From: Sean O'Halpin <sean.ohalpin@...>
Date: 2005-12-09T08:08:27+09:00
Subject: Re: rescue anything raised?

On 12/8/05, Jeffrey Moss <jeff@opendbms.com> wrote:
> rescue Exception
>
> All exceptions descend from class Exception.
>
That's not quite true. Compare:

  begin
    eval "foo *"
  rescue Exception => e
    p e
  end

-- OUTPUT --
#<SyntaxError: (eval):1: compile error
(eval):1: syntax error
foo *
     ^>

versus

  begin
    eval "foo *"
  rescue SyntaxError
    puts "syntax error"
  rescue Exception => e
    p e
  end

-- OUTPUT --
syntax error

There is a forest of exceptions not a tree. To capture an exception
generally, you have to specify which family you want to intercept. The
top level families of exception are: NoMemoryError, ScriptError,
SignalException, StandardError, SystemExit and SystemStackError.

You can find the Exception class hierarchy in Pickaxe 2, p. 109.

Regards,

Sean