Design by Contract

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Post #199,132 by Yendor 3/16/05 10:05:14 PM Reply	Design by Contract In Java, that's done via interfaces, for example. -YendorMike "They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." - Benjamin Franklin, 1759 Historical Review of Pennsylvania
Post #199,134 by admin 3/16/05 10:31:01 PM Reply	Not the same thing. DbC is an Eiffel term. Each method has pre and post conditions that must be satisfied (the contract), much like built-in assertions. The contracts can be used for things like proscribing side-effects, etc. Regards, -scott anderson "Welcome to Rivendell, Mr. Anderson..."
Post #199,282 by jake123 3/17/05 5:31:51 PM Reply	That's not strictly Eiffel; They're certainly teaching that to us in my degree in a plethora of our courses, like software specs, application design, etc. --\n-------------------------------------------------------------------\n* Jack Troughton jake at consultron.ca \n [link\|http://consultron.ca\|http://consultron.ca] [link\|irc://irc.ecomstation.ca\|irc://irc.ecomstation.ca] \n Kingston Ontario Canada [link\|news://news.consultron.ca\|news://news.consultron.ca] *\n-------------------------------------------------------------------
Post #199,287 by admin 3/17/05 6:01:57 PM Reply	It's built into Eiffel You can simulate it in Java with AOP, though. Regards, -scott anderson "Welcome to Rivendell, Mr. Anderson..."
Post #199,331 by JimWeirich 3/17/05 11:48:41 PM Reply	It is DESIGN by Contract after all That's not strictly Eiffel; Of course not. I don't think the concept is even original to Eiffel, but Bertrand Meyer certainly took the ideas then refined and developed them. The term "Design by Contract" is coined by Meyer and the Eiffel language is probably the best concrete implementation of DbC in a programming language. However, it is DESIGN by Contract, not CODE by Contract. That's a clue that the concepts apply to something broader than a just a programming language. In fact, it is quite possible to design a system using DbC without ever having direct language support for DbC. -- -- Jim Weirich jim@weirichhouse.org [link\|http://onestepback.org\|http://onestepback.org] --------------------------------------------------------------------- "Beware of bugs in the above code; I have only proved it correct, not tried it." -- Donald Knuth (in a memo to Peter van Emde Boas)
Post #199,494 by jake123 3/19/05 3:09:19 AM Reply	As you say the fact that you don't need specific language support to use the concept when designing an app is sorta my point. It is a very useful design concept, no matter what language you use. --\n-------------------------------------------------------------------\n* Jack Troughton jake at consultron.ca \n [link\|http://consultron.ca\|http://consultron.ca] [link\|irc://irc.ecomstation.ca\|irc://irc.ecomstation.ca] \n Kingston Ontario Canada [link\|news://news.consultron.ca\|news://news.consultron.ca] *\n-------------------------------------------------------------------

Question about exceptions - (drewk) - (31) - March 16, 2005, 04:22:29 PM EST

Lots of discussions about that - (FuManChu) - (6) - March 16, 2005, 04:38:14 PM EST

That only goes for one kind of exceptions! - (CRConrad) - (1) - March 16, 2005, 04:43:24 PM EST

What does the "checked" mean to you? - (FuManChu) - March 16, 2005, 05:55:46 PM EST

But he's saying that you should use both - (drewk) - (3) - March 16, 2005, 05:18:00 PM EST

My rule of thumb is, - (Arkadiy) - March 16, 2005, 05:40:27 PM EST

Pick one and stick with it. - (admin) - March 16, 2005, 06:04:02 PM EST

You can do both (or more accurately: either) with or without - (FuManChu) - March 16, 2005, 06:05:51 PM EST

Re: Question about exceptions - (JimWeirich) - (23) - March 16, 2005, 07:35:00 PM EST

Nice point about responsibility, but grey areas abound - (FuManChu) - (11) - March 16, 2005, 07:46:02 PM EST

Re: Nice point about responsibility, but grey areas abound - (JimWeirich) - (10) - March 17, 2005, 03:30:15 PM EST

No, we don't - (drewk) - (9) - March 17, 2005, 05:25:32 PM EST

The difference is simple - (ben_tilly) - (8) - March 17, 2005, 05:57:25 PM EST

Problem with that - (drewk) - (4) - March 17, 2005, 06:13:50 PM EST

See? Whether it is an error IS ambiguous! -NT - (ben_tilly) - (2) - March 17, 2005, 06:19:06 PM EST

I think I know what to do then - (drewk) - (1) - March 17, 2005, 06:28:16 PM EST

Exactly -NT - (ben_tilly) - March 17, 2005, 06:59:56 PM EST

Re: Problem with that - (JimWeirich) - March 17, 2005, 11:59:18 PM EST

Thats the sort of logic that makes me wary of exceptions. - (static) - (2) - March 17, 2005, 08:18:40 PM EST

Exceptions are one form of Continuation - (ChrisR) - (1) - March 17, 2005, 10:33:45 PM EST

Icon's generators rely on the failure model. - (static) - March 18, 2005, 01:24:49 AM EST

Disabling assertions - (ChrisR) - (3) - March 16, 2005, 07:52:17 PM EST

That's one of the points he raised - (drewk) - (2) - March 16, 2005, 08:59:04 PM EST

Expense is relative - (ChrisR) - March 16, 2005, 11:52:33 PM EST

Re: That's one of the points he raised - (JayMehaffey) - March 17, 2005, 08:31:12 AM EST

DbC? -NT - (drewk) - (6) - March 16, 2005, 09:32:24 PM EST

Design by Contract - (Yendor) - (5) - March 16, 2005, 10:05:14 PM EST

Not the same thing. - (admin) - (4) - March 16, 2005, 10:31:01 PM EST

That's not strictly Eiffel; - (jake123) - (3) - March 17, 2005, 05:31:51 PM EST

It's built into Eiffel - (admin) - March 17, 2005, 06:01:57 PM EST

It is DESIGN by Contract after all - (JimWeirich) - (1) - March 17, 2005, 11:48:41 PM EST

As you say - (jake123) - March 19, 2005, 03:09:19 AM EST

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