From: Niklas Holsti <niklas.holsti@tidorum.invalid>
Subject: Re: Implicit actions & program correctness
Date: Tue, 26 May 2020 11:47:36 +0300
Date: 2020-05-26T11:47:36+03:00 [thread overview]
Message-ID: <hj43d9F2cl7U1@mid.individual.net> (raw)
In-Reply-To: <87o8qb7ikc.fsf@nightsong.com>
On 2020-05-26 1:31, Paul Rubin wrote:
> deadhacker <gstover@gmail.com> writes:
>> Sadly, his Java API is no longer available, so I can't see how he
>> solved it.
>> Do you (or anyone else here) know how it could be solved with Ada?
>
> I didn't look at the Java code (don't know if it was posted somewhere)
> but I'd expect it is done with Java classes and subclasses. You'd have
> a class for game state, and container (wrapper) classes for "initial",
> "non-initial", "finished", and "non-finished". Each wrapper would
> either be empty, or contain a state of the specified type.
>
> The "move" function would accept a non-finished state as a parameter,
> and return three maybe-empty wrapper objects containing the new state.
> To call "move" again you'd have to look in the "non-finished" wrapper to
> get a non-finished state from it, in the event that there is one. If
> the non-finished wrapper is empty, then the game is finished and there
> is no way to call "move" again. Similarly with takeback, etc.
That, of course, is basically a run-time check, and not a compile-time
check as was originally desired. But as for Ada, program-proving tools
could be applied at compile-time to verify that the program does check
(at run-time) if "move" can be called again.
--
Niklas Holsti
niklas holsti tidorum fi
. @ .
next prev parent reply other threads:[~2020-05-26 8:47 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-15 17:45 Implicit actions & program correctness deadhacker
2020-05-15 17:55 ` deadhacker
2020-05-15 18:27 ` Nasser M. Abbasi
2020-05-15 19:01 ` Paul Rubin
2020-05-15 19:03 ` Jeffrey R. Carter
2020-05-15 20:13 ` deadhacker
2020-05-15 22:09 ` Paul Rubin
2020-05-25 20:15 ` deadhacker
2020-05-25 20:36 ` Niklas Holsti
2020-05-25 22:31 ` Paul Rubin
2020-05-26 8:47 ` Niklas Holsti [this message]
2020-05-26 9:55 ` Paul Rubin
2020-05-16 13:52 ` Brian Drummond
2020-05-16 10:10 ` Niklas Holsti
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