From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Proposal: Auto-allocation of Indefinite Objects
Date: Sun, 23 Aug 2020 14:29:14 +0200 [thread overview]
Message-ID: <rhtneo$u89$3@gioia.aioe.org> (raw)
In-Reply-To: rhssee$ar5$1@franka.jacob-sparre.dk
On 23/08/2020 06:48, Randy Brukardt wrote:
> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message
> news:rhnqjf$bga$2@gioia.aioe.org...
>> On 21/08/2020 01:30, Randy Brukardt wrote:
> ...
>>> There's no reason that a compiler couldn't "build-in" a simple bounded
>>> vector container as the basic building block.
>>
>> That simply replaces the word "array" with four words "simple bounded
>> vector container." The construct is still there and it is still built-in.
>> The syntax and usability are drastically worse, though.
>
> ??? The syntax of use is the same (as it is in Ada 2012). Declaration would
> be an instance,
That alone disqualifies it in my eyes.
> about the same length and wordiness as an array declaration.
Plus a dozen of tagged helper types...
> Yes, junk like slices, settable/retrievable bounds, and built-in operations
> that are rarely used would be gone, but so would the rather substantial
> overhead that those things entail. There'd be a lot more flexibility in
> implementation, which would allow better implementations.
These is a vital part of array interface to me. Moreover I want lost of
other junk there, like ranges being proper types, like multidimensional
slices/subarrays, indicator sets (to specify array's diagonal) etc.
> Virtually every array that I write has a fixed size (capacity really) and a
> usage high-water mark (a "length"). Having that generated automatically
> would be usually better than having to reinvent it literally every time I
> program something. (And as you've noticed repeatedly, Ada's type abstraction
> isn't good enough to make it practical to build anything reusable to do
> that.)
I agree with that, but disagree with the solution. In my view arrays
must be 1) generalized, 2) abstracted to support user-defined
implementations.
The challenge is to have a type system where one could design a 3-band
matrix type usable where a dense matrix type is expected.
>>> One could do something similar for records, although I would probably
>>> leave
>>> them as in Ada and just allow user-definition of "." (via a getter/setter
>>> pair).
>>
>> Ditto.
>
> ???
>
> The basic idea would be to eliminate the huge number of special cases that
> exist in Ada resolution and essentially make *everything* a subprogram call
> at it's heart.
Yes, I agree everything must have a corresponding primitive operation.
But there are cases when such operations must be static like "." of a
record types or implemented per delegation to a generalized
implementation like integer or string literals.
> Ada did that for enumeration literals and that model makes
> sense for pretty much everything: object usage, indexing, selection, etc. It
> would be much easier to prove that resolution is doing the right thing (I
> don't think that would be practically possible for Ada).
I think that not only Ada's, but even C++'s type system, could be
expressed by means of a more powerful one. After all it is possible to
write a compiler for both...
--
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de
next prev parent reply other threads:[~2020-08-23 12:29 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-03 22:48 Proposal: Auto-allocation of Indefinite Objects Stephen Davies
2020-04-03 23:45 ` Stephen Leake
2020-04-04 10:54 ` Jeffrey R. Carter
2020-04-04 20:55 ` Stephen Davies
2020-04-04 8:31 ` Dmitry A. Kazakov
2020-07-27 7:47 ` Yannick Moy
2020-07-27 9:21 ` J-P. Rosen
2020-07-27 9:49 ` Dmitry A. Kazakov
2020-07-27 17:48 ` Brian Drummond
2020-07-27 20:02 ` Dmitry A. Kazakov
2020-07-28 14:28 ` Brian Drummond
2020-07-28 14:59 ` Dmitry A. Kazakov
2020-07-29 15:33 ` Brian Drummond
2020-07-29 16:20 ` Dmitry A. Kazakov
2020-07-30 13:37 ` Stephen Davies
2020-07-30 14:23 ` Dmitry A. Kazakov
2020-07-30 17:04 ` Brian Drummond
2020-07-30 18:28 ` Dmitry A. Kazakov
2020-08-10 0:39 ` Randy Brukardt
2020-08-10 8:57 ` Dmitry A. Kazakov
2020-08-20 0:10 ` Randy Brukardt
2020-08-20 17:49 ` Dmitry A. Kazakov
2020-08-20 20:19 ` Dennis Lee Bieber
2020-08-20 23:33 ` Randy Brukardt
2020-08-21 6:45 ` Dmitry A. Kazakov
2020-08-23 4:52 ` Randy Brukardt
2020-08-23 12:28 ` Dmitry A. Kazakov
2020-08-20 23:30 ` Randy Brukardt
2020-08-21 6:46 ` Dmitry A. Kazakov
2020-08-23 4:48 ` Randy Brukardt
2020-08-23 12:29 ` Dmitry A. Kazakov [this message]
2020-08-10 0:31 ` Randy Brukardt
2020-08-10 8:58 ` Dmitry A. Kazakov
2020-08-20 0:13 ` Randy Brukardt
2020-08-20 17:49 ` Dmitry A. Kazakov
2020-08-20 23:25 ` Randy Brukardt
2020-08-21 7:08 ` Dmitry A. Kazakov
2020-08-23 5:03 ` Randy Brukardt
2020-08-23 12:28 ` Dmitry A. Kazakov
2020-07-27 20:31 ` Jeffrey R. Carter
2020-07-31 9:25 ` Stephen Davies
2020-07-31 10:20 ` Dmitry A. Kazakov
2020-08-01 11:22 ` Stephen Davies
2020-08-01 12:58 ` Dmitry A. Kazakov
2020-08-01 20:35 ` Stephen Davies
2020-08-01 20:56 ` Dmitry A. Kazakov
2020-09-03 4:30 ` linda white
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