Path: csiph.com!usenet.pasdenom.info!news.albasani.net!newsfeed.freenet.ag!news2.euro.net!newsfeed.xs4all.nl!newsfeed5.news.xs4all.nl!xs4all!post.news.xs4all.nl!not-for-mail
Return-Path: <python@mrabarnett.plus.com>
X-Original-To: python-list@python.org
Delivered-To: python-list@mail.python.org
X-Spam-Status: OK 0.001
X-Spam-Evidence: '*H*': 1.00; '*S*': 0.00; '(at': 0.03; 'exception': 0.03; 'explicitly': 0.04; 'mrab': 0.05; 'false,': 0.07; 'closed,': 0.09; 'closed.': 0.09; 'record.': 0.09; 'skipped.': 0.09; 'skipping': 0.09; 'subject:command': 0.09; 'anyway': 0.11; 'deleted,': 0.16; 'from:addr:mrabarnett.plus.com': 0.16; 'from:addr:python': 0.16; 'from:name:mrab': 0.16; 'hidden,': 0.16; 'iterating': 0.16; 'merely': 0.16; 'message- id:@mrabarnett.plus.com': 0.16; 'record?': 0.16; 'wrote:': 0.17; 'pointer': 0.17; '>>>': 0.18; 'raise': 0.24; 'least': 0.25; 'header:In-Reply-To:1': 0.25; 'header:User-Agent:1': 0.26; 'setting': 0.26; 'possibly': 0.27; "doesn't": 0.28; 'fine': 0.28; 'record': 0.28; '(possibly': 0.29; 'received:192.168.1.3': 0.29; 'no,': 0.29; 'that.': 0.30; 'file': 0.32; "aren't": 0.33; 'controls': 0.33; 'to:addr:python-list': 0.33; 'version': 0.34; 'options:': 0.35; 'table': 0.35; 'there': 0.35; 'next': 0.35; 'does': 0.37; 'option': 0.37; 'ones': 0.37; 'subject:: ': 0.38; 'mean': 0.38; 'to:addr:python.org': 0.39; 'received:192': 0.39; 'received:192.168': 0.40; 'think': 0.40; 'header:Reply-To:1': 0.68; 'records': 0.68; 'reply-to:no real name:2**0': 0.72; 'disappear': 0.84; 'furman': 0.84; 'reply-to:addr:python.org': 0.84; 'seventh': 0.84; 'ethan': 0.91; 'subject:records': 0.91
X-CM-Score: 0.00
X-CNFS-Analysis: v=2.0 cv=aJVyWMBm c=1 sm=1 a=0nF1XD0wxitMEM03M9B4ZQ==:17 a=YsUzL_8ObRgA:10 a=NAy-WIAmZUIA:10 a=ihvODaAuJD4A:10 a=OUOv7kDek9cA:10 a=8nJEP1OIZ-IA:10 a=EBOSESyhAAAA:8 a=8AHkEIZyAAAA:8 a=zv8U2pdCvixzQtzTd-EA:9 a=wPNLvfGTeEIA:10 a=0nF1XD0wxitMEM03M9B4ZQ==:117
X-AUTH: mrabarnett:2500
Date: Wed, 18 Jul 2012 03:57:33 +0100
From: MRAB <python@mrabarnett.plus.com>
User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:13.0) Gecko/20120614 Thunderbird/13.0.1
MIME-Version: 1.0
To: python-list@python.org
Subject: Re: Foxpro goto command and deleted records
References: <5005EDC0.6050608@stoneleaf.us> <5005FCE0.5020204@mrabarnett.plus.com> <50061D2E.8080204@stoneleaf.us>
In-Reply-To: <50061D2E.8080204@stoneleaf.us>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
X-BeenThere: python-list@python.org
X-Mailman-Version: 2.1.12
Precedence: list
Reply-To: python-list@python.org
List-Id: General discussion list for the Python programming language <python-list.python.org>
List-Unsubscribe: <http://mail.python.org/mailman/options/python-list>, <mailto:python-list-request@python.org?subject=unsubscribe>
List-Archive: <http://mail.python.org/pipermail/python-list>
List-Post: <mailto:python-list@python.org>
List-Help: <mailto:python-list-request@python.org?subject=help>
List-Subscribe: <http://mail.python.org/mailman/listinfo/python-list>, <mailto:python-list-request@python.org?subject=subscribe>
Newsgroups: comp.lang.python
Message-ID: <mailman.2261.1342580250.4697.python-list@python.org>
Lines: 43
NNTP-Posting-Host: 2001:888:2000:d::a6
X-Trace: 1342580250 news.xs4all.nl 6909 [2001:888:2000:d::a6]:57989
X-Complaints-To: abuse@xs4all.nl
Xref: csiph.com comp.lang.python:25554

On 18/07/2012 03:19, Ethan Furman wrote:
> MRAB wrote:
>> On 17/07/2012 23:57, Ethan Furman wrote:
>>> In Foxpro if you do a
>>>
>>> GOTO 7
>>>
>>> with deleted off and record 7 is deleted, the record pointer doesn't
>>> move (at least in version 6).
>>>
>>> I don't like that.
>>>
>>> I see four other options:
>>>
>>> 0) don't move the pointer (listed for completeness)
>>> 1) go to that record anyway
>>> 2) go to the next undeleted record
>>> 3) go to the seventh undeleted record (possibly the least practical)
>>> 4) raise an exception
>>>
>>> Any opinions?
>>>
>> What happens when you 'delete' a record? Does it disappear immediately,
>> or is it merely marked for deletion?
>
> Marked for deletion.
>
>> If it is marked for deletion, can it be unmarked? Will a marked record
>> be removed when the file is closed, or does the file need to be
>> explicitly purged/compacted?
>
> Yes, it can be unmarked.  No, the table must be explicitly packed.
>
>> If it is merely marked, then I think the best option is 1, or possibly
>> 4 if the file is compacted when closed.
>
> There is a use_deleted setting that controls whether deleted records are
> accessed or skipped.  Skipping is fine when looping, not so fine when
> going directly to a particular record.
>
If use_deleted is false, does that mean that deleted records are
hidden, or just that when iterating through the records the deleted
ones aren't yielded?