From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham
	autolearn_force=no version=3.4.4
X-Google-Thread: 103376,21960280f1d61e84
X-Google-Attributes: gid103376,public
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news2.google.com!news4.google.com!newsfeed2.dallas1.level3.net!news.level3.com!newsfeed-00.mathworks.com!nntp.TheWorld.com!not-for-mail
From: Robert A Duff <bobduff@shell01.TheWorld.com>
Newsgroups: comp.lang.ada
Subject: Re: in defense of GC
Date: Mon, 05 Feb 2007 19:18:04 -0500
Organization: The World Public Access UNIX, Brookline, MA
Message-ID: <wccy7nc5ebn.fsf@shell01.TheWorld.com>
References: <1169531612.200010.153120@38g2000cwa.googlegroups.com>
 <mailman.44.1169724732.18371.comp.lang.ada@ada-france.org>
 <WaBuh.15096$pQ3.10501@newsread4.news.pas.earthlink.net>
 <xwsldwre3j.fsf@hod.lan.m-e-leypold.de>
 <md64ashx3o.fsf@hod.lan.m-e-leypold.de>
 <1mahvxskejxe1$.tx7bjdqyo2oj$.dlg@40tude.net>
 <2tfy9vgph3.fsf@hod.lan.m-e-leypold.de>
 <1g7m33bys8v4p.6p9cpsh3k031$.dlg@40tude.net>
 <s1mz41g7d3.fsf@hod.lan.m-e-leypold.de>
 <14hm72xd3b0bq$.axktv523vay8$.dlg@40tude.net>
 <4zwt33xm4b.fsf@hod.lan.m-e-leypold.de>
 <1j7neot6h1udi$.14vp2aos6z9l8.dlg@40tude.net>
 <ubqkd8yk3.fsf@STRIPCAPStelus.net>
 <AuednXvMpOTR8l_YnZ2dnUVZ_ruknZ2d@megapath.net>
 <u7iv18hm3.fsf_-_@STRIPCAPStelus.net>
 <1pzx3y7d2pide.y744copm0ejb$.dlg@40tude.net>
 <hwzm7wafut.fsf@hod.lan.m-e-leypold.de>
 <n7pgtyy2vmsh.1ifb1qd3h8y8t$.dlg@40tude.net>
 <g464ajco2i.fsf@hod.lan.m-e-leypold.de>
 <wcc64ahfo61.fsf@shell01.TheWorld.com> <uodo9pgfe.fsf@STRIPCAPStelus.net>
NNTP-Posting-Host: shell01.theworld.com
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
X-Trace: pcls6.std.com 1170721090 30274 192.74.137.71 (6 Feb 2007 00:18:10
 GMT)
X-Complaints-To: abuse@TheWorld.com
NNTP-Posting-Date: Tue, 6 Feb 2007 00:18:10 +0000 (UTC)
User-Agent: Gnus/5.1008 (Gnus v5.10.8) Emacs/21.3 (irix)
Cancel-Lock: sha1:mc9cmmRnmbH6C6aC0Z8vzftgGEc=
Xref: g2news2.google.com comp.lang.ada:8986
Date: 2007-02-05T19:18:04-05:00
List-Id: <comp.lang.ada>

Ray Blaak <rAYblaaK@STRIPCAPStelus.net> writes:

> Robert A Duff <bobduff@shell01.TheWorld.com> writes:
>> But in the latter, case, the return of Stepper is causing the lifetime
>> of an integer VARIABLE (i.e. mutable) to be longer than one might
>> suspect for a local variable of Make_A_Stepper.  That seems like a
>> problem to me.
>
> Yes, the lifetime is longer (as specified by the programmer) but the global
> visibility is not affected -- N still cannot be directly manipulated in a
> global sense.

My complaint is that it's not specified by the programmer on the
declaration of that variable (mutable object).  Some nested procedure
happens to mention N and that procedure gets returned to a more-global
place, dragging N along with it.  (Yes of course I understand that
"N still cannot be directly manipulated in a global sense.")

I've got no problem with passing functions (closures) outward in a
functional (no mutable variables) context.

- Bob