Slides from Functional Programming Day in Oslo 17. December - Introduction to F#. Slides are in Norwegian.

1. FUNCTIONAL
PROGRAMMING IN F#
An introduction
Functional Programming Day
Jonas Follesø
17/12/2012

2. ABOUT ME
Jonas Follesø
Scientist & Manager BEKK
Trondheim
github.com/follesoe
twitter.com/follesoe
jonas.folesoe.no

3. AGENDA
Part 1 – F# & it’s history
Part 2 – F# Fundamentals
Part 3 – Units of Measure
Part 4 – Type Providers
Part 5 – Async Workflows
Part 6 – Summary & Resources

4. 2006:
IT2105 -
Functional
Programming

5. Scheme

7. Func<int, bool> isEven = n => n%2 == 0;
Action<int> print = n => Console.WriteLine("The number is {0}", n);
var numbers = new List<int> {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
numbers.Where(isEven)
.ToList()
.ForEach(print);
C#

8. Disclaimer:
F# beginner

9. Part 1
What is F#?

10. WHAT IS F#?
… a statically typed, functional first, hybrid, open source,
programming language for the CLR…

11. IN MICROSOFT OWN WORDS…
… a productive, supported, interoperable, functional
language that allows you to write simple code to solve
complex problems.

12. QUICK SHOW OF HANDS…
JVM? CLR?

13. IT HAS BEEN SAID…
…F# is to C# what Scala is to Java...

14. HISTORY
• Designed and implemented by Don Syme at
Microsoft Research
• Wanted a functional programming language
on the CLR for research and scientific
computing
Photo: John Lamb

15. F# LANGUAGE INFLUENCES
OCaml
F# C#/.NET
Similar core language Similar object model

16. HISTORY
Pre 2005 2005 2010 2012
F# 0.9 F# 1.0 F# 2.0 F# 3.0
Microsoft VS2005 VS2010 VS2012
Research Download Built-in Built-in
04. November 2010
F# compiler and libraries
released under Apache 2.0 license

20. Demo: F#
Fundamentals

21. Part 2:
Units of
Measure

22. MARS CLIMATE ORBITER

23. MARS CLIMATE ORBITER
The 'root cause' of the loss of the spacecraft was the failed
translation of English units into metric units in a segment of
ground-based, navigation-related mission software
http://mars.jpl.nasa.gov/msp98/news/mco991110.html

24. Demo:
Units of
Measure

25. Part 3
Type
Providers

26. THE CHALLENGE
1. The world is information rich
2. Our programming languages are information sparse

27. IMPEDANCE MISS MATCH
• Rich information spaces with structured data
Open APIs
Web
OData Databases and data
Services
markeds
XML Semantic
CRM data Others…
Documents Web

28. IMPEDANCE MISS MATCH
• Need bridging mechanisms to access structured data in our programs
• Hand-written static libraries
• Generated static libraries
• Dynamically-typed information representation

29. F# 3.0 TYPE PROVIDERS
A Type Provider is…
Statement
completion for data
A design-time component that provides a
computed space of types and methods
Extensible and
open
A compiler/IDE extension
Breaking down
walls!
The static counterpart to dynamic languages:
Compile-time meta programming

30. Demo:
Type
Providers

31. Part 5
Async
Workflows

32. Part 6
Summary &
Resources

33. Why?

34. POSSIBLE REASONS – MY OWN SPECULATIONS
C# is too Microsoft
good? positioning?

35. IS C# TOO GOOD?
• Implicitly Typed Local Variables
• Extension Methods
• Lambda Expressions and Higher Order Functions
• LINQ
• Task Parallel Library
• Extension Methods
• New asynchronous language constructs (async & await)

36. MICROSOFT POSITIONING
C#, VB,
F# 3.0 F# 2.0 HTML5, JS
Transformation,
Access
Analysis, Presentation,
Data,
Algorithms, Publication,
Information,
Code, Experience
Services
Parallel

37. Learning
Resources

38. HTTP://WWW.TRYFSHARP.ORG/

39. HTTP://FSHARPFORFUNANDPROFIT.COM/

40. FILE – NEW – F# TUTORIAL

41. BOOKS
Programming F# 3.0 Expert F# 3.0
by Chris Smith by Don Syme, Adam Granicz
and Antonio Cisternino

42. THANK YOU!
Jonas Follesø
http://jonas.follesoe.no
@follesoe