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From: Georg Bauhaus <nonlegitur@futureapps.invalid>
Subject: Re: Why doesn't Ada allow user-defined attributes?
Date: Fri, 21 Jul 2017 17:11:28 -0000 (UTC)
Date: 2017-07-21T17:11:28+00:00	[thread overview]
Message-ID: <oktcjv$liq$1@dont-email.me> (raw)
In-Reply-To: oks9ab$hao$1@gioia.aioe.org

Dmitry A. Kazakov <mailbox@dmitry-kazakov.de> wrote:
> On 21/07/2017 06:46, Georg Bauhaus wrote:
> 
>> Do you really need 'Length?
> 
> Sure, when for example the result depends on the number of elements. 

Count is computed easily, albeit inefficiently, or even efficiently
whenever a collection type caches its number of elements.
So, is 'Length, if not a static property, more than a prim op?

> 'Length is a general property of any container (set).
> 
>> It seems an implementation detail whenever the language doesn't have forall
>> or exists.
> 
> Enumeration requires some additional assumptions, stronger than length.

What real thing can be counted yet not one by one?


  reply	other threads:[~2017-07-21 17:11 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-07-20  0:02 Why doesn't Ada allow user-defined attributes? Shark8
2017-07-20  9:34 ` Brian Drummond
2017-07-20 16:07   ` Shark8
2017-07-21  4:46     ` Georg Bauhaus
2017-07-21  7:08       ` Dmitry A. Kazakov
2017-07-21 17:11         ` Georg Bauhaus [this message]
2017-07-21 19:39           ` Dmitry A. Kazakov
2017-07-22 16:33             ` G.B.
2017-07-22 20:12               ` Dmitry A. Kazakov
2017-07-23  6:41                 ` G.B.
2017-07-23  8:22                   ` Dmitry A. Kazakov
2017-07-24 17:52                     ` G.B.
2017-07-20 18:53 ` Randy Brukardt
2017-07-20 23:58 ` Matt Borchers
2017-07-21  7:14   ` Simon Wright
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