Oden – A Functional Programming Language for the Go Ecosystem (Curry On 2016)

This talk will introduce Oden, an experimental, statically typed, functional programming language built for the Go ecosystem. We will look at how Oden aims to leverage the great features of Go — static linking, cross-compilation, goroutines, channels and the great set of libraries and tools — and enable higher-level abstractions, generics and a safer yet more flexible type system.

Transcript

1. Oden A Functional Programming Language for the Go Ecosystem Oskar Wickström @owickstrom
2. http://empear.com @owickstrom
3. Agenda • Background • Project Goals • Current State • What’s next? • Questions @owickstrom
4. Background @owickstrom
5. Things I’ve been thinking about lately @owickstrom
6. I want type-safe functional programming for writing web applications. @owickstrom
7. Haskell is a great language. @owickstrom
8. Can we have the safety of Haskell, but in a smaller and simpler language? @owickstrom
9. I want fast, "clean slate" compilation as an option. @owickstrom
10. We should optimize for writing code that is correct, understandable, and safe to change. @owickstrom
11. We should not optimize for cleverness. @owickstrom
12. Maybe static typing on top of Javascript? @owickstrom
13. Having to write FFI bindings to use libraries is cumbersome. Can the compiler do this for us? @owickstrom
14. Can we reuse all the good stuff from Go, but use a functional language? @owickstrom
15. Yes, we can! @owickstrom
16. Why Go? • Ecosystem of libraries and tools • Goroutines, channels • Cross-compilation • Static linking • Simple compile target • Fast compiler @owickstrom
17. What I’m missing in Go @owickstrom
18. Expressions over statements @owickstrom
19. Generic Programming @owickstrom
20. Abstraction @owickstrom
21. func (c *dropboxClient) GetFile(accessToken, dropboxSrc, localTarget string) error { url : "https://content.dropboxapi.com/ /files/auto" dropboxSrc req, err : http.NewRequest("GET", url, nil) req.Header.Add("Authorization", "Bearer " accessToken) if err ! nil { return err } client : &http.Client{} res, err : client.Do(req) if err ! nil { return err } if res.StatusCode { return ErrNotFound } if res.StatusCode || res.StatusCode { return errors.New("Dropbox request failed: " res.Status) } f, err : os.Create(localTarget) if err ! nil { return err } io.Copy(f, res.Body) if err ! nil { return err } return nil } @owickstrom
22. func (c *dropboxClient) GetFile(accessToken, dropboxSrc, localTarget string) error { url : "https://content.dropboxapi.com/ /files/auto" dropboxSrc req, err : http.NewRequest("GET", url, nil) req.Header.Add("Authorization", "Bearer " accessToken) if err ! nil { return err } client : &http.Client{} res, err : client.Do(req) if err ! nil { return err } if res.StatusCode { return ErrNotFound } if res.StatusCode || res.StatusCode { return errors.New("Dropbox request failed: " res.Status) } f, err : os.Create(localTarget) if err ! nil { return err } io.Copy(f, res.Body) if err ! nil { return err } return nil } @owickstrom
23. if err ! nil { return err } @owickstrom
24. ... f, err : os.Create(localTarget) if err ! nil { return err } io.Copy(f, res.Body) if err ! nil { return err } return nil } @owickstrom
25. Project Goals @owickstrom
26. Use Go as a platform @owickstrom
27. Avoid cleverness, prefer clarity @owickstrom
28. Expressions over statements @owickstrom
29. Support generic programming @owickstrom
30. Support good abstractions @owickstrom
31. Type inference @owickstrom
32. Immutability by default @owickstrom
33. Pattern matching @owickstrom
34. Exhaustiveness checking @owickstrom
35. Simple interoperability with Go @owickstrom
36. Fun! @owickstrom
37. Open-source from the beginning @owickstrom
38. Figure: MVP Pyramid @owickstrom
39. Current State @owickstrom
40. Hello World package main main() println("Hello World") @owickstrom
41. Operators !true - * / ( - ) / * -( ) ! "Foo" "Bar" false && (true || ( )) @owickstrom
42. Operator Desugaring Operator Protocol Method - Num Negate ! Logical Not Num Add - Num Subtract * Num Multiply / Num Divide && Logical Conjunction || Logical Disjunction Monoid Apply @owickstrom
43. No custom operators @owickstrom
44. No macros @owickstrom
45. Curried Functions plus(x, y) x y twice(f, x) f(f(x)) plusTwenty twice(plus( )) forty plusTwenty( ) @owickstrom
46. Curried Functions with Type Signatures plus : int - int - int plus(x, y) x y twice : forall a. (a - a) - a - a twice(f, x) f(f(x)) plusTwenty : int - int plusTwenty twice(plus( )) forty : int forty plusTwenty( ) @owickstrom
47. Imports from Go package main import html main() { println(html.EscapeString("Simon & Garfunkel")) // Simon & Garfunkel } @owickstrom
48. Imports from Go package main import foreign "html" main() { println(html.EscapeString("Simon & Garfunkel")) // Simon & Garfunkel } @owickstrom
49. Records sweden { official "Kingdom Of Sweden", population , capital "Stockholm" } usa { official "United States of America", population , capital "Washington D.C." } @owickstrom
50. Record Types sweden : { official : string, population : int, capital : string } @owickstrom
51. Records and Row Polymorphism fullName(person) person.firstName " " person.lastName @owickstrom
52. Records and Row Polymorphism fullName : forall r. { firstName : string, lastName : string | r } - string @owickstrom
53. Protocols Spoiler: Very similar to type classes @owickstrom
54. Protocols impl Monoid({ x: int, y: int }) { Apply(p , p ) { x p .x p .x, y p .y p .y } Identity { x , y } } @owickstrom
55. Protocols position { x , y } distance { x , y } target Monoid::Apply(position, distance) @owickstrom
56. Protocols position { x , y } distance { x , y } target position distance @owickstrom
57. Procotols are not simple @owickstrom
58. That’s not all @owickstrom
59. Finding more information @owickstrom
60. oden-lang.org @owickstrom
61. oden-lang.org/user-guide/latest/ @owickstrom
62. playground.oden-lang.org @owickstrom
63. @odenlang @owickstrom
64. What’s next? @owickstrom
65. Thank you! @owickstrom