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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: SI Units Checked and Unchecked
Date: Thu, 9 Aug 2018 16:07:21 +0200
Date: 2018-08-09T16:07:21+02:00	[thread overview]
Message-ID: <pkhhqo$4d8$1@gioia.aioe.org> (raw)
In-Reply-To: d628e94f-7ea0-4616-96a9-eb28ff6c9d6e@googlegroups.com

On 2018-08-09 15:47, Dan'l Miller wrote:

> Shouldn't the •entire• point of a units-of-measurement library (or feature of language) be compile-time errors, not run-time exceptions/errors.

No, because in most cases the unit is unknown. Consider a widget library 
with instruments indicating dimensioned values, dimensioned calculator, 
serialization of dimensioned data etc.

What is necessary but not sufficient is language support for handling 
statically known constraints using compile-time static operations and 
removing statically known discriminants from the representation.

Note a direct analogy with classes for scalar types. Type tag is in 
essence just a discriminant. For some types we want static discriminants 
and other constraints removed.

> I would be interested in a summary (or even better, an AI) that itemizes all the core-language obstacles in currently-standardized Ada to moving all the incompatible usages of units to be compile-time errors instead of raising exceptions.

The Ada type system is not capable to handle dimensioned types. I posted 
a list of requirements for a dimensioned types support some years ago here.

There are lots of language issues to resolve first before approaching 
dimensioned types.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de


  reply	other threads:[~2018-08-09 14:07 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-09 12:44 SI Units Checked and Unchecked AdaMagica
2018-08-09 13:47 ` Dan'l Miller
2018-08-09 14:07   ` Dmitry A. Kazakov [this message]
2018-08-09 15:03     ` Dan'l Miller
2018-08-09 15:51       ` Dmitry A. Kazakov
2018-08-09 17:32         ` Dan'l Miller
2018-08-09 19:42           ` Dmitry A. Kazakov
2018-08-09 22:12             ` Dan'l Miller
2018-08-10  6:45               ` Dmitry A. Kazakov
2018-08-10 13:59                 ` Dan'l Miller
2018-08-10 14:50                   ` Dmitry A. Kazakov
2018-08-10 17:04                     ` Dan'l Miller
2018-08-10 17:34                       ` Dmitry A. Kazakov
2018-08-11  4:42                         ` Paul Rubin
2018-08-11  5:46                           ` Dmitry A. Kazakov
2018-08-11 19:57                             ` Paul Rubin
2018-08-11 21:01                               ` Dmitry A. Kazakov
2018-08-09 18:47       ` Paul Rubin
2018-08-09 19:13         ` Dan'l Miller
2018-08-09 14:31   ` AdaMagica
2018-08-09 15:19     ` Dan'l Miller
2018-08-09 16:07 ` Jeffrey R. Carter
2018-08-09 17:41   ` AdaMagica
2018-08-09 20:34     ` Jeffrey R. Carter
2018-08-10  9:13       ` AdaMagica
2018-08-10 20:20         ` Jeffrey R. Carter
2018-08-13  8:57           ` AdaMagica
2018-08-20 17:55             ` AdaMagica
2019-09-04 14:20 ` Shark8
2019-09-04 17:11   ` AdaMagica
2019-09-06 21:01     ` Shark8
2020-08-13 12:24       ` SI Units Checked and Unchecked - Completela overhauled version AdaMagica
  -- strict thread matches above, loose matches on Subject: below --
2003-02-05  7:03 SI Units Checked and Unchecked Grein, Christoph
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