Intro to Rust

Slides from my Rust talk at WeRise.tech

Transcript

1. Rust Dan Callahan @callahad Batgirl (2016–) #8
2. Batgirl (2016–) #8
4. ☑ Pop Culture ☐ Programming?
6. Ownership What Demos Mutability
7. Ownership What Demos Mutability
8. Ownership What Demos Mutability
9. Ownership What Demos Mutability
10. What is Rust?
11. C’s performance and portability, but with guaranteed safety.
12. C’s performance and portability, but with guaranteed safety.
13. “Systems programming
 without fear.”
14. Julia Evans @b0rk jvns.ca/blog/2016/09/11/rustconf-keynote
15. Julia Evans @b0rk jvns.ca/blog/2016/09/11/rustconf-keynote
16. “It’s not complicated”
17. Ownership
18. fn main() { { let x = vec![‘a’,‘b’,‘c’]; println!(“{}”, x[0]); } } Stack Heap Try it
19. fn main() { { let x = vec![‘a’,‘b’,‘c’]; println!(“{}”, x[0]); } } ➟ Stack Heap Try it
20. fn main() { { let x = vec![‘a’,‘b’,‘c’]; println!(“{}”, x[0]); } } ➟ Stack Heap a b c Try it
21. fn main() { { let x = vec![‘a’,‘b’,‘c’]; println!(“{}”, x[0]); } } ➟ Stack Heap x PTR LEN CAP a b c 3 3 Try it
22. fn main() { { let x = vec![‘a’,‘b’,‘c’]; println!(“{}”, x[0]); } } ➟ a Stack Heap x PTR LEN CAP a b c 3 3 Try it
23. fn main() { { let x = vec![‘a’,‘b’,‘c’]; println!(“{}”, x[0]); } } ➟ ? Stack Heap a b c Try it
24. fn main() { { let x = vec![‘a’,‘b’,‘c’]; println!(“{}”, x[0]); } } ➟ Stack Heap x PTR LEN CAP a b c 3 3 Owner Try it
25. fn main() { { let x = vec![‘a’,‘b’,‘c’]; println!(“{}”, x[0]); } } ➟ Stack Heap x PTR LEN CAP a b c 3 3 x Owner Try it
26. fn main() { { let x = vec![‘a’,‘b’,‘c’]; println!(“{}”, x[0]); } } Stack Heap x PTR LEN CAP a b c 3 3 x Owner ➟ a Try it
27. fn main() { { let x = vec![‘a’,‘b’,‘c’]; println!(“{}”, x[0]); } } Stack Heap Owner ➟ Try it
28. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = &x; println!(“{}”, x[0]); } println!(“{}”, y[0]); } Stack Heap Try it
29. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = &x; println!(“{}”, x[0]); } println!(“{}”, y[0]); } ➟ Stack Heap Try it
30. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = &x; println!(“{}”, x[0]); } println!(“{}”, y[0]); } ➟ Stack Heap &Vec<Char> Try it
31. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = &x; println!(“{}”, x[0]); } println!(“{}”, y[0]); } ➟ Stack Heap &Vec<Char> y Try it
32. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = &x; println!(“{}”, x[0]); } println!(“{}”, y[0]); } ➟ Stack Heap y x PTR LEN CAP a b c 3 3 x Owner Try it
33. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = &x; println!(“{}”, x[0]); } println!(“{}”, y[0]); } ➟ Stack Heap y x PTR LEN CAP a b c 3 3 x Owner Try it
34. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = &x; println!(“{}”, x[0]); } println!(“{}”, y[0]); } ➟ Stack Heap y x PTR LEN CAP a b c 3 3 x Owner a Try it
35. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = &x; println!(“{}”, x[0]); } println!(“{}”, y[0]); } ➟ Stack Heap y Owner Try it
36. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = &x; println!(“{}”, x[0]); } println!(“{}”, y[0]); } ➟ Stack Heap y Owner ? Try it
37. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = &x; println!(“{}”, x[0]); } println!(“{}”, y[0]); } ➟ Stack Heap y Owner Compiler
 X Try it
38. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = x; println!(“{}”, x[0]); } println!(“{}”, y[0]); } Stack Heap Owner Try it
39. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = x; println!(“{}”, x[0]); } println!(“{}”, y[0]); } ➟ Stack Heap Owner Try it
40. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = x; println!(“{}”, x[0]); } println!(“{}”, y[0]); } ➟ Stack Heap Vec<Char> Owner Try it
41. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = x; println!(“{}”, x[0]); } println!(“{}”, y[0]); } ➟ Stack Heap Vec<Char> y PTR LEN CAP Owner Try it
42. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = x; println!(“{}”, x[0]); } println!(“{}”, y[0]); } ➟ Stack Heap y PTR LEN CAP Owner a b c 3 3 x PTR LEN CAP x Try it
43. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = x; println!(“{}”, x[0]); } println!(“{}”, y[0]); } ➟ Stack Heap y PTR LEN CAP Owner a b c 3 3 x PTR LEN CAP x Try it
44. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = x; println!(“{}”, x[0]); } println!(“{}”, y[0]); } ➟ Stack Heap y PTR LEN CAP Owner a b c 3 3 x PTR LEN CAP 3 3 x Try it
45. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = x; println!(“{}”, x[0]); } println!(“{}”, y[0]); } ➟ Stack Heap y PTR LEN CAP Owner a b c 3 3 x PTR LEN CAP 3 3 x Try it
46. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = x; println!(“{}”, x[0]); } println!(“{}”, y[0]); } ➟ Stack Heap y PTR LEN CAP Owner a b c 3 3 x PTR LEN CAP 3 3 x y Try it
47. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = x; println!(“{}”, x[0]); } println!(“{}”, y[0]); } ➟ Stack Heap y PTR LEN CAP Owner a b c 3 3 x PTR LEN CAP 3 3 x y Try it
48. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = x; println!(“{}”, x[0]); } println!(“{}”, y[0]); } ➟ Stack Heap y PTR LEN CAP Owner a b c 3 3 x PTR LEN CAP 3 3 x y Compiler
 X Try it
49. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = x; // println!(“{}”, x[0]); } println!(“{}”, y[0]); } ➟ Stack Heap y PTR LEN CAP Owner a b c 3 3 y Try it
50. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = x; // println!(“{}”, x[0]); } println!(“{}”, y[0]); } ➟ Stack Heap y PTR LEN CAP Owner a b c 3 3 y a Try it
51. fn main() { let y; { let x = vec![‘a’,‘b’,‘c’]; y = x; // println!(“{}”, x[0]); } println!(“{}”, y[0]); } Stack Heap Owner Try it
52. One unique owner per allocation Memory freed when owner leaves scope
 All other references must also be out of scope Ownership can be passed
 Invalidates previous owner Ownership Rules
53. If it compiles, it won’t segfault If it compiles, there are no data races No runtime overhead Rules are enforced by the compiler
54. Ashley Williams @ag_dubs github.com/ashleygwilliams/rustfest-2017
55. Ashley Williams @ag_dubs github.com/ashleygwilliams/rustfest-2017
56. Ashley Williams @ag_dubs github.com/ashleygwilliams/rustfest-2017
57. Mutability
58. Try it fn main() { let x = 5; x += 1; println!("{}", x) }
59. Try it fn main() { let x = 5; x += 1; println!("{}", x) } error[E0384]: re-assignment of immutable variable `x`
60. Try it fn main() { let mut x = 5; x += 1; println!("{}", x) }
61. Try it fn main() { let mut x = 5; x += 1; println!("{}", x) } 6
62. Try it fn main() { let mut x = 5; add_one(&mut x); println!("{}", x) } fn add_one(num: &mut i32) { *num += 1; }
63. Try it fn main() { let mut x = 5; add_one(&mut x); println!("{}", x) } fn add_one(num: &mut i32) { *num += 1; } 6
64. Try it fn main() { let mut x = 5; let y = &mut x; add_one(y); println!("{}", x) } fn add_one(num: &mut i32) { *num += 1; }
65. Try it fn main() { let mut x = 5; let y = &mut x; add_one(y); println!("{}", x) } fn add_one(num: &mut i32) { *num += 1; } error[E0502]: cannot borrow `x` as immutable because it is also borrowed as mutable
66. Try it fn main() { let mut x = 5; { let y = &mut x; add_one(y); } println!("{}", x) } fn add_one(num: &mut i32) { *num += 1;
67. Try it fn main() { let mut x = 5; { let y = &mut x; add_one(y); } println!("{}", x) } fn add_one(num: &mut i32) { *num += 1; 6
68. All variables are immutable by default Only one mutable reference at a time
 But as many immutable &’s as you want Mutable references block all other access
 The &mut must go out of scope before using other &’s Mutability Rules
69. Demos
70. Python + Rust Interop
 github.com/callahad/python-rust-ffi Servo Parallel Browser Project
 servo.org WebAssembly
 (Soon: github.com/rust-lang/rust/issues/38805) Demos
72. Trailheads
73. doc.rust-lang.org/book Carol Nichols @carols10cents
74. rust-lang.org rustbyexample.com reddit.com/r/rust Dan Callahan @callahad