Book review: Professional F# 2.0

In one of my last posts I wrote about a F# application written test first. While working on this application I read the book 'Professional F# 2.0' from Wrox. Personally I believe the Wrox books are most of the time the best books you can find on a subject, especially their 'Professional' series.They go very deep into each subject and give you all the details you need to know. So here is what I think about the Professional F# book, by Ted Neward, Aaron Erickson, Talbott Crowell and Rick Minerich.

The book begins with an extensive explanation of the different F# language constructs you can use. The same explanation you would get in a typical C# book, in fact. While this section gives you all the necessary language details: what types look like in F#, how certain constructs, like ifs and whiles, need to be written. It lacks, however, the basic explanation of how a language like F# should be used. As a reader you don't get much of a clue why these kinds of constructs might be useful. The few points where you do get some extra info on the style in which to write F# code, a reader without any knowledge of functional programming, will be nonplussed about why certain things are done in a certain way. That really is a shame, because I think a lot of readers will drop off once they see the extensive differences in language constructs they need to overcome when coming from a more traditional language.

I was hopeful though that in 'Part III: Functional Programming' there would actually be some good information about how to program using a functional style. But alas, again the author goes on and on about language constructs, what functions look like and how you write them, not how you use them properly. Some more advanced topics also come into play, like closures. Not that this is so extremely advanced, but it is a concept you don't hear every day, you use it quite often, though, even in C#, but you don't always think of it as being a closure. The explanation the author gives for the closure concept, however, is quite difficult to understand, up to the point where I had to use Google to get the right explanation. Same goes for the principle of currying, which, in my opinion, is explained the wrong way.

As for the F# language itself, it adds quite a lot of special constructs you do need to get used to. Especially when writing your first F# program, be sure to have a language reference nearby. For such a reference, this book is ideal. It explains all the little tidbits you need to know. But still, in my opinion, F# adds a lot of unnecessary language constructs. When you are, for instance, defining a recursive function, you are obliged to use the rec keyword, otherwise the compiler won't allow you to call yourself. Coming from a Lisp kind of language, this adds noise to your code (although I have to admit Scheme has its own weird language constructs).

Since this book was quite a disappointment for me, I would gladly like to guide you to some other useful resources:

• The MSDN library will not be of much help. It will give also you a lot of info about the language, as this book does, but it doesn't say much about the programming style to use. What you can find on the MSDN site, however is how to get started setting up your first F# project in Visual Studio. This was something I struggled with in the beginning of programming F#, how a project is structured.
• Tryfsharp: This site by the Microsoft research team lets you go through an interactive tutorial in which you can immediately try out different examples in an F# interactive console. In their tutorial they explain all the important F# constructs that are different from the other programming languages you come across (without too much other explanatory crap that you do not need to know). The examples given are also quite easy to follow (with some small exceptions). The examples given were also quite close to the examples you will find in introductory books on functional programming style. This site is based on the book 'Programming F#' by Chris Smith (O' Reilly). I actually good much better information on this site than in the Wrox book.
• fsharp community samples: These can be found at codeplex. You can find some samples here, but also quite some links to other resources and blogs. Good starting place, if you ask me.
• F# wikibook: Explains not only the basic concepts, but also some advanced topics such as advanced data structures in F#, which, after you've gone through the introductory stuff are quite useful.

With all this material I now hope to get a better Game Of Life written. I will probably throw away what I already have and not try it with a class, but with only functions. We'll see where this ends.