What is Rust?

You may have seen Rust on Hacker News, Reddit or Twitter, but what is all the hype about? With Rust just recently having become stable, now’s a great time to learn more about this emerging language that is taking on old stalwarts like C++ without giving up on the expressiveness of higher level languages.

In this talk, Yehuda will talk about Rust’s ownership system, which provides automatic memory management without paying the runtime cost of a garbage collector or reference counting. Instead, Rust guarantees, at compile time, that your program will never segfault. Learn how that can work, and how the same approach makes your Rust code remarkably resilient against memory leaks.

Whether you’re a grizzled systems programmer or a dynamic language programmer looking to dip your toe in, this talk will have something for you.

Transcript

2. Node.js
3. Expressiveness Speed JS
4. Underestimated: Ubiquity
5. Client Side Server Side JS JS
6. Expressiveness Speed JS
7. Expressiveness Speed JS V8
8. Expressiveness Speed JS V8 ES6+
9. Enabling Technologies
10. Me, A Systems Programmer?
11. Me, A Systems Programmer? That's someone else's job…
12. Me, A Systems Programmer?
13. Me, A Systems Programmer? "Systems programming" sounds hard… and dangerous
14. Me, A Systems Programmer?
15. Me, A Systems Programmer? What is "Systems programming" anyway?
16. What is Systems Programming? • Programming without a GC • Programming directly against the metal, without abstraction costs • Pay-as-you-go, lightweight runtime, or no runtime • Zero-cost abstractions • When "it doesn't end up mattering" isn't true
17. That Doesn't Need to Mean • malloc and free • Assembly Language • Targeting Unix-only or Windows-only • Old-school tools like hand-crafted Makefiles • Fighting with the linker • Writing your entire application in a systems language
19. Embedding, Performance, Low Memory
21. Fast, Safe, Parallel
22. How Does it Work?
24. Garbage Collection class  Point
    def  initialize(x,  y)
        @x,  @y  =  x,  y
    end
 end
 
