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From: Stefan Monnier <monnier@iro.umontreal.ca>
To: help-gnu-emacs@gnu.org
Subject: Re: Lexical binding and macros.
Date: Wed, 15 Dec 2010 10:40:08 -0500	[thread overview]
Message-ID: <jwvipyv11zk.fsf-monnier+gnu.emacs.help@gnu.org> (raw)
In-Reply-To: 96134923-1314-4675-bd77-004945a7159e@y3g2000vbm.googlegroups.com

> Do they still leak memory?  From http://c2.com/cgi/wiki?EmacsLisp :

> "Note that variables bound with lexical-let are never released, even
> if they are never used. Try

>  (loop for i from 1 to 100000 collect (lexical-let ((x i)) '()))

> and watch it eat memory. So making infinity (ZeroOneInfinity) lexical
> variables is out of the question except for very small values of
> infinity."

Additionally to what Pascal already explained, I'll add that,
lexical-let, like `loop' are relatively heavy macros, so you definitely
don't want to run them interpreted (where the macro is re-expanded each
time).  If you byte-compile the code above, the memory use will
be identical to what you get with

  (loop for i from 1 to 100000 collect (let ((x i)) '()))

  
        Stefan


  parent reply	other threads:[~2010-12-15 15:40 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <mailman.40.1292017369.4804.help-gnu-emacs@gnu.org>
2010-12-12  4:10 ` Lexical binding and macros Barry Margolin
2010-12-12 17:14   ` LanX
2010-12-12 17:23     ` Pascal J. Bourguignon
2010-12-15  4:24       ` Stefan Monnier
2010-12-15  9:15         ` Elena
2010-12-15 12:38           ` Pascal J. Bourguignon
2010-12-15 15:40           ` Stefan Monnier [this message]
2010-12-15 16:16             ` David Kastrup
2010-12-15 17:37               ` Pascal J. Bourguignon
2010-12-15 17:54               ` Elena
2010-12-16 21:59               ` Stefan Monnier
2010-12-10 21:42 Alin Soare

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