F Sharp Programming/Preface

F# : Preface

How This Book Came To Be

Note to contributors: normally a preface is written by the author of a book. Since this book might have several authors, feel free to write your own preface.

Written by Awesome Princess: Normally, authors choose to write a preface to a book about the book itself. But, just because I'm an egomaniac, I want to write about myself instead. Not because I'm an especially interesting person, but because my experiences with functional programming are relevant to the creation of this book.

So, in 2006, I was becoming bored with my job. The only kind of software I've ever written has been software that puts a GUI interface on top of a database, and I just became tired with it. I wanted to find an interesting programming job.

Just for fun, I started looking at job openings at different high tech companies (Google, eBay, Microsoft, Amazon, etc.). I noticed that all of the boring jobs—CRUD apps, simple web development—wanted programmers with Java, C#, or C++ experience. The interesting jobs—compiler programming, digital circuit verification, massively parallel computing, biometrics—sought programmers with experience in weird and unfamiliar languages. In particular:

• I read in Paul Graham's article Beating the Averages that the first version of Yahoo! Store was written largely in Lisp
• I came across job postings for Google looking for programmers with Haskell or Python experience in addition to C++.
• I read in an Erlang FAQ that the Erlang programming language is the tool of choice for telecommunications providers like T-Mobile.
• I've heard for years that Lisp was a niche language during the Golden Age of AI research.
• I ran across numerous Microsoft job postings in the area of driver verification looking for OCaml programmers.

The most remarkable applications in the world aren't written in Java; they're written in these weird, obscure languages. More interestingly, the languages in the highest demand—Erlang, Haskell, Lisp, OCaml—were all functional programming languages, a wholly alien programming paradigm from my vantage point deep in C#-Land. I decided to supplement my programming wisdom by learning one of these obscure functional programming languages.

The choice between one language or another wasn't too hard to make. If I'm going to learn a new language, it needs to satisfy a few conditions: it should be practical enough for personal use, relatively speedy, useful to employers, and impress my friends when I tell them I learned a weird new language. Haskell was quite scary to me at the time, and I can't really exploit Erlang's concurrency with the tiny scope of the apps I write for myself. The choice came down to Lisp and OCaml; based on these comparisons of different languages, I decided that OCaml's static-typing, speedy native code, tiny compiled binaries, and established niche in the financial market made it a good choice for me.

I learned OCaml and it completely changed my way of thinking. After using the language and keeping up with OCaml newsgroups, I heard about a .NET port of OCaml called F#. I figured I already knew the .NET BCL inside and out, and I was already familiar with OCaml, I could probably learn this language pretty quickly.

In August 2007, I took the time to get familiar with the F# language. While I picked up most of it fairly well, one thing I noticed about the language was how completely inaccessible it was to people trying to learn the language. The complete dearth of F# material out there just makes it impossible for beginners to learn F# as their first language. Even today, November 2008, there are only a handful of publications, but even as a person with many years of programming experience, I struggled to follow along and comprehend the language.

For a long time, I wanted to write something that would actually be useful to F# neophytes, something that would contain everything anyone needs to know about the language into a single comprehensive resource. This book was originally started by a fellow Wikibookian in 2006, but no one had written any substantial content for it for nearly 2 years. I found this book and decided that, for the sake of people wanting to learn F#, I'd compile everything I knew about the language into a format that would be acceptable for first-time programmers.

I am happy with the way the book has been progressing. Ultimately, I'd like people to link to this book as the preferred, definitive F# tutorial on the Internet.