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From: sbelmont700@gmail.com
Subject: Re: Press Release - Ada 2012 Language Standard Approved by ISO
Date: Thu, 27 Dec 2012 06:29:02 -0800 (PST)
Date: 2012-12-27T06:29:02-08:00	[thread overview]
Message-ID: <895c9eb7-03f8-4b0c-96b4-3dbd7a315ccd@googlegroups.com> (raw)
In-Reply-To: <kbg9bp$a72$1@munin.nbi.dk>

On Wednesday, December 26, 2012 8:47:29 PM UTC-5, Randy Brukardt wrote:

>  As I mentioned last week, exceptions are used for two purposes: one
>  is "checks", which should never fail at all.... The other kind is an
> exceptional termination, like End_Error 


While I agree 100% with the first part, I remain extremely skeptical about the second.  I've yet to be convinced of a case where its necessary/preferable/best-structured to propogate an exception out to be handled by the client instead of making the client check it beforehand.  You show me a subprogram that raises End_Error and I'll show you a subprogram that needs a precondition "not At_End".  If you are rasising "File_Not_Found" then you need a precondition of "File_Exists".  The onus is on the interface to provide the necessary information to the client to ensure exceptions do not happen in the first place, and the onus is on the client to make sure they are met *before* the call, not to swoop in afterwards to clean up the mess.  If you can handle it (that is, correct the actual problem and continue as before), you can prevent it.

-sb



  reply	other threads:[~2012-12-27 14:29 UTC|newest]

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-12-18  7:45 Press Release - Ada 2012 Language Standard Approved by ISO Dirk Craeynest
2012-12-18 16:57 ` Robert A Duff
2012-12-18 21:12   ` Bill Findlay
2012-12-18 21:36     ` Jeffrey Carter
2012-12-18 21:57       ` Bill Findlay
2012-12-19  8:33     ` Dmitry A. Kazakov
2012-12-19  9:00       ` Georg Bauhaus
2012-12-19  9:19         ` Dmitry A. Kazakov
2012-12-19  9:21           ` Georg Bauhaus
2012-12-19  9:38             ` Dmitry A. Kazakov
2012-12-19 12:23               ` Georg Bauhaus
2012-12-19 14:34       ` Bill Findlay
2012-12-20  1:52       ` Randy Brukardt
2012-12-21  9:01         ` Dmitry A. Kazakov
2012-12-21 10:13           ` Georg Bauhaus
2012-12-21 10:34             ` Georg Bauhaus
2012-12-21 13:38             ` Dmitry A. Kazakov
2012-12-22  1:40           ` Randy Brukardt
2012-12-22  9:02             ` Dmitry A. Kazakov
2012-12-22 22:38               ` Georg Bauhaus
2012-12-23  8:08                 ` Dmitry A. Kazakov
2012-12-23 23:38                   ` Shark8
2012-12-24  2:44                     ` sbelmont700
2012-12-24  5:29                       ` Shark8
2012-12-25 21:51                       ` Florian Weimer
2012-12-27  1:00                         ` sbelmont700
2012-12-27  1:47                           ` Randy Brukardt
2012-12-27 14:29                             ` sbelmont700 [this message]
2012-12-27 15:30                               ` Dmitry A. Kazakov
2012-12-27 18:48                                 ` Jeffrey Carter
2012-12-27 21:54                                   ` Randy Brukardt
2012-12-27 22:09                                     ` J-P. Rosen
2013-01-11 11:41                                     ` Yannick Duchêne (Hibou57)
2013-01-11 11:35                                   ` Yannick Duchêne (Hibou57)
2013-01-11 16:13                                     ` Jacob Sparre Andersen
2013-01-12  2:06                                       ` Randy Brukardt
2013-01-11 11:33                                 ` Yannick Duchêne (Hibou57)
2013-01-11 14:15                                   ` Dmitry A. Kazakov
2013-01-11 16:19                                 ` File_Exists (Was: Press Release - Ada 2012 Language Standard Approved by ISO) Jacob Sparre Andersen
2013-01-11 19:36                                   ` Yannick Duchêne (Hibou57)
2013-01-14  5:09                                     ` File_Exists Jacob Sparre Andersen
2013-01-12  7:55                                   ` File_Exists (Was: Press Release - Ada 2012 Language Standard Approved by ISO) Georg Bauhaus
2012-12-27 20:12                             ` compilers, was Re: Press Release - Ada 2012 Language Standard Approved by ISO tmoran
2012-12-27 20:54                               ` Shark8
2012-12-27 22:00                               ` Randy Brukardt
2012-12-27 10:05                           ` Dmitry A. Kazakov
2013-01-11 11:28                           ` Yannick Duchêne (Hibou57)
2013-01-11 14:21                             ` Dmitry A. Kazakov
2013-01-11 14:23                               ` Yannick Duchêne (Hibou57)
2012-12-24  6:44                   ` Yannick Duchêne (Hibou57)
2012-12-24  9:02                     ` Dmitry A. Kazakov
2012-12-24 11:13                       ` Yannick Duchêne (Hibou57)
2012-12-24 15:49                         ` Exception contracts for Ada? Was: " Peter C. Chapin
2012-12-24 16:34                           ` Dmitry A. Kazakov
2012-12-24 19:45                             ` Exception contracts for Ada? Peter C. Chapin
2012-12-25 11:09                               ` Dmitry A. Kazakov
2012-12-27  2:38                               ` Randy Brukardt
2012-12-27  2:16                           ` Exception contracts for Ada? Was: Re: Press Release - Ada 2012 Language Standard Approved by ISO Randy Brukardt
2012-12-27 15:03                             ` Peter C. Chapin
2012-12-27  1:17               ` Randy Brukardt
2013-01-11 17:10       ` Marius Amado-Alves
2012-12-20 21:55     ` Anh Vo
2012-12-21  1:04       ` Bill Findlay
2012-12-18 23:24   ` Randy Brukardt
2012-12-19  8:35     ` Georg Bauhaus
2012-12-19  9:03       ` Dmitry A. Kazakov
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