Re: PAR (Was: Embedded languages based on early Ada)

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Tue, 6 Mar 2007 17:49:32 -0600, Randy Brukardt wrote:

> "Dr. Adrian Wrigley" <amtw@linuxchip.demon.co.uk.uk.uk> wrote in message
> news:pan.2007.03.06.13.19.20.336128@linuxchip.demon.co.uk.uk.uk...
> ...
>> One aspect of this discussion is the inaccessability of fine-grain
>> concurrency to either a harware developer or a software developer.
>> As a processor designer, I can see how to implement concurrent
>> calls and concurrent memory access - but doing this does not help
>> run any existing code.  As a programmer, I can see where my code
>> is logically concurrent, but the language denies me this expressiveness,
>> and my processor doesn't support it.  Some leadership is needed!
> 
> Exactly my point; by allowing this to be written and then mapped
> conventionally, programmers can get used to the idea of specifying
> fine-grained parallelism (preferably with checking!), without having to
> invest in all new (and thus buggy) systems.

Hmm, but checking is really the key issue here. I fail to see it in bare
PAR. It is just absent there. What would be the semantics of:

declare
   I : Integer := 0;
begin in parallel
   I := I + 1;
   I := I - 1;
end;  -- What is the postcondition here?

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