From: "Brian F. Feldman" <green@...>
Date: 2001-01-20T17:38:55+09:00
Subject: [ruby-talk:9592] Re: rescue / ensure

Bernd Lorbach <berndlor@t-online.de> wrote:
> Hi,
> 
> I don't understand what the ensure-clause is for.
> If you have
> 
> 	f = File.open ...
> 	begin
> 		...
> 	rescue
> 		puts "Error: #{$!}"
> 	ensure
> 		f.close
> 	end
> 
> you just could do
> 
> 	f = File.open ...
> 	begin
> 		...
> 	rescue
> 		puts "Error: #{$!}"
> 	end
> 	f.close
> 
> I think the latter one looks more symmetric and does just the same
> as the former version, as the rescue clause ensures, that the
> program is continued after the begin/end block.
> Am I missing something?

Yes, ensure "always" does its job:

	f = File.open ...
	begin
		...
		return something
	rescue
		puts "Error: #{$!}"
	ensure
		f.close
	end

The return happens but it passes control to the ensure first, in this 
example.  Fun, huh?

-- 
 Brian Fundakowski Feldman           \  FreeBSD: The Power to Serve!  /
 green@FreeBSD.org                    `------------------------------'