In the comments section to an earlier post Göran Krampe brought up some excellent points, backed by experience, on my remark that more dynamic languages increases risk in projects, especially if all developers in the project are not on the same level. Here are some of my comments on those, but please do read Göran’s entire comment for more context. Since I find the discussion to be very interesting, I thought I’d bring it up as a new article.
Just read your article at IDG regarding Alan Kay/Smalltalk – and it was good. For once not a single glaring misconception regarding Smalltalk 🙂 – I am a bit jaded by all people throwing around ”truths” about Smalltalk without having actual experience themselves. So kudos for that. 🙂
Thank you! However, I must confess that my Smalltalk experience is limited to playing around with Squeak in my spare time, so I have never used it in a large project. Bear this in mind when you read my response…
Above though it sounds like you are saying that Java would mean a lower risk than Smalltalk for larger projects or projects in which the developers are of ”average” or ”mixed” level. That I definitely do NO agree with on the other hand. 😉
So my experience is the exact opposite. I claim that less experienced developers can more easily be made productive in Smalltalk than in Java. I have repeatedly taught OO *and* the basics of Smalltalk in a single day including practice and then had these pupils find bugs and complement a working small system the next day.
I suspected that a smalltalker might not agree with that 🙂 Please not that I’m only talking about risk, not programmer effiency. Risk isn’t inherently bad, since it usually goes hand in hand with opportunity. Your points about new programmers learning Smalltalk quicker than Java is obviously backed up by experience, but a little beside the point.
The reason that I feel projects done in more dynamic environments (I’m going to lump Smalltalk, Python and Lisp together here, which might not be entirely fair) to have a higher level of risk is that the dynamic properties of the language will allow your system to take on aspects of a domain specific language, especially if some members of your team understands the Zen of Smalltalk/Lisp/Python. For example, in both Lisp and Smalltalk you can essentially redefine parts of the syntax, like the if/then/else statements, and if it makes sense in your design, you might very well want to do that. But if another programmer, who has yet to be enlightened (sticking with the Zen theme) on the expects the syntax to work like default, this might trip him up (Operator overloading in C++ and .Net gives us essentially the same problem). This risk increases if the programmer has been taught more traditional imperative programming in the style of Java/C# and have not been given a good introduction to Smalltalk.
Things like tail recursion, higher order functions, metaclasses and even polymorphism cam be difficult to wrap your head around, especially since you can get a lot of stuff done without them, and in not-so-dynamic environments, you usually do.
Or to put it more soundbite-friendy way: The more dynamic and open-ended a language is, the more choices you have at any given time. Every choice introduces opportunity — and risk.
However, since I haven’t done any large projects in either Smalltalk or Lisp (I did a elevator control system in Scheme in school, though :-)), maybe my opionions should be taken with a grain of salt. I’d be happy to hear your opinions on why the things I’ve mentioned above aren’t such big risk factors after all.
Also, the idea that there is something inherent in Smalltalk making it unsuitable for large scale development is simply not true either. And there is ample evidence for that.
There are very large systems having been built in Smalltalk with great success over a long period of time. And I mean *large*. 14000 classes, 65 developers/staff, 500 users etc, see for example the ”Kapital” system at JP Morgan Bank, https://secure.cwheroes.org/briefingroom_2004/pdf_frame/index.asp?id=4909)
I don’t think I’ve implied anything like that. It is interesting to hear about these big successful projects, but I keep wondering why we don’t hear more about them. Paul Graham published an essay about how good Lisp was for building ViaWeb, and most people that are familiar with XP has at least heard about the C3 project, but there must be more stories, right?
The point of my column that started the debate was that while many of the inventions and discoveries that come from the Smalltalk community are now used everywhere (MVC, JIT, design patterns…, XP), the language itself isn’t. I don’t believe it’s as simple as Sun and Microsoft having a larger marketing budget, but I’m very interested in a discussion of what the real reason could be, as I still think there are more that the general programmer community could learn from Smalltalk.