David Simcha's std.parallelism

[Andrei Alexandrescu]

I think David Simcha's library is close to reviewable form. Code:

http://dsource.org/projects/scrapple/browser/trunk/parallelFuture/std_parallelism.d

Documentation:

http://cis.jhu.edu/~dsimcha/d/phobos/std_parallelism.html

Here are a few comments:

* parallel is templated on range, but not on operation. Does this affect 
speed for brief operations (such as the one given in the example, 
squares[i] = i * i)? I wonder if using an alias wouldn't be more 
appropriate. Some performance numbers would be very useful in any case.

* Why is ThreadPool a class and what are the prospects of overriding its 
members?

* Can't we define the behavior of break inside a parallel loop?

* I think it does make sense to evaluate a parallel map lazily by using 
a finite buffer. Generally map looks the most promising so it may be 
worth investing some more work in it to make it "smart lazy".

* waitStop() -> join()?

* The documentation should use more examples. Currently it uses entities 
without defining them (Task, TaskPool etc.)

* why runCallable()? There's no runUncallable().

* Should there be a makeAngel to undo makeDaemon?

Overall, to prepare this for the review process, the documentation 
should be grown considerably with motivating examples and relevant 
benchmarks. We are modeling our review process after 
http://www.boost.org/community/reviews.html. The first realization of 
the process has been for std.datetime, and it seems to have been a success.


Andrei