + A) ' error
  end sub
  
  sub error2()
      a = 1
      A = 2 ' error
  end sub
  
  sub error3(A)
      a = 2 ' error
  end sub
  
  sub ok1()
      A = 1
      print A
      print "A="; A
      some(A)
      some(1 + A)
  end sub
  
  sub some(p)
      print p
  end sub
  