Seth Larson's presentation to South Dakota Code Camp about F#.

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