While CPython still rules on python-dev, especially with the excitement around Py3k, Python's alternative implementations are growing up: PyPy is now capable of running Django, Jython just released version 2.5, and IronPython has been releasing significant milestones like clockwork. I get a lot of satisfaction out of such milestones: they help establish Python as a language you can't ignore, no matter which platform you are using.
Seeing a book like IronPython in Action, by Michael Foord and Christian Muirhead, is another milestone for IronPython. This is a solid work in every aspect, and something nobody using IronPython on .NET should be without. The book is chock full of useful information, presented along with a series of running examples, and covers almost every aspect of IronPython use imaginable.
After reading the table of contents and the introduction by IronPython's creator Jim Hugunin, I couldn't help myself and skipped straight to appendix A, "A whirlwind tour of C#." This is a useful thing to have around for readers like myself who haven't really kept track of things in the .NET world. Maybe I'll comment more on C# another time. For now, let me just say that it seems a decent enough system programming language. The more relevant thing about C# is that you can't avoid learning it if you are developing on .NET, even when using IronPython. There just are too many issues where IronPython has to work around a limitation of C#. This happens often indirectly where a particular API was designed purely with C# in mind. And then there's the issue that Microsoft's API documentation focus on C#. (And VB.NET, I suppose, which after seeing some samples of in this book I have less desire to know than ever.)
There are some introductory chapters -- some fluff about .NET and the CLR, an introduction to Python, and an introduction to with .NET objects from IronPython. The Python introduction has a slight emphasis on differences between IronPython and CPython, though there aren't enough to fill a chapter. This is a good thing! The chapter does a pretty good job of teaching Python, assuming you already know programming. In general, the book is aimed solidly at professional software developers: unless you are paid to do it, why would anyone want to get intimate with Windows?
Yes, Windows programming is what this book is really about. I'm sure that doing Windows programming using IronPython is a much better proposition than Windows programming using C++; but it's still Windows programming. Fortunately the authors maintain a slightly ironic attitude about Windows. I can't help admiring their persistency in getting to the bottom of the many mysteries presented by Windows(and in some cases by IronPython's wrappers).
Many, many years ago -- so long ago that I can't even recall when -- I did some Windows programming myself, using Mark Hammond's Win32 extensions for CPython. That package maps the Win32 API pretty directly to Python. It lets you work with Windows in much the same way as you can in IronPython -- the main difference is that IronPython lives in the more modern .NET world, while Win32 is showing its age.
But is life with IronPython all that much better than in CPython+Win32? It still looks incredibly tedious to create the simplest of UI. Each button in the UI has to be tediously positioned and configured (width, height, padding, font size, etc.). The book maintains a running example throughout many of the chapters, and one of the earlier versions (with many features not yet developed) clicks in at a "mere" 258 lines. Fortunately, the source code for all examples can be downloaded from the book's website. While the downloaded zip file is a whopping 33 megabytes, there's actually only half a megabyte of source code in it (and much of it multiple versions of the same running example) -- the majority of the download is not source code but DLLs that are probably included by the authors because Microsoft scatters them around half a dozen or more different support websites. (Plus, there seem to be multiple copies of IronPython.dll and a few other DLLs included.)
This then, was the big eye-opener for me: that despite all the hype, Windows UI programming is as tedious today as it was in 1995. Sure, the new UI looks a lot better. But that's mostly glitz: 3D effects, color gradients, video, and so on. Sure, it's all object-oriented now. But it hasn't really gotten any less complex to create the simplest of simple UIs. And that's a shame. When is Microsoft going to learn the real lesson about simplicity of HTML? Instead, Microsoft is doing the same thing to HTML that it does to anything it touches: adding cruft to the point where the basic functionality is buried so deeply that most people can't even find it. You can't really blame the average Windows developer for focusing on eye candy instead of usability -- it's all mashed together in the APIs, and by the time you've got something that works at all, you're too exhausted to look at it from your users' perspective.
It's no wonder that users are switching to the web as the platform for everything that used to live on the desktop -- with all its flaws (which I will discuss another time), web development still feels like a breeze compared to Windows development. And that means less time to release, and hence more frequent releases, which in turn means more opportunities for developers to learn what their users actually do. Which as a user I really appreciate.