From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <oleg@okmij.org>
X-Original-To: caml-list@sympa.inria.fr
Delivered-To: caml-list@sympa.inria.fr
Received: from mail2-relais-roc.national.inria.fr (mail2-relais-roc.national.inria.fr [192.134.164.83])
	by sympa.inria.fr (Postfix) with ESMTPS id BBEA47EE49
	for <caml-list@sympa.inria.fr>; Thu, 19 Sep 2013 08:18:40 +0200 (CEST)
Received-SPF: None (mail2-smtp-roc.national.inria.fr: no sender
  authenticity information available from domain of
  oleg@okmij.org) identity=pra; client-ip=66.39.3.115;
  receiver=mail2-smtp-roc.national.inria.fr;
  envelope-from="oleg@okmij.org"; x-sender="oleg@okmij.org";
  x-conformance=sidf_compatible
Received-SPF: Pass (mail2-smtp-roc.national.inria.fr: domain of
  oleg@okmij.org designates 66.39.3.115 as permitted sender)
  identity=mailfrom; client-ip=66.39.3.115;
  receiver=mail2-smtp-roc.national.inria.fr;
  envelope-from="oleg@okmij.org"; x-sender="oleg@okmij.org";
  x-conformance=sidf_compatible; x-record-type="v=spf1"
Received-SPF: None (mail2-smtp-roc.national.inria.fr: no sender
  authenticity information available from domain of
  postmaster@www1.g3.pair.com) identity=helo;
  client-ip=66.39.3.115;
  receiver=mail2-smtp-roc.national.inria.fr;
  envelope-from="oleg@okmij.org";
  x-sender="postmaster@www1.g3.pair.com";
  x-conformance=sidf_compatible
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: AokHALCWOlJCJwNzXWdsb2JhbABaxT6BNwMYBw4GPoIseRs0VRQUiAi6IY9nBxaECAOXegGVGDw
X-IPAS-Result: AokHALCWOlJCJwNzXWdsb2JhbABaxT6BNwMYBw4GPoIseRs0VRQUiAi6IY9nBxaECAOXegGVGDw
X-IronPort-AV: E=Sophos;i="4.90,934,1371074400"; 
   d="scan'208";a="33458234"
Received: from www1.g3.pair.com ([66.39.3.115])
  by mail2-smtp-roc.national.inria.fr with SMTP; 19 Sep 2013 08:18:38 +0200
Received: (qmail 17830 invoked by uid 9370); 19 Sep 2013 06:18:38 -0000
Date: 19 Sep 2013 06:18:38 -0000
Message-ID: <20130919061838.17829.qmail@www1.g3.pair.com>
From: oleg@okmij.org
To: yotambarnoy@gmail.com
CC: caml-list@inria.fr
In-reply-to:
	<CAN6ygOniyQEo421humUzA4eAeMjjJvfXLKePeJounYzANhZ-Kw@mail.gmail.com>
Subject: Re: [Caml-list] Expanding the Float Array tag


I am curious about the focus on generalizing double_tag or
double_array_tag when there is already a seemingly good candidate for
tagging values that should not be scanned. I mean the
string_tag. Please search the OCaml code for string_tag and
String_tag. You see it is mentioned in generic routines like
generic comparison compare.c -- which uses memcpy anyway, thus
treating the string just like a sequence of bytes. Other generic
functions like hash are similar. The only other non-trivial use of
string_tag is in printexc and the likes. Those cases are indeed
problematic. Other than them, string_tag can denote arbitrary opaque
byte array and noone will notice. Incidentally, if by string we mean
UTF-8 or UTF-16 string, it is essentially a sequence of bytes anyway.