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From: Ted Dennison<dennison@telepath.com>
Subject: Re: List container strawman
Date: Fri, 02 Nov 2001 15:06:37 GMT
Date: 2001-11-02T15:06:37+00:00	[thread overview]
Message-ID: <1EyE7.10050$xS6.13527@www.newsranger.com> (raw)
In-Reply-To: 9rti6v$hcu$1@news.huji.ac.il

In article <9rti6v$hcu$1@news.huji.ac.il>, Ehud Lamm says...
>1. In my scheme "Element" is a generic parameter of the top package
>(Containers), and not of the specific implementations.
>(Remember, my attemp for having interface inheritance)

I didn't do that because that is precisely what Booch does that makes it so
complicated to use. If one does that, then proper use of the package would
require 3 cascading generic package instantiations. If that is OK, then in my
opinion we should just bag this whole thing and use Booch.

>2. Why is List private? Shouldn't it be limited private, so we avoid
>possible erros caused by aliasing?

First off, I'd like to note for anyone who may have missed it, that any Element
passed in to be put on a list or taken off of one will be *copied*. Pointers to
elements will not be used.

If List were limited private, then we'd have to get rid of all those "&"
routines. My thinking was that Lisp-like functional list processing would be
desirable. You could indeed have aliasing problems, but only if your Element
type uses pointers. Having "&" avaliable also makes list operations somewhat
consistent with arrays, which also have "&".

However, any use of those "&" routines will involve creating a copy of every
element (much like using "&" with arrays does). That would probably be too
expensive in most cases, so perhaps it really isn't all that valuable. I'm
curious how others feel about this.

>(If the majority wants private, at least the spec should mention the
>possbile problems)

I can agree with this. At the least there should be some sort of warning in
there about using pointers in Element with those routines.

>3. "Construct" is indeed a long name. We can, as part of the library, decide
>on some standard name for this like - or +

As the comment said, I seriously considered that. However, it is not (yet) a
common idiom to use those for constructors. So I'm not sure if it would help or
hurt readability. Again, I'm curious what people think about this.

>4. I've seen many implemenations that paremtrize Insert and Remove with a
>direction parameter, instead of having seperate routines (_Back/_Front). I
>am not sure I know which approach I prefer...

>5. Front() and Back() raise execption on Empty List?

Assuming you are talking about the iterator routines "First" and "Last", that's
a good point. I seem to have totally neglected that case, and thus left serious
problems in there. For instance, the comment that says "For an empty list, First
= Last." is clearly wrong. That would indicate a list with one element, not an
empty one. I'll have to redo the iterators somehow...


>6. I like having a "No_More_Elements()" operation as part of the Iterator
>interface. It saves time compared to Size (for containers that don't keep
>count of size), and I don't like programming with exceptions ("exceptions
>for control flow").

That seems sensible. And I agree about using exceptions, which is why it is only
one example of 3. That stuff is all wrong anyway though...

>7. Sort should be in a child unit.

Why do you feel that way? What does putting it off in a separate unit gain you?

>
>Finally, a more general question:
>Is this a DeQueue or a Doubly-linked list? Should these be two different
>abstractions? (IMO: Yes, they should).

What specificly would the difference be?

Clearly it would have to be doubly-linked to support all those push and pop
operations, and both Next and Previous as iterators. You could implement those
on a singly-linked list, but it wouldn't be very efficient.

---
T.E.D.    homepage   - http://www.telepath.com/dennison/Ted/TED.html

No trees were killed in the sending of this message. 
However a large number of electrons were terribly inconvenienced.



  parent reply	other threads:[~2001-11-02 15:06 UTC|newest]

Thread overview: 166+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-11-02  3:56 List container strawman Ted Dennison
2001-11-02  4:20 ` James Rogers
2001-11-02 14:23   ` Ted Dennison
2001-11-02 14:38     ` Preben Randhol
2001-11-02 15:15     ` Larry Kilgallen
2001-11-02  4:35 ` Eric Merritt
2001-11-02 15:46   ` Ted Dennison
2001-11-02  7:28 ` Ehud Lamm
2001-11-02 14:57   ` Marin David Condic
2001-11-02 15:57     ` Francisco Javier Loma Daza
2001-11-02 16:28       ` Marin David Condic
2001-11-02 17:08         ` Ted Dennison
2001-11-02 15:06   ` Ted Dennison [this message]
2001-11-02 15:32     ` Marin David Condic
2001-11-02 16:33       ` Ted Dennison
2001-11-02 16:43         ` Marin David Condic
2001-11-02 22:51           ` Jeffrey Carter
2001-11-03  0:24             ` Matthew Heaney
2001-11-03  2:21               ` Jeffrey Carter
2001-11-03 22:51                 ` Rosen Trick [List container strawman] Nick Roberts
2001-11-04 13:07                   ` Robert Dewar
2001-11-04 17:17                     ` Side-Effects in Functions [Rosen Trick] Nick Roberts
2001-11-05  2:46                       ` Robert Dewar
2001-11-05  7:26                         ` pete
2001-11-05 10:29                           ` Dmitry A. Kazakov
2001-11-05 11:19                             ` pete
2001-11-05 14:59                               ` Dmitry A. Kazakov
2001-11-05 15:21                                 ` Preben Randhol
2001-11-05 16:04                                   ` Ted Dennison
2001-11-05 16:33                                   ` Dmitry A. Kazakov
2001-11-05 17:42                                     ` Warren W. Gay VE3WWG
2001-11-05 18:11                                       ` Preben Randhol
2001-11-06  8:38                                       ` Dmitry A. Kazakov
2001-11-06  9:31                                         ` tgingold
2001-11-06  0:10                             ` Nick Roberts
2001-11-06  9:30                               ` Dmitry A. Kazakov
2001-11-06 16:18                                 ` Lazy Evaluation [Side-Effects in Functions] Nick Roberts
2001-11-07  3:42                                   ` Robert Dewar
2001-11-07  4:42                                     ` Darren New
2001-11-07 11:54                                       ` Robert Dewar
2001-11-07 13:32                                         ` Florian Weimer
2001-11-07 13:24                                           ` Jean-Marc Bourguet
2001-11-09 18:06                                         ` Ted Dennison
2001-11-09 18:27                                           ` M. A. Alves
2001-11-11 20:13                                           ` Georg Bauhaus
2001-12-06 17:47                                             ` Harri J Haataja
2001-11-07  9:28                                   ` Dmitry A. Kazakov
2001-11-06 20:08                               ` Side-Effects in Functions [Rosen Trick] Florian Weimer
2001-11-06 22:48                                 ` Nick Roberts
2001-11-07 10:46                                   ` Florian Weimer
2001-11-05 13:56                           ` Robert Dewar
2001-11-05 16:08                             ` Ted Dennison
2001-11-05 17:44                               ` Warren W. Gay VE3WWG
2001-11-05 15:56                         ` Ted Dennison
2001-11-05 18:46                         ` Nick Roberts
2001-11-08 11:51                           ` Georg Bauhaus
2001-11-16  0:31                 ` List container strawman Vincent Marciante
2001-11-05 15:10             ` Marin David Condic
2001-11-05 18:31               ` Ted Dennison
2001-11-05 19:09                 ` Marin David Condic
2001-11-05 21:23                   ` Ted Dennison
2001-11-07 19:27                   ` Stephen Leake
2001-11-02 18:11         ` Mark Johnson
2001-11-02 18:46           ` Marin David Condic
2001-11-02 19:21           ` Larry Kilgallen
2001-11-03 22:30         ` Nick Roberts
2001-11-02 16:26   ` Ted Dennison
2001-11-02 16:36     ` Marin David Condic
2001-11-02 19:31       ` Ted Dennison
2001-11-02 17:49     ` Jeffrey Carter
2001-11-08 10:34     ` Ehud Lamm
2001-11-08 18:53       ` Better Finalisation [List container strawman] Nick Roberts
2001-11-09 13:36         ` Robert Dewar
2001-11-09 15:04           ` Florian Weimer
2001-11-10  0:36           ` Nick Roberts
2001-11-09 15:16         ` Ted Dennison
2001-11-09 17:30         ` Better control of assignment Jeffrey Carter
2001-11-10  0:32           ` Nick Roberts
2001-11-10 22:27             ` Jeffrey Carter
2001-11-13  6:36               ` Craig Carey
2001-11-13  6:39               ` Craig Carey
2001-11-13  8:53               ` Craig Carey
2001-11-14  9:42                 ` Craig Carey
2001-11-09 14:49       ` List container strawman Ted Dennison
2001-11-09 16:12         ` Ehud Lamm
2001-11-09 17:12         ` Marin David Condic
2001-11-09 18:11           ` Ted Dennison
2001-11-09 18:42           ` Matthew Heaney
2001-11-10 17:54             ` Simon Wright
2001-11-02 14:49 ` Marin David Condic
2001-11-02 15:15   ` Ted Dennison
2001-11-02 15:37     ` Marin David Condic
2001-11-02 16:49       ` Ted Dennison
2001-11-02 17:09         ` Marin David Condic
2001-11-04  0:10           ` Nick Roberts
2001-11-03 23:41         ` Nick Roberts
2001-11-02 17:02 ` David Botton
2001-11-02 17:55   ` David Botton
2001-11-03 19:22 ` Nick Roberts
     [not found] ` <3BE29AF4.80804@telepath.com>
2001-11-02 13:14   ` Ted Dennison
2001-11-02 13:31     ` Larry Kilgallen
2001-11-02 15:09       ` Ted Dennison
2001-11-02 15:13         ` Preben Randhol
2001-11-02 20:48       ` David Starner
2001-11-02 22:49         ` Larry Kilgallen
2001-11-02 17:44     ` Jeffrey Carter
2001-11-02 20:07       ` Ted Dennison
2001-11-02 23:19         ` Jeffrey Carter
2001-11-03  6:56           ` Ted Dennison
2001-11-03 19:22             ` Jeffrey Carter
2001-11-04 18:58               ` Darren New
2001-11-04 19:40                 ` Larry Kilgallen
2001-11-04 20:49                   ` Darren New
2001-11-07 19:07                   ` ramatthews
2001-11-08  0:04                     ` Darren New
2001-11-08  4:50                     ` Jeffrey Carter
2001-11-08 23:26                       ` ramatthews
2001-11-09 18:00                     ` Ted Dennison
2001-11-09 18:13                       ` Jean-Marc Bourguet
2001-11-09 18:55                         ` Ted Dennison
2001-11-10  1:48                           ` Nick Roberts
2001-11-10 17:04                             ` Ted Dennison
2001-11-10 20:59                               ` Nick Roberts
2001-11-10 23:17                                 ` Larry Hazel
2001-11-11  3:27                                   ` Nick Roberts
2001-11-12 18:39                                     ` Darren New
2001-11-13  0:35                                       ` Nick Roberts
2001-11-10 19:36                             ` Ehud Lamm
2001-11-10 20:15                               ` Nick Roberts
2001-11-09 19:27                       ` Larry Kilgallen
2001-11-09 20:03                       ` Stephen Leake
2001-11-09 21:05                         ` Ted Dennison
2001-11-09 22:42                         ` Larry Kilgallen
2001-11-10  4:52                           ` Nick Roberts
2001-11-10 20:24                       ` ramatthews
2001-11-05 19:28                 ` Ted Dennison
2001-11-05 19:42                   ` Jean-Marc Bourguet
2001-11-05 20:40                     ` Ted Dennison
2001-11-05 20:24                   ` Darren New
2001-11-05 20:45                     ` Ted Dennison
2001-11-05 17:21         ` List container strawman; Construct alternatives Stephen Leake
2001-11-03  7:42       ` List container strawman Simon Wright
2001-11-05 14:00   ` Stephen Leake
2001-11-08 11:17     ` Simon Wright
2001-11-13 16:29       ` Stephen Leake
2001-11-13 22:43         ` Jeffrey Carter
2001-11-13 22:48         ` Jeffrey Carter
2001-11-14  3:46           ` Nick Roberts
2001-11-15 10:23             ` Ehud Lamm
2001-11-14 14:50           ` Marin David Condic
2001-11-14 16:53             ` Jeffrey Carter
2001-11-14 17:59               ` Marin David Condic
2001-11-15  3:33                 ` Nick Roberts
2001-11-15 15:10                   ` Marin David Condic
2001-11-16  1:29                     ` Nick Roberts
2001-11-16 16:03                       ` Marin David Condic
2001-11-16 20:19                         ` Nick Roberts
2001-11-15 18:08                   ` Matthew Heaney
2001-11-08 14:57 ` M. A. Alves
2001-11-09  2:00   ` Jeffrey Carter
2001-11-09 18:31   ` Ted Dennison
2001-11-10 19:56     ` Ehud Lamm
  -- strict thread matches above, loose matches on Subject: below --
2001-11-02 19:54 Mike Brenner
2001-11-02 21:04 ` Ted Dennison
2001-11-03  8:09   ` Simon Wright
2001-11-03 12:46     ` Simon Wright
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