 class  Line
    def  initialize(p1,  p2)
        @p1,  @p2  =  p1,  p2
    end
 
    def  length
        #  compute  length
    end
 end
 def  length(x1,  y1,  x2,  y2)
    p1  =  Point.new(x1,  y1)
    p2  =  Point.new(x2,  y2)
    line  =  Line.new(p1,  p2)
    line.length
 end
25. Garbage Collection def  length(x1,  y1,  x2,  y2)
    p1  =  Point.new(x1,  y1)
    p2  =  Point.new(x2,  y2)
    line  =  Line.new(p1,  p2)
    line.length
 end
26. Garbage Collection def  length(x1,  y1,  x2,  y2)
    p1  =  Point.new(x1,  y1)
    p2  =  Point.new(x2,  y2)
    line  =  Line.new(p1,  p2)
    line.length
 end
27. Garbage Collection def  length(x1,  y1,  x2,  y2)
    p1  =  Point.new(x1,  y1)
    p2  =  Point.new(x2,  y2)
    line  =  Line.new(p1,  p2)
    line.length
 end Point.new(x1,  y1)
28. Garbage Collection def  length(x1,  y1,  x2,  y2)
    p1  =  Point.new(x1,  y1)
    p2  =  Point.new(x2,  y2)
    line  =  Line.new(p1,  p2)
    line.length
 end Point.new(x1,  y1)
29. Garbage Collection def  length(x1,  y1,  x2,  y2)
    p1  =  Point.new(x1,  y1)
    p2  =  Point.new(x2,  y2)
    line  =  Line.new(p1,  p2)
    line.length
 end Point.new(x1,  y1) Point.new(x2,  y2)
30. Garbage Collection def  length(x1,  y1,  x2,  y2)
    p1  =  Point.new(x1,  y1)
    p2  =  Point.new(x2,  y2)
    line  =  Line.new(p1,  p2)
    line.length
 end Point.new(x1,  y1) Point.new(x2,  y2)
31. Garbage Collection def  length(x1,  y1,  x2,  y2)
    p1  =  Point.new(x1,  y1)
    p2  =  Point.new(x2,  y2)
    line  =  Line.new(p1,  p2)
    line.length
 end Point.new(x1,  y1) Point.new(x2,  y2) Line.new(p1,  p2)
32. Garbage Collection def  length(x1,  y1,  x2,  y2)
    p1  =  Point.new(x1,  y1)
    p2  =  Point.new(x2,  y2)
    line  =  Line.new(p1,  p2)
    line.length
 end Point.new(x1,  y1) Point.new(x2,  y2) Line.new(p1,  p2)
33. Garbage Collection def  length(x1,  y1,  x2,  y2)
    p1  =  Point.new(x1,  y1)
    p2  =  Point.new(x2,  y2)
    line  =  Line.new(p1,  p2)
    line.length
 end Point.new(x1,  y1) Point.new(x2,  y2) Line.new(p1,  p2) later… stop the world…
34. Garbage Collection def  length(x1,  y1,  x2,  y2)
    p1  =  Point.new(x1,  y1)
    p2  =  Point.new(x2,  y2)
    line  =  Line.new(p1,  p2)
    line.length
 end
35. Ownership
43. Ownership is the Right to Destroy
44. Right to Destroy pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  main()  {      let  book  =  read("book1.txt");      println!("Title:  {}",  book.title);   }
45. Right to Destroy pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  main()  {      let  book  =  read("book1.txt");      println!("Title:  {}",  book.title);   }
46. Right to Destroy pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  main()  {      let  book  =  read("book1.txt");      println!("Title:  {}",  book.title);   }
47. Right to Destroy pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  main()  {      let  book  =  read("book1.txt");      println!("Title:  {}",  book.title);   }
48. Right to Destroy pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  main()  {      let  book  =  read("book1.txt");      println!("Title:  {}",  book.title);   }
49. Right to Destroy pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  main()  {      let  book  =  read("book1.txt");      println!("Title:  {}",  book.title);   } note the lack of manual memory management
50. Transferring Ownership pub  struct  Book  {      title:  String,      chapters:  Vec<String>   }   fn  main()  {      let  book  =  read("book1.txt");      print_book(book);   }   fn  print_book(book:  Book)  {      println!("Title:  {}",  book.title);   }
51. Transferring Ownership pub  struct  Book  {      title:  String,      chapters:  Vec<String>   }   fn  main()  {      let  book  =  read("book1.txt");      print_book(book);   }   fn  print_book(book:  Book)  {      println!("Title:  {}",  book.title);   }
52. Transferring Ownership pub  struct  Book  {      title:  String,      chapters:  Vec<String>   }   fn  main()  {      let  book  =  read("book1.txt");      print_book(book);   }   fn  print_book(book:  Book)  {      println!("Title:  {}",  book.title);   }
53. Transferring Ownership pub  struct  Book  {      title:  String,      chapters:  Vec<String>   }   fn  main()  {      let  book  =  read("book1.txt");      print_book(book);   }   fn  print_book(book:  Book)  {      println!("Title:  {}",  book.title);   }
54. Transferring Ownership pub  struct  Book  {      title:  String,      chapters:  Vec<String>   }   fn  main()  {      let  book  =  read("book1.txt");      print_book(book);   }   fn  print_book(book:  Book)  {      println!("Title:  {}",  book.title);   }
55. Transferring Ownership pub  struct  Book  {      title:  String,      chapters:  Vec<String>   }   fn  main()  {      let  book  =  read("book1.txt");      print_book(book);   }   fn  print_book(book:  Book)  {      println!("Title:  {}",  book.title);   }
56. Transferring Ownership pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  main()  {      let  book  =  read("book1.txt");      print_book(book);      println!("Chapters:  {}",  book.chapters.len());   }   fn  print_book(book:  Book)  {      println!("Title:  {}",  book.title);   }
57. Transferring Ownership pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  main()  {      let  book  =  read("book1.txt");      print_book(book);      println!("Chapters:  {}",  book.chapters.len());   }   fn  print_book(book:  Book)  {      println!("Title:  {}",  book.title);   }
58. Transferring Ownership pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  main()  {      let  book  =  read("book1.txt");      print_book(book);      println!("Chapters:  {}",  book.chapters.len());   }   fn  print_book(book:  Book)  {      println!("Title:  {}",  book.title);   }
59. Transferring Ownership pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  main()  {      let  book  =  read("book1.txt");      print_book(book);      println!("Chapters:  {}",  book.chapters.len());   }   fn  print_book(book:  Book)  {      println!("Title:  {}",  book.title);   }
60. Transferring Ownership pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  main()  {      let  book  =  read("book1.txt");      print_book(book);      println!("Chapters:  {}",  book.chapters.len());   }   fn  print_book(book:  Book)  {      println!("Title:  {}",  book.title);   }
61. Transferring Ownership pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  main()  {      let  book  =  read("book1.txt");      print_book(book);      println!("Chapters:  {}",  book.chapters.len());   }   fn  print_book(book:  Book)  {      println!("Title:  {}",  book.title);   }
62. Transferring Ownership pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  main()  {      let  book  =  read("book1.txt");      print_book(book);      println!("Chapters:  {}",  book.chapters.len());   }   fn  print_book(book:  Book)  {      println!("Title:  {}",  book.title);   }
63. Transferring Ownership pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  main()  {      let  book  =  read("book1.txt");      print_book(book);      println!("Chapters:  {}",  book.chapters.len());   }   fn  print_book(book:  Book)  {      println!("Title:  {}",  book.title);   } error: use of moved value: `book.chapters` note: `book` moved here
