From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Original-To: caml-list@yquem.inria.fr Delivered-To: caml-list@yquem.inria.fr Received: from concorde.inria.fr (concorde.inria.fr [192.93.2.39]) by yquem.inria.fr (Postfix) with ESMTP id A20E4BB81 for ; Fri, 11 Nov 2005 22:22:33 +0100 (CET) Received: from pauillac.inria.fr (pauillac.inria.fr [128.93.11.35]) by concorde.inria.fr (8.13.0/8.13.0) with ESMTP id jABLMWsW023720 for ; Fri, 11 Nov 2005 22:22:33 +0100 Received: from nez-perce.inria.fr (nez-perce.inria.fr [192.93.2.78]) by pauillac.inria.fr (8.7.6/8.7.3) with ESMTP id WAA00481 for ; Fri, 11 Nov 2005 22:22:32 +0100 (MET) Received: from out4.smtp.messagingengine.com (out4.smtp.messagingengine.com [66.111.4.28]) by nez-perce.inria.fr (8.13.0/8.13.0) with ESMTP id jABLMV8g013590 for ; Fri, 11 Nov 2005 22:22:32 +0100 Received: from frontend1.internal (mysql-sessions.internal [10.202.2.149]) by frontend1.messagingengine.com (Postfix) with ESMTP id 4AE9FCDD4E7; Fri, 11 Nov 2005 16:22:30 -0500 (EST) Received: from frontend2.messagingengine.com ([10.202.2.151]) by frontend1.internal (MEProxy); Fri, 11 Nov 2005 16:22:30 -0500 X-Sasl-enc: KHcE+hBhuapGL472xIbBL+6ywXqKq9Y/Jpi467213PZb 1131744149 Received: from munge (burnham.ljcrf.edu [192.231.106.2]) by frontend2.messagingengine.com (Postfix) with ESMTP id 0D18957295B; Fri, 11 Nov 2005 16:22:27 -0500 (EST) Date: Fri, 11 Nov 2005 13:22:19 -0800 (PST) From: Martin Jambon X-X-Sender: martin@munge To: Thomas Fischbacher Cc: caml-list@inria.fr Subject: Re: [Caml-list] What on earth is this? In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Miltered: at concorde with ID 43750B99.000 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)! X-Miltered: at nez-perce with ID 43750B97.001 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)! X-Spam: no; 0.00; caml-list:01 beginner's:01 memoized:01 rec:01 hashtbl:01 memoized:01 right-hand:01 rec':01 hashtbl:01 rec:01 2005,:98 ...:98 ...:98 wrote:01 expression:01 X-Spam-Checker-Version: SpamAssassin 3.0.3 (2005-04-27) on yquem.inria.fr X-Spam-Level: X-Spam-Status: No, score=0.1 required=5.0 tests=FORGED_RCVD_HELO autolearn=disabled version=3.0.3 On Fri, 11 Nov 2005, Thomas Fischbacher wrote: > Maybe I just need a good night of sleep, maybe I overlooked something > really dumb and rather should have asked on the beginner's list. Anyway, > I find the behaviour demonstrated below quite confusing. Why don't the > definitions ###_v1 and ###_v2 work? Any idea, anyone? > let memoized ht f arg = ... ... > let rec mem_fibonacci_v1 = > let mem = Hashtbl.create 10 in > memoized mem > (fun n -> if n < 2 then 1 else mem_fibonacci_v1 (n-1) + > mem_fibonacci_v1 (n-2)) > ;; > (* Error: "This kind of expression is not allowed as right-hand side of `let rec'" *) > > let mem_fibonacci_v2 = > let mem = Hashtbl.create 10 in > let rec mf = > memoized mem > (fun n -> if n < 2 then 1 else (mf (n-1)) + (mf (n-2))) > in mf > ;; Almost there. This should work: let mem_fibonacci_v2 = let mem = Hashtbl.create 10 in let rec mf arg = memoized mem (fun n -> if n < 2 then 1 else (mf (n-1)) + (mf (n-2))) arg in mf Martin -- Martin Jambon, PhD - http://martin.jambon.free.fr Open Bioinformatics at http://wikiomics.org