Function Programming, The 1st Aid Kit PureScript(ed)

Functional Programming, the First-Aid Kit
Purescript(ed)
This Kit proposes to discuss these 3 main points:
- What is FP exactly?
- The differences between FP and other programming paradigms
- Basics of FP (recursion, lazy evaluation, purity and types)
All this with flavoured in PureScript, functional language inspired by Haskell which compiles to Javascript

Link of the meetup containing my talk and another interesting talk given by @bloodyowl (on twitter) about ReasonML (In French): https://www.youtube.com/watch?v=hbcEYBQ4x70

Transcript

1. Functional Programming The 1st Aid Kit PureScript(ed)
2. In In a nutshell What is FP? How is FP different from the others? The Basics of FP Wrapping up In
3. Name: Yoan Ribeiro Title: Full-Time Learner Works at: JS-Republic @yoanribeiro Yoanribeiro
4. Let’s do this!
5. WTH is Functional Programming?
6. Functional Programming (def) Programming Paradigm that treats computation as the evaluation of mathematical functions and avoids changing-state and mutable data. By Wikipedia
8. For real now More like a style of programming; Expressions (statements); Recursion (iteration); Functions are King (or Queen). @yoanribeiro
9. FP Style - Expressions (statements) Don’t Do @yoanribeiro
10. FP Style - Recursion (iteration) Do Don’t @yoanribeiro
11. FP Style - Functions are King Functions are the building blocks of our programs; Functions are a mapping from input to output; Functions can be parameters and return other Functions. State does not (usually) enter in this equation. @yoanribeiro
12. FP Style - Functions are King @yoanribeiro
13. FP Style - Functions are King Functions can be parameters and return other Functions. @yoanribeiro
14. How is it different from the others?
15. Abstraction (def) denoting an idea, quality, or state rather than a concrete object. By Oxford Dictionary
16. Abstraction in OOP Objects are the end-goal when abstracting (shocker). We interact with them by using methods. Easy to represent and visualise. @yoanribeiro
17. Abstraction in FP Functions are the end-goal when abstracting (shocker again). From these functions the types come naturally. Focused, by default, on the relations between the different components. @yoanribeiro
18. (Back to) Basics of FP (Back to) Basics of FP
19. Quick word about PureScript PureScript is a functional programming language inspired by Haskell (with major differences); Compiles to readable JS; Active community. http://www.purescript.org/
20. Composition Main operation for gluing functions together. g >>> f or f <<< g @yoanribeiro
21. Lazy VS Eager O1 - Only calculates the value when needed (Hello Memoisation); O2 - Calculates the value as soon as it is bounded to a variable. @yoanribeiro
22. Strive for Purity Pure function = No side-effect + Immutable Data @yoanribeiro
23. Types Our functions have a input type and an output type. Types can also be glued e.g. Tuple, Either (Union) A x B A + B @yoanribeiro
24. Types in PureScript JS Primitive types: String, Boolean, Number Integer: Int is transformed into Number but operation are implemented differently. Array a : JS Array but all elem must have the same type Records : JS Objects, e.g type Person = { name :: String } Polymorphic types: forall a . List a @yoanribeiro
26. Ad summam FP is a style of programming; FP mindset is useful in any programming language; Functions are cool: composition, pure & etc.
27. Come to the Functional (Programming) Side FP encourages safe way of programming & quick prototyping FP tends to be more elegant than the others FP + Pattern matching = Heaven Immutable data => ¬ race-condition => Safe multithreading Easier to be parallelised Etc. @yoanribeiro