This document discusses F# and functional programming. F# is a multi-paradigm language from Microsoft that supports functional, object-oriented and imperative programming. It provides powerful and flexible syntax that allows for shorter, more elegant code and increased programmer productivity. Functional programming emphasizes declaring what computations should be done rather than how to do them, and it enables easy parallel and asynchronous programming for scalability. The document provides examples of code in F# compared to C# and outlines some benefits of functional languages.

1. and functional programming

2. Presentation Agenda
1. Motivation & history
2. Features of F# language
3. Abilities of functional programming
4. F# code examples
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3. What is F# About?
 New functional language from Microsoft
 Why is Microsoft investing in functional
programming?
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4. What is F# About?
 New functional language from Microsoft
 Why is Microsoft investing in functional
programming?
 Powerful language
 Simplicity
 Programmers productivity
 Scalability
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5. What is F# About?
 F# is multi‐paradigm .NET language
 Functional programming
 Object oriented programming
 Imperative programming
 .NET ‐> built on CLI
 Statically typed language
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6. About History
 Project since 2002 at Microsoft Research
 January 2008 – first CTP
 Full support in Visual Studio 2010
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7. Functional Programming
 SAYING “WHAT” RATHER THAN “HOW”
 “how” = imperative way
 “what” = declarative way (better readable)
 Immutability
 Parallel & async. programming (scalability)
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8. Functional Languages
 Expressible languages
 But why?
 Easy testing
 Scalability
 Processing large sets of data
 Effectiveness
 F#, C#, Haskel, Erlang, Scala, Lisp
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9. Code
//F# //C#
open System using System;
let a = 2
namespace ConsoleApplication1
Console.WriteLine a
{
class Program
{
static int a()
{
return 2;
}
static void Main(string[] args)
{
Console.WriteLine(a);
}
More Noise }
Than Signal! }
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10. F# Pleasure C# Pain
abstract class Command
type Command = Command of (Rover ‐> unit) {
public virtual void Execute();
}
let BreakCommand = abstract class MarsRoverCommand : Command
Command(fun rover ‐> rover.Accelerate(‐1.0)) {
protected MarsRover Rover { get; priv
let TurnLeftCommand =
Command(fun rover ‐> rover.Rotate(‐5.0<degs>)) public MarsRoverCommand(MarsRover rov
{
this.Rover = rover;
}
}
class BreakCommand : MarsRoverCommand
{
public BreakCommand(MarsRover rover)
: base(rover)
{
}
public override void Execute()
{
Rover.Rotate(‐5.0);
}
}
class TurnLeftCommand : MarsRoverCommand
{…
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11. Summary
 F# is multi‐paradigm language, mainly functional
 Powerful
 Flexible syntax
 Shorter & elegant code
 Increase productivity
 Parallel & async. programming = extremely easy
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12. Sources
http://www.fsharp.net
• Real World Functional Programming • Programming F# (Chris Smith)
(Tomas Petricek, John Skeet)
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13. Questions
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14. The End
Radek Míka
radek@radekmika.cz