In this chapter, we cover some simple interactive programming with F# and .NET. By now you should have downloaded and installed a version of the F# distribution as described in Chapter 1. In the sections that follow, we use F# Interactive, a tool you can use to execute fragments of F# code interactively and a convenient way to explore the language. Along the way, you'll see examples of the most important F# language constructs and many important libraries.
Listing 2-1 shows your first complete F# program. You may not follow it all at first glance, but we explain it piece by piece after the listing.
Listing 2-1. Analyzing a String for Duplicate Words
#light /// Analyze ...