This document provides an introduction to the functional programming language F#. It begins with an introduction from the presenter and asks who in the audience has experience with various programming languages. The goals of the presentation are then outlined as giving background on functional programming ideas, covering basic F# syntax, and introducing functional programming and F# without the goal of converting the audience. Key functional programming concepts are then defined such as first class functions, higher-order functions, immutable data, and recursion. Functional principles of composition over inheritance and separating functions from data are discussed. Examples are provided for these principles. The document concludes by stating F# supports additional paradigms like object-oriented and imperative programming beyond just being functional first and asks what industries and companies

1. Introduction to
F#

2. What’s a Seth?
• SD Native
• Graduated a couple times
• Developer – Blend Interactive
• Consultant
• Founder – Sioux Falls Developers Group
• Cofounder – This thing we’re at today

3. Who are you?
• Java peoples?
• .Net people?
• Python/Ruby people?
• Why are you interested?

4. Goals
• Give a little background
• Explain some of the basic FP ideas
• Cover F# syntax basics
• Converting you to FP and F# is NOT my goal

5. Functional Programming
• First Class Functions
• Higher-Order Functions
• No Shared State
• No Side Effects
• Immutable data
• Recursion

6. Functional Principles
• Composition over Inheritance
• Separate functions from data
• Referential Transparency

7. Composition Over
Inheritance
• Write functions that transform known input to known
output
• Output of one function is input to the next
• Things like LINQ
o Repeater.DataSource = myList.Where(x=> x.Length >
5).OrderBy(x=>x.Name);

8. Separate Functions From
Data
• But why wouldn’t you want possibly re-usable
functionality tightly bound to a specific data type?

9. Together Separate
• x.Method() • Method(x)
• Our brains probably • But what if we want to
prefer this way, nothing use it on y?
wrong with that • Method(y)
• Since C# is taking on • darn
some FP concepts
extension methods
semi-allow for this

10. Referential Transparency
• ???
• When it comes to null references

11. F# isn’t just functional
• So I’m kind of wasting your time right?
• F# is multi-paradigm, but “functional first”
o Object Oriented – Smalltalk
o Functional – Lisp, Scala, Haskell, OCaml, etc.
o Imperative – C
• "I like to think of F# as a strongly typed python
for .net” – Don Syme, MS Research/Creator of F#

12. Object Oriented
Encapsulation
Inheritance
Polymorphism

13. Demo

14. What industries?
• Finance
• Front Office
• Banking
• Games
• 3D Graphics
• Telecoms
• Investment Banks
• Advertising

15. What companies?
• Optiver
• EDF
• Computational Problems
• Credit Suisse
• Data Analytics
• Measured Progress
• guardian.co.uk

16. Questions