From: Yukihiro Matsumoto <matz@...>
Date: 2009-03-06T17:44:05+09:00
Subject: [ruby-core:22699] Re: [Bug #1248] e.exception(e) returns self

Hi,

In message "Re: [ruby-core:22698] Re: [Bug #1248] e.exception(e) returns self"
    on Fri, 6 Mar 2009 16:52:47 +0900, Tomas Matousek <Tomas.Matousek@microsoft.com> writes:

|Well the reason is that arg is supposed to be a message, right? A message can be an arbitrary object. So if I pass e as a message, why it doesn't become a value of the message property?

The arg is supposed to be an exception, or exception class, or a
message, which means arg is a message only when arg is a string.  The
whole purpose of exception method is to duck-type raise semantics,
that is

  raise ExceptionClass   # specifying exception class

to make a new exception, and

  raise anException      # specifying exception object

to re-raise the exception.

							matz.