F#: Do more with less coding

BANGALORE, INDIA: Most scientists use mathematics as a language to define their models. Since long, these scientists have been trying to bridge the gap between scientific or mathematical models and the executable code. Functional programming language allows developers to write programs that are close to the mathematical models.

F# is a functional programming language for .NET framework. This strongly typed language uses type inference, which means data type need not be explicitly declared by programmers; instead they are declared by the compiler during compilation.

F# takes best features of both imperative and declarative programming paradigms making it a language both scientists and programmers can identify with. It tries to facilitate a mathematician become a better programmer and vice versa. It also combines the power of declarative languages popular with scientists such as Ocaml and Lisp, with .NET framework, giving developers a powerful development environment.

Working with F#
To work with the latest version of this functional programming language, one can either download and install the Visual Studio 2010 Beta 1 or use the CTP add-on for Visual Studio 2008. In this sample implementation we use Visual Studio 2008 with the F# add-on. To download and install this add-on visit 'msdn.microsoft.com/en-us/fsharp/default.aspx' and download 'InstallFSharp.msi' file.

Once this add-on has been installed, it will add a new project type, 'Visual F#' in the 'New Project' window. To start creating an F# application, open Visual Studio and create a new F# project by selecting 'F# Application' from template window ('ConsoleApplication1'). Here is a simple F# application that calculates squares for ten numbers:

#light
let square x = x * x
let numbers = <1 .. 10>
let s = List.map square numbers
printfn "Square of 10 numbers = %A"s
open System
Console.ReadKey(true)

In the above code '#light' is the complier directive while the second line of the code declares a function that calculates squares of numbers. The difference between this code and similar C# code shown below is that one does not need to specify 'type' information. F# compiler figures this out automatically. The third line of code lists the ten numbers to be squared. The fourth line maps square function to each number to be squared.

To run this code simply press 'F5' from the key board. This will result in a console window with squares of first ten numbers. To enhance efficiency while writing code, F# plug-in for C# also comes with 'F# Interactive Console' for compiling and executing code snippets. Simply highlight the code to be executed and press 'ALT+ENTER.' This will bring up the FSI window. After this, the highlighted code is directly sent to FSI and results are displayed. In the FSI window, type:

List.map square <12..24>;;

Now press 'ENTER.' The result will be displayed as:

val it : int list =
<144; 169; 196; 225; 256; 289; 324; 361; 400; 441; 484; 529; 576>

If you write the same application in C#, the number of code lines is considerably higher. Have a look:

using System;
using System.Text;

namespace ConsoleApplication1
{
class Program
{
static void Main(string<> args)
{
int Square;
Console.WriteLine ("\tNumber\tSquare");
for (int Number = 1; Number <= 10;Number++)

{
Square = Number * Number;
Console.WriteLine ("\t{0}\t{1}", Number, Square);
}

Console.ReadLine();
}
}
}

After having gone through the sample implementation given above, it must have become abundantly clear that the way code is to be written in F#, the latest functional programming language, included in the Visual Studio 2010 is simple and close to how one actually tries to find solutions to mathematical expressions related to day-to-day problems, thus making things a lot simpler for scientists and engineers.