• bearophile (10/11) Sep 29 2009 The following is a quote from the transcript of this:
• Walter Bright (2/5) Sep 29 2009 D's scope statement specifically addresses transactional safety.
• language_fan (4/10) Sep 30 2009 Indeed, maybe SPJ should just retire as D solves all problems wrt

bearophile <bearophileHUGS lycos.com> writes:

The following is a quote from the transcript of this:
http://www.infoq.com/interviews/armstrong-peyton-jones-erlang-haskell

(To see the whole transcript click on the "show all" button, and then select
"no style" if you use Firefox).

This part of the dialogue shows a possible usage for pure (or more pure)
languages: to correctly implement, avoiding to go mad, very tricky
transactional algorithms.

In such situations the limiting factor is not the CPU nor the amount of
programmer's time spent on the code (so both C and Python are unfit), but it's
the brain of the programmer, because such algorithms are so tricky and complex
that the problem is to understand them (enough to produce a correct
implementation).

So a multi-purpose and multi-paradigm language (like Scala, and maybe future
D2) can try to become fit for those purposes too (maybe not as fit as Haskell &
Co. but fit enough for smaller similar purposes). In such situations
performance is not the most important thing, as it's not important for the
language to be handy and quick to write. What's useful is to have a language
that keeps sides effects to the minimum allowing to create the more isolated
subsystems as possible. I don't know if you can create such purer subsets into
general languages like Scala/D2, but I think it may be doable.

Suddenly people want to know how to write distributed programs, which they
never wanted to do before. So, how do you do distributed transactions? How do
you do consistency? It was always a pretty obscure part of computer science,
these distributed algorithms. Then we said "We've got these to do parallel. How
the heck do we program these things?" In Erlang or Haskell, these algorithms
are just difficult, but in other languages they are...

SPJ: Downright impossible!

JA: Yeah, right! I mean even if you have a very clean, pure programming
language and you take Paxton algorithms or something like that, they are
complicated things. They make your head hurt. There is a whole branch of
mathematics, a whole branch of computer science to understand distributed
algorithms and they live at the bottom of these social networks and things,
ticking along. So I don't think you are going to see Erlang replacing
Javascript or anything like that in browsers, but where you are seeing them
being deployed is in the infrastructures, in the clouds and things like that,
to glue the bits together properly, because that's where you need the complex
algorithms. We are seeing an infrastructure-building things, cloud computing
and what you are doing inside modern massive multicores, how do you organize
computations. There where it's being used a lot.<

Bye,
bearophile

Walter Bright <newshound1 digitalmars.com> writes:

bearophile wrote:
 This part of the dialogue shows a possible usage for pure (or more
 pure) languages: to correctly implement, avoiding to go mad, very
 tricky transactional algorithms.

D's scope statement specifically addresses transactional safety.

language_fan <foo bar.com.invalid> writes:

Tue, 29 Sep 2009 18:15:27 -0700, Walter Bright thusly wrote:

 bearophile wrote:
 This part of the dialogue shows a possible usage for pure (or more
 pure) languages: to correctly implement, avoiding to go mad, very
 tricky transactional algorithms.

 
 D's scope statement specifically addresses transactional safety.

Indeed, maybe SPJ should just retire as D solves all problems wrt 
transactions. D2 also has a purely functional subset called SafeD which 
effectively replaces his modest brainchild, Haskell.