From z Mon Dec 04 18:36:08 2000 Received: from maguro.epr.com ([198.3.162.27]) by exchange.epr.com with SMTP (Microsoft Exchange Internet Mail Service Version 5.5.2650.21) id WNKA3CAL; Mon, 4 Dec 2000 09:34:05 -0800 Received: from magrathea.epr.com (firewall-user@magrathea.epr.com [198.3.160.1]) by maguro.epr.com (8.9.3/8.9.3) with ESMTP id JAA11648 for ; Mon, 4 Dec 2000 09:38:00 -0800 (PST) Received: (from uucp@localhost) by magrathea.epr.com (8.9.3/8.7.3) id JAA21949 for ; Mon, 4 Dec 2000 09:37:59 -0800 (PST) Received: from nodnsquery(199.222.69.4) by magrathea.epr.com via smap (V5.5) id xma021535; Mon, 4 Dec 00 09:37:06 -0800 Received: from clairv.com (IDENT:root@pc246.edi.nunet.net [199.249.165.246]) by mail.acm.org (8.9.3/8.9.3) with ESMTP id MAA24844 for ; Mon, 4 Dec 2000 12:37:01 -0500 Received: from magrathea.epr.com (firewall-user@magrathea.epr.com [198.3.163.3]) by clairv.com (8.9.3/8.9.3) with ESMTP id LAA31738 for ; Mon, 4 Dec 2000 11:37:01 -0600 Received: (from uucp@localhost) by magrathea.epr.com (8.9.3/8.7.3) id JAA21500 for ; Mon, 4 Dec 2000 09:36:59 -0800 (PST) Received: from unknown(198.3.162.27) by magrathea.epr.com via smap (V5.5) id xma021136; Mon, 4 Dec 00 09:36:08 -0800 Received: from eponym.epr.com (eponym.epr.com [10.1.1.123]) by maguro.epr.com (8.9.3/8.9.3) with ESMTP id JAA11480; Mon, 4 Dec 2000 09:36:08 -0800 (PST) Received: (from sweeks@localhost) by eponym.epr.com (8.9.3/8.9.3) id JAA20999; Mon, 4 Dec 2000 09:36:08 -0800 From: "Stephen Weeks" MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <14891.54792.694163.309467@eponym.epr.com> Date: Mon, 4 Dec 2000 09:36:08 -0800 (PST) To: MLton@sourcelight.com Cc: jhr@research.bell-labs.com Reply-to: MLton@sourcelight.com Subject: Re: CWS paper In-Reply-To: <200012041728.LAA08907@nimrod.clairv.com> References: <200012041728.LAA08907@nimrod.clairv.com> X-Mailer: VM 6.71 under 20.4 "Emerald" XEmacs Lucid X-Spam-Checker-Version: SpamAssassin 2.60 (1.212-2003-09-23-exp) on eponym.sweeks.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=3.0 tests=AWL autolearn=no version=2.60 > Stephen knows this stuff better than I, but I know that we talked a lot to > Richard about his experiences with full CPS conversion and I know that the > notion of using CPS to express the intra-procedural flow was from him. At > the time I was arguing for the advantages of CPS (over direct style) and I > remember showing an example from Shiver's thesis where top-level procedures > were transformed into continuations (because they always were called with the > same continuation). I think that Stephen put contification into MLton in > response to that. (Although it might have waited until he saw that this was > going to be required for nested loops, as in matrix multiplication.) That all sounds right. I remember the most annoying problem that we had with the direct style IL was that we were allocating tuples for code like the following: val (x, y) = if ... then (a, b) else (c, d) This was absolutely killing us in some benchmarks. We could have gone to some variant of a direct style IL that allowed a "flat" tuple to be returned in the branches of the if, but it was so much easier to go to CPS with multi-argument continuations and do: fun L (x, y) = ... if ... then L (a, b) else L (c, d)