From: Jim Weirich <jweirich@...>
Date: 2003-05-20T13:57:49+09:00
Subject: Re: An Object Going Out Of Scope

On Mon, 2003-05-19 at 11:55, MikkelFJ wrote:

> The Ruby interpreter nows pretty well when the scope exits and it could
> easily call a default method on all auto references. auto could even be
> given a name, but probably not arguments. Never mind the syntax, but an
> example could be:
> 
> { auto(:foo); foo = Foo.new } # calling foo.finalize on scope exit
> or
> { auto(:foo, :cleanup); foo = foo.new } # calling foo.cleanup on scope exit

How about this syntax ...

   auto(foo=MyObject.new, :cleanup) do
     # use foo
   end

The above can be written in standard Ruby.

> Wrt.complex scope rules. The scope should not be for an arbitrary variable.
> Some simple rules could be defined and the auto could work an a variable the
> exists before and after the syntactical scope we are in.
> It could even work on global variables. (This is actually useful for
> critical sections and the like):
> 
> { auto(:$critsec, :exit); @critsec.enter; .... }
> 

Critcal sections are better handled by blocks ...

  lock(mutex) do
    # critical section
  end

-- 
-- Jim Weirich     jweirich@one.net    http://jimweirich.umlcoop.net
---------------------------------------------------------------------
"Beware of bugs in the above code; I have only proved it correct, 
not tried it." -- Donald Knuth (in a memo to Peter van Emde Boas)