64. Borrowing v. To receive something with the promise of returning it
65. Return this by 5pm on Friday
66. Return this by 5pm on Friday
67. Return this by 5pm on Friday
68. Return this by 5pm on Friday
69. Borrowing pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  main()  {      let  book  =  read("book1.txt");      print_book(&book);      println!("Chapters:  {}",  book.chapters.len());   }   fn  print_book(book:  &Book)  {      println!("Title:  {}",  book.title);   }
70. Borrowing pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  main()  {      let  book  =  read("book1.txt");      print_book(&book);      println!("Chapters:  {}",  book.chapters.len());   }   fn  print_book(book:  &Book)  {      println!("Title:  {}",  book.title);   }
71. Borrowing pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  main()  {      let  book  =  read("book1.txt");      print_book(&book);      println!("Chapters:  {}",  book.chapters.len());   }   fn  print_book(book:  &Book)  {      println!("Title:  {}",  book.title);   }
72. Borrowing pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  main()  {      let  book  =  read("book1.txt");      print_book(&book);      println!("Chapters:  {}",  book.chapters.len());   }   fn  print_book(book:  &Book)  {      println!("Title:  {}",  book.title);   }
73. Borrowing pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  main()  {      let  book  =  read("book1.txt");      print_book(&book);      println!("Chapters:  {}",  book.chapters.len());   }   fn  print_book(book:  &Book)  {      println!("Title:  {}",  book.title);   }
74. Borrowing pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  main()  {      let  book  =  read("book1.txt");      print_book(&book);      println!("Chapters:  {}",  book.chapters.len());   }   fn  print_book(book:  &Book)  {      println!("Title:  {}",  book.title);   }
75. Borrowing pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  main()  {      let  book  =  read("book1.txt");      print_book(&book);      println!("Chapters:  {}",  book.chapters.len());   }   fn  print_book(book:  &Book)  {      println!("Title:  {}",  book.title);   }
76. Borrowing pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  main()  {      let  book  =  read("book1.txt");      print_book(&book);      println!("Chapters:  {}",  book.chapters.len());   }   fn  print_book(book:  &Book)  {      println!("Title:  {}",  book.title);   }
77. Sub-Leasing
80. Return this by 5pm on Friday
81. Return this by 5pm on Friday
82. Return this by 4:30pm on Friday
86. Sub-Leasing fn  main()  {      let  book  =  read_book("book1.txt");      print_book(&book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  print_book(book:  &Book)  {      print_title(&book);      print_chapters(&book);   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   }
87. Sub-Leasing fn  main()  {      let  book  =  read_book("book1.txt");      print_book(&book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  print_book(book:  &Book)  {      print_title(&book);      print_chapters(&book);   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   }
88. Sub-Leasing fn  main()  {      let  book  =  read_book("book1.txt");      print_book(&book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  print_book(book:  &Book)  {      print_title(&book);      print_chapters(&book);   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   }
89. Sub-Leasing fn  main()  {      let  book  =  read_book("book1.txt");      print_book(&book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  print_book(book:  &Book)  {      print_title(&book);      print_chapters(&book);   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   }
90. Sub-Leasing fn  main()  {      let  book  =  read_book("book1.txt");      print_book(&book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  print_book(book:  &Book)  {      print_title(&book);      print_chapters(&book);   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   }
91. Sub-Leasing fn  main()  {      let  book  =  read_book("book1.txt");      print_book(&book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  print_book(book:  &Book)  {      print_title(&book);      print_chapters(&book);   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   }
92. Sub-Leasing fn  main()  {      let  book  =  read_book("book1.txt");      print_book(&book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  print_book(book:  &Book)  {      print_title(&book);      print_chapters(&book);   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   }
93. Sub-Leasing fn  main()  {      let  book  =  read_book("book1.txt");      print_book(&book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  print_book(book:  &Book)  {      print_title(&book);      print_chapters(&book);   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   }
94. Sub-Leasing fn  main()  {      let  book  =  read_book("book1.txt");      print_book(&book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  print_book(book:  &Book)  {      print_title(&book);      print_chapters(&book);   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   }
95. Sub-Leasing fn  main()  {      let  book  =  read_book("book1.txt");      print_book(&book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  print_book(book:  &Book)  {      print_title(&book);      print_chapters(&book);   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   }
96. Sub-Leasing fn  main()  {      let  book  =  read_book("book1.txt");      print_book(&book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  print_book(book:  &Book)  {      print_title(&book);      print_chapters(&book);   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   }
97. Sub-Leasing fn  main()  {      let  book  =  read_book("book1.txt");      print_book(&book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  print_book(book:  &Book)  {      print_title(&book);      print_chapters(&book);   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   }
98. Sub-Leasing fn  main()  {      let  book  =  read_book("book1.txt");      print_book(&book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  print_book(book:  &Book)  {      print_title(&book);      print_chapters(&book);   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   }
99. Sub-Leasing fn  main()  {      let  book  =  read_book("book1.txt");      print_book(&book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>
 }   fn  print_book(book:  &Book)  {      print_title(&book);      print_chapters(&book);   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   }
100. ✏️
101. Return this by 5pm on Friday and feel free to change it ✏️
102. Return this by 4:30pm on Friday but don't change it ✏️
103. ✏️
104. ✏️
106. fn  main()  {      let  mut  book  =  read_book("book1.txt");      print_book(&mut  book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>,      bookmark:  u32
 }   fn  print_book(book:  &mut  Book)  {      print_title(&book);      print_chapters(&book);      book.bookmark  =  100;   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   } Sub-Leasing
107. fn  