From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (from majordomo@localhost) by pauillac.inria.fr (8.7.6/8.7.3) id RAA00542; Sun, 2 Jun 2002 17:16:02 +0200 (MET DST) X-Authentication-Warning: pauillac.inria.fr: majordomo set sender to owner-caml-list@pauillac.inria.fr using -f Received: from concorde.inria.fr (concorde.inria.fr [192.93.2.39]) by pauillac.inria.fr (8.7.6/8.7.3) with ESMTP id RAA00708 for ; Sun, 2 Jun 2002 17:16:01 +0200 (MET DST) Received: from sunny.pacific.net.au (sunny.pacific.net.au [203.25.148.40]) by concorde.inria.fr (8.11.1/8.11.1) with ESMTP id g52FFv510424; Sun, 2 Jun 2002 17:15:58 +0200 (MET DST) Received: from wisma.pacific.net.au (wisma.pacific.net.au [210.23.129.72]) by sunny.pacific.net.au with ESMTP id g52FFoZr000844; Mon, 3 Jun 2002 01:15:50 +1000 (EST) Received: from ozemail.com.au (ppp172.dyn145.pacific.net.au [210.23.145.172]) by wisma.pacific.net.au with ESMTP id BAA23627; Mon, 3 Jun 2002 01:15:47 +1000 (EST) Message-ID: <3CFA36A2.1020408@ozemail.com.au> Date: Mon, 03 Jun 2002 01:15:46 +1000 From: John Max Skaller User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.2.1) Gecko/20010901 X-Accept-Language: en-us MIME-Version: 1.0 To: Pierre Weis CC: warplayer@free.fr, garrigue@kurims.kyoto-u.ac.jp, caml-list@inria.fr Subject: Re: [Caml-list] about Obj.magic References: <200206011742.TAA16993@pauillac.inria.fr> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-caml-list@pauillac.inria.fr Precedence: bulk Pierre Weis wrote: >>An 'almost legal' use of Obj.magic is to populate an array with dummy >>values. >>For example: >> >> class Deep .. >> let a = Array.make 100 (Obj.magic 0 :> Deep) in >> let len_a = ref 0 in >> >>This is roughly as safe as an unsafe array access, >>only now the array length is a variable. >> >>-- >>John Max Skaller, mailto:skaller@ozemail.com.au >>snail:10/1 Toxteth Rd, Glebe, NSW 2037, Australia. >>voice:61-2-9660-0850 >> > >I'm afraid that this use is not ``almost legal'' and, on the contrary, >it is strongly discouraged by good programming practice! > And I'm sorry too, because it is the only way to achieve the desired effect: Ocaml could do well with a variable length array in the standard library, IMHO. -- John Max Skaller, mailto:skaller@ozemail.com.au snail:10/1 Toxteth Rd, Glebe, NSW 2037, Australia. voice:61-2-9660-0850 ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners