From: Andrea Taverna <a.tavs@hotmail.it>
Subject: A few Ada questions
Date: Thu, 23 Jul 2009 15:58:21 -0700 (PDT)
Date: 2009-07-23T15:58:21-07:00 [thread overview]
Message-ID: <ead315e7-7ce4-4445-a2cc-04ca6f82dcd1@o15g2000yqm.googlegroups.com> (raw)
In-Reply-To: b846beee-774f-48d2-a0c3-00ccebc29b64@h18g2000yqj.googlegroups.com
I've got a few questions about Ada, generated from discussion
<h3sln0$rhm$2@news.eternal-september.org>.
I apologize for my annoying newbieness :D
On 18 Lug, 17:50, Ludovic Brenta <ludo...@ludovic-brenta.org> wrote:
> Andrea Taverna wrote:
>
> [...]
>
> > So I have considered these alternatives: FreePascal, Eiffel, Ada and
> > Modula-3
[....]
> > As for memory management (requirement 4), I heard there are different
> > takes on the matter:
> > (a) Ada uses dynamic stack allocation a lot, and in a transparent way,
> > reducing the need of manual management (MM)
> > (b) Ada libraries adopt idioms that further simplifies MM issues
> > (c) Conservative garbage collectors such as Bohem's can be used with
> > Ada, and they are supposed to work "better" with Ada than with unsafe
> > languages such as C and C++
>
> I have to add:
> (d) controlled types allow you to control allocation and
> deallocation without a garbage collector.
>
> > So can MM be said to be easier in Ada than in C? I hope Ada-ers will
> > mercifully shed some light on the issue.
>
> Yes, MM is definitely easier in Ada than in C; my experience with
> Java's garbage collector is that (a) you never learn to manage memory,
> and (b) is is very easy to run out of memory and get the infamous
> OutOfMemoryError. That has never happened to me in Ada, simply
> because Ada forces me to think about this problem.
>
> Another reason why Ada is easier than C is because you use pointers
> only for what they were designed: dynamic allocation and
> deallocation. As a consequence, each time you introduce a pointer you
> naturally think about memory management. Contrast this to C where
> simple parameter passing often requires pointers, and with Eiffel or
> Java where everything is a pointer whether you like it or not.
>
So I took a deeper look at Ada, and if I'm not mistaken, the MM
support in Ada boils down to
1) dynamic stack allocation
2) malloc/free with Unchecked_Allocation
3) Controlled types that allow you implement constructors and
destructors
4) Storage pools.
Apart from (1) and (4), (2) and (3) seem to provide the same
functionality of corresponding C++ features, with the notable
exception that (3) requires tagging the type (*).
As for (4), I couldn't find a practical example of storage pools usage
on the net, I'd really like to see one.
The storage pool I have in mind is the one used in ObjC/Cocoa, i.e. a
storage pool with ref-counted objects. Users can send retain/release
messages to increment/decrement the pool-allocated object's reference
count. In which way does this differ from storage pools in Ada?
I know that they have several benefits compared with pool-less
storage, you can define a homogeneously typed/sized pool improving the
memory management for associated types, and you can implement MM more
easily, but, still, the problems I have with MM (at least in C) are :
- application-specific code is intertwined with MM and vice versa. It
complicates interfaces and hinders reusability.
- objects have a graph-like relationship on which MM depends that
could not be easy to foresee.
- due to the graph relationship, refactoring MM code, which can ease
MM itself, gets harder.
How is Ada supposed to help with this?
(*) besides, I infer that the visibility checks required for
controlled types exposed at inner levels can be disabled at run-time,
right?
Finally, I'd have a question about the standard container library. I'm
probably a bit confused since I've recently been hopping from a
language to the other, but I saw that Containers do not define
interfaces and Cursors types are not tagged.
As such I'm not sure whether I can extend new containers from standard
ones, including defining new cursors, while having polymorphic
behaviour.
For example, can I define a linked-list implemented with an array by
deriving a standard container?
thanks,
Andrea
next prev parent reply other threads:[~2009-07-23 22:58 UTC|newest]
Thread overview: 267+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-18 14:19 Alternatives to C: ObjectPascal, Eiffel, Ada or Modula-3? Andrea Taverna
2009-07-18 14:42 ` Richard Harter
2009-07-18 14:53 ` Francois PIETTE
2009-07-18 15:23 ` Ludovic Brenta
2009-07-18 18:27 ` Andrea Taverna
2009-07-18 18:46 ` Pascal Obry
2009-08-04 20:09 ` Hendrik Boom
2009-08-04 21:35 ` Jon Harrop
2009-07-18 18:57 ` Andrea Taverna
2009-07-18 15:18 ` Pascal J. Bourguignon
2009-07-19 13:50 ` Andrea Taverna
2009-07-19 14:06 ` Pascal J. Bourguignon
2009-07-20 10:13 ` Nicholas Paul Collin Gloucester
2009-08-04 20:12 ` Hendrik Boom
2009-07-21 12:03 ` Jon Harrop
2009-07-21 13:25 ` Mark T.B. Carroll
2009-07-18 15:50 ` Ludovic Brenta
2009-07-18 16:31 ` Hibou57 (Yannick Duchêne)
2009-07-18 19:48 ` Georg Bauhaus
2009-07-20 10:34 ` Nicholas Paul Collin Gloucester
2009-07-23 22:58 ` Andrea Taverna [this message]
2009-07-24 0:28 ` A few Ada questions Ludovic Brenta
2009-07-24 9:07 ` AdaMagica
2009-07-28 9:48 ` Making a nonlimited type controlled by means of a controlled component Ludovic Brenta
2009-08-14 22:21 ` Randy Brukardt
2009-08-14 22:51 ` Adam Beneschan
2009-07-24 7:00 ` A few Ada questions Dmitry A. Kazakov
2009-07-24 15:26 ` Colin Paul Gloster
2009-07-24 15:01 ` Dmitry A. Kazakov
2009-07-18 16:27 ` Alternatives to C: ObjectPascal, Eiffel, Ada or Modula-3? BGB / cr88192
2009-07-18 17:41 ` Ben Bacarisse
2009-07-20 10:39 ` Nicholas Paul Collin Gloucester
2009-07-20 16:17 ` Ben Bacarisse
2009-07-21 12:10 ` Jon Harrop
2009-07-21 14:40 ` Colin Paul Gloster
2009-07-22 0:25 ` Andrew Reilly
2009-07-19 1:04 ` Andrew Reilly
2009-07-19 13:14 ` mockturtle
2009-07-19 13:35 ` Andrea Taverna
2009-07-19 15:28 ` Pascal J. Bourguignon
2009-07-19 17:30 ` Hibou57 (Yannick Duchêne)
2009-07-19 18:02 ` Georg Bauhaus
2009-07-19 19:09 ` Hibou57 (Yannick Duchêne)
2009-07-19 19:14 ` Pascal J. Bourguignon
2009-07-19 19:51 ` Georg Bauhaus
2009-07-19 19:52 ` tm
2009-07-20 9:57 ` Jean-Pierre Rosen
2009-07-20 13:42 ` Hibou57 (Yannick Duchêne)
2009-07-20 14:37 ` tm
2009-07-20 15:14 ` Jean-Pierre Rosen
2009-07-24 7:26 ` tm
2009-07-24 8:10 ` Dmitry A. Kazakov
2009-07-25 17:39 ` Frank J. Lhota
2009-07-25 18:12 ` Dmitry A. Kazakov
2009-07-24 21:15 ` Wolfgang Ehrhardt
2009-07-24 22:29 ` bartc
2009-07-26 10:55 ` tm
2009-07-26 12:14 ` bartc
2009-07-26 13:21 ` Pascal J. Bourguignon
2009-07-26 15:43 ` bartc
2009-07-20 15:46 ` Georg Bauhaus
2009-07-20 16:08 ` Ben Bacarisse
2009-07-20 19:48 ` Tetrahedral Quartz
2009-07-26 2:26 ` wwilson
2009-07-20 12:15 ` Nicholas Paul Collin Gloucester
2009-07-20 12:59 ` Mark T.B. Carroll
2009-07-20 13:18 ` Nicholas Paul Collin Gloucester
2009-07-20 13:21 ` Mark T.B. Carroll
2009-07-20 14:49 ` Nicholas Paul Collin Gloucester
2009-07-20 18:33 ` Cesar Rabak
2009-07-20 18:49 ` Hibou57 (Yannick Duchêne)
2009-07-20 19:35 ` Cesar Rabak
2009-07-20 21:54 ` Georg Bauhaus
2009-07-21 7:39 ` Dmitry A. Kazakov
2009-07-21 14:30 ` Cesar Rabak
2009-07-21 15:17 ` Martin
2009-07-20 19:23 ` Georg Bauhaus
2009-07-20 19:55 ` Cesar Rabak
2009-07-21 12:49 ` Colin Paul Gloster
2009-07-20 19:44 ` Nicholas Paul Collin Gloucester
2009-07-20 20:14 ` Cesar Rabak
2009-07-20 22:22 ` Ludovic Brenta
2009-07-21 1:33 ` Cesar Rabak
2009-07-21 7:54 ` Ludovic Brenta
2009-07-21 7:59 ` Dmitry A. Kazakov
2009-07-21 13:08 ` Colin Paul Gloster
2009-07-21 12:43 ` Dmitry A. Kazakov
2009-07-21 14:48 ` Cesar Rabak
2009-07-21 14:45 ` Cesar Rabak
2009-07-21 15:46 ` Dmitry A. Kazakov
2009-07-21 17:34 ` Colin Paul Gloster
2009-07-21 8:56 ` Jean-Pierre Rosen
2009-07-21 9:31 ` Georg Bauhaus
2009-07-21 15:02 ` Cesar Rabak
2009-07-21 16:42 ` Georg Bauhaus
2009-07-21 18:00 ` Cesar Rabak
2009-07-22 14:10 ` Colin Paul Gloster
2009-07-22 14:54 ` Cesar Rabak
2010-03-24 2:46 ` Robert Love
2010-03-25 15:51 ` Colin Paul Gloster
2009-07-21 17:37 ` Colin Paul Gloster
2009-07-21 14:08 ` Hibou57 (Yannick Duchêne)
2009-07-21 13:38 ` Colin Paul Gloster
2009-07-21 15:25 ` Cesar Rabak
2009-07-21 17:48 ` Colin Paul Gloster
2009-07-23 18:47 ` Jon Harrop
2009-07-23 19:20 ` Colin Paul Gloster
2009-07-23 21:51 ` Jon Harrop
2009-07-24 1:08 ` Cesar Rabak
2009-07-24 7:04 ` Dmitry A. Kazakov
2009-07-22 19:29 ` sjw
2009-07-22 20:05 ` Dmitry A. Kazakov
2009-07-23 12:01 ` Colin Paul Gloster
2009-07-24 1:19 ` Cesar Rabak
2009-07-24 8:50 ` Georg Bauhaus
2009-07-24 15:56 ` Colin Paul Gloster
2009-07-24 16:52 ` Colin Paul Gloster
2009-07-24 18:36 ` Cesar Rabak
2009-07-24 21:46 ` Robert A Duff
2009-07-25 14:32 ` jimmaureenrogers
2009-07-25 17:31 ` Cesar Rabak
2009-07-21 12:25 ` Jon Harrop
2009-07-21 11:41 ` Martin
2009-07-21 14:09 ` Jon Harrop
2009-07-21 13:41 ` Martin
2009-07-21 13:45 ` Martin
2009-07-21 13:58 ` Dmitry A. Kazakov
2009-07-21 16:06 ` Jon Harrop
2009-07-21 15:54 ` Georg Bauhaus
2009-07-22 9:37 ` Jon Harrop
2009-07-22 9:19 ` Georg Bauhaus
2009-07-22 7:53 ` Martin
2009-07-22 9:18 ` Jon Harrop
2009-07-21 23:17 ` Robert A Duff
2009-07-21 14:12 ` Andrea Taverna
2009-07-21 14:14 ` Hibou57 (Yannick Duchêne)
2009-07-21 14:38 ` Hibou57 (Yannick Duchêne)
2009-07-21 15:29 ` Mark T.B. Carroll
2009-07-21 16:10 ` Jon Harrop
2009-07-22 8:16 ` Martin
2009-07-22 18:59 ` Jon Harrop
2009-07-24 8:15 ` tm
2009-07-24 9:31 ` Jon Harrop
2009-07-24 9:42 ` Georg Bauhaus
2009-07-24 13:03 ` Jon Harrop
2009-07-24 10:15 ` tm
2009-07-24 13:11 ` Jon Harrop
2009-07-24 13:01 ` tm
2009-07-24 14:42 ` Jon Harrop
2009-07-25 1:15 ` wwilson
2009-07-25 6:05 ` robertwessel2
2009-07-25 9:24 ` Dmitry A. Kazakov
2009-07-26 2:10 ` wwilson
2009-07-26 3:27 ` Andrew Reilly
2009-07-26 10:08 ` bartc
2009-07-27 11:28 ` Colin Paul Gloster
2009-07-28 5:01 ` wwilson
2009-07-28 10:13 ` Colin Paul Gloster
2009-07-28 12:29 ` Dave Seaman
2009-07-28 12:42 ` Peter Hermann
2009-07-28 18:35 ` wwilson
2009-07-21 13:09 ` parnell
2009-07-28 20:57 ` fft1976
2009-07-28 21:59 ` Georg Bauhaus
2009-07-28 22:01 ` Ludovic Brenta
2009-07-30 3:04 ` fft1976
2009-07-30 6:47 ` Martin
2009-07-28 23:14 ` Jon Harrop
2009-08-01 19:46 ` frankenstein
2009-08-01 21:56 ` Paul Rubin
2009-08-01 23:28 ` Jon Harrop
2009-08-02 10:07 ` frankenstein
2009-08-02 18:55 ` Jon Harrop
2009-08-02 9:48 ` frankenstein
2009-07-29 0:40 ` Oxide Scrubber
2009-07-29 2:52 ` fft1976
2009-07-29 4:46 ` Oxide Scrubber
2009-07-29 7:50 ` Elena
2009-07-29 15:06 ` Andrea Taverna
2009-07-29 8:11 ` Ray Blaak
2009-07-29 9:57 ` learn2code
2009-07-29 11:38 ` Oxide Scrubber
2009-07-29 14:03 ` learn2code
2009-07-29 14:35 ` Pascal J. Bourguignon
2009-07-29 17:02 ` Oxide Scrubber
2009-08-03 11:19 ` oxhiderubber
2009-07-29 21:10 ` Jon Harrop
[not found] ` <kctwcdo5pewe.1ut3dcff8axm0$.dlg@40tude.net>
2009-07-29 21:18 ` Jon Harrop
2009-07-29 16:36 ` Colin Paul Gloster
2009-07-29 17:22 ` Ray Blaak
2009-07-29 18:44 ` Martin
2009-07-29 20:58 ` Jon Harrop
2009-07-29 15:19 ` Andrea Taverna
2009-07-29 19:25 ` Jon Harrop
2009-07-30 2:11 ` tmoran
2009-07-30 2:34 ` fft1976
2009-07-30 2:48 ` Paul Rubin
2009-07-30 3:40 ` fft1976
2009-07-30 3:53 ` Paul Rubin
2009-07-30 6:51 ` Georg Bauhaus
2009-07-30 7:52 ` fft1976
2009-07-30 8:34 ` Ludovic Brenta
2009-07-30 16:10 ` Georg Bauhaus
2009-07-30 17:09 ` fft1976
2009-07-30 17:20 ` Pascal Obry
2009-07-30 17:28 ` fft1976
2009-07-30 17:47 ` Isaac Gouy
2009-07-31 10:48 ` Georg Bauhaus
2009-07-30 17:23 ` Ludovic Brenta
2009-07-30 17:59 ` Isaac Gouy
2009-07-30 19:38 ` fft1976
2009-07-30 21:44 ` Isaac Gouy
2009-07-30 22:14 ` Paul Rubin
2009-07-31 10:27 ` Georg Bauhaus
2009-07-31 11:13 ` Georg Bauhaus
2009-07-31 11:29 ` Georg Bauhaus
2009-07-31 16:38 ` Isaac Gouy
2009-07-30 16:25 ` Isaac Gouy
2009-07-30 12:28 ` Colin Paul Gloster
2009-07-30 11:49 ` Martin
2010-03-23 12:31 ` balson
2010-03-23 12:56 ` balson
2010-03-23 13:24 ` Georg Bauhaus
2010-03-23 15:05 ` Maciej Sobczak
2010-03-23 17:52 ` Georg Bauhaus
2010-03-24 6:33 ` Martin Krischik
2010-03-24 8:31 ` Maciej Sobczak
2010-03-23 16:50 ` Warren
2010-03-23 20:29 ` Patrick Scheible
2010-03-24 15:07 ` Warren
2010-03-24 21:11 ` Patrick Scheible
2010-03-24 21:27 ` Pascal J. Bourguignon
2010-03-24 22:14 ` Adam Beneschan
2010-03-24 23:15 ` Patrick Scheible
2010-03-24 23:24 ` Adam Beneschan
2010-03-24 23:28 ` Patricia Shanahan
2010-03-25 1:52 ` John B. Matthews
2010-03-25 16:42 ` Andrew Haley
2010-03-26 23:54 ` Pascal J. Bourguignon
2010-03-24 21:36 ` Adam Beneschan
2010-03-26 7:58 ` Martin Krischik
2010-04-12 11:03 ` Ole-Hjalmar Kristensen
2010-03-24 6:28 ` Martin Krischik
2010-03-24 15:10 ` Warren
2010-03-25 2:19 ` Mike Sieweke
2010-03-25 13:48 ` Robert A Duff
2010-03-25 15:42 ` Colin Paul Gloster
2010-03-26 15:54 ` blmblm
2010-03-26 19:18 ` Warren
2010-03-27 0:03 ` Pascal J. Bourguignon
2010-03-23 17:12 ` J-P. Rosen
2010-03-23 17:41 ` Jim Balson
2010-03-23 17:54 ` Pascal Obry
2010-03-23 18:34 ` jpwoodruff
2010-03-23 20:34 ` Patrick Scheible
2010-03-23 20:33 ` Patrick Scheible
2010-03-23 20:39 ` Pascal Obry
2010-03-24 6:24 ` Martin Krischik
2010-03-23 19:33 ` Adam Beneschan
2010-03-23 22:02 ` Mensanator
2010-03-31 6:55 ` David Thompson
2010-03-31 8:08 ` Martin Krischik
2010-03-24 15:15 ` Warren
2010-03-25 15:46 ` Colin Paul Gloster
2010-03-27 0:53 ` Andrea Taverna
2010-03-27 6:19 ` Gautier write-only
2010-03-23 17:31 ` Patrick Scheible
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