Ruby 的异常类层次

Ruby的异常类层次：

Exception 
    * fatal  
    * NoMemoryError  
    * ScriptError  
          o LoadError  
          o NotImplementedError  
          o SyntaxError  
    * SignalException  
          o Interrupt  
    * StandardError  
          o ArgumentError  
          o IOError  
                + EOFError  
          o IndexError  
          o LocalJumpError  
          o NameError  
                + NoMethodError  
          o RangeError  
                + FloatDomainError  
          o RegexpError  
          o RuntimeError  
          o SecurityError  
          o SystemCallError  
          o ThreadError  
          o TypeError  
          o ZeroDivisionError  
    * SystemExit  
    * SystemStackError