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Re: Sun Fortress and Perl 6

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From:
Autrijus Tang
Date:
April 27, 2005 02:04
Subject:
Re: Sun Fortress and Perl 6
Message ID:
20050427090401.GA1720@aut.dyndns.org
On Wed, Apr 27, 2005 at 08:21:27AM -0000, Rafael Garcia-Suarez wrote:
> Autrijus Tang wrote in perl.perl6.language :
> >
> > 4. Software Transaction Memory
> > In Fortress, there is also an `atomic` trait for functions, that
> > declares the entire function as atomic.
> 
> Interesting; and this rolling-back approach avoids the deadlock issues
> raised by the use of semaphores (like in Java's synchronization
> approach).
> 
> But, as the slides point out, you can't do I/O or syscalls from an
> atomic function; and in Haskell you can ensure that with the wise use of
> monads. Perl 6 has no monads, last time I checked...

In Haskell there is an unsafeIOtoSTM call that lets you do IO inside
the atomic function; it's just that the IO is unsafe; it will be run
repeatedly and cannot be rolled back.

I can certainly see a `is pure` trait on Perl 6 function that declares
them to be safe from side effects.  In a sense, `is const` also does that.

Thanks,
/Autrijus/

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