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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Generators/coroutines in future Ada?
Date: Wed, 12 Jul 2017 09:27:28 +0200
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Xref: news.eternal-september.org comp.lang.ada:47374
Date: 2017-07-12T09:27:28+02:00
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On 12/07/2017 07:35, Randy Brukardt wrote:
> "Victor Porton" <porton@narod.ru> wrote in message
> news:ok3meg$fg6$1@gioia.aioe.org...
>> Dmitry A. Kazakov wrote:
>>
> ....
>>>> A task is a perfect abstraction for a thread of control that maintains
>>>> its own execution state!
>>>
>>> Except that no control is required.
>>>
>>> I don't understand what is wrong with:
>>>
>>>      type Stateful is limited private;
>>>      function Generate (X : not null access Stateful) return Things;
>>
>> The thing "wrong" with this, is that it is sometimes hard to implement
>> Generate(). In Python this can be done in an easier way by using
>> generators
>> (Python's "yield" keywords).
> 
> The thing "wrong" with this is that it forces sequential execution.

Some algorithms, protocols in particular, are sufficiently easier and 
clearer to implement in a sequential manner: fetch data, wait, react, 
repeat. Ada tasks is an ideal abstraction for this except for being too 
heavy weight for certain applications.

> The coming problem with "classic" programming languages like Ada is that
> they don't map well to architectures with a lot of parallelism.

Rather the opposite. Parallel architectures do not map well to any 
reasonable programming language. The thing is hard no matter how you 
approach it.

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