Mark Mullin wrote:
> 
> OK, I've gone and put my foot in it, I make one or two little comments about
> iterators and people just jump all over my case   :-)
> 
> What I mean to say is that for iterated collections such as ordered
> collection, the process of adding and searching the collection is
> significantly more expensive than in a lower level compiled language such as
> C++.  I'm not denying the benefits of 1st class oop, garbage collection, or
> all the other great things I get, I'm just observing on a performance
> number.

Understood.  I'd just have to pipe in along with Bijan that, when doing basic collection operations and looping, I'd say the term "horrible" would be reasonable to describe the usability/convenience of (explicit) Java/C++ iterators relative to the implicit iteration in Smalltalk.

In Java/C++, iterating through a collection requires setting up an explicit Iterator object which often involves 3-4 times the amount of code of the Smalltalk equivalent, especially when you consider select:, collect:, detect:, etc.  In dealing with Java every day, this is probably at or near the top of the list of things that slow down my productivity.  (Up there with the primitive types problem.  Maybe I just deal with Collections a lot.)  This article describes the issue pretty well:  http://softwaredev.earthweb.com/java/sdjjavase/article/0,,12395_628951,00.html

But yeah, performance is a different issue.

> What this means in using Squeak is that you can't opt out to the C++ dumb
> ass solution of "I got a list of 10K items, I'll just grovel through them to
> find the one I want."  What is ignorable in C++ is a slow mover in
> Smalltalk.

I think much of the problem is that some collection operations just haven't really been optimized much in Squeak yet.  For example, Scott Crosby recently did some work with vastly improving the performance of large Sets... this stuff will hopefully make its way into 3.3alpha in one form or another.

Some other Smalltalks such as VisualWorks have had most of their collection operations pretty well optimized, so it's not necessarily a language problem.  Generally, I'd expect this situation in Squeak to improve as more people do real work with larger collections.

- Doug Way
  dway at riskmetrics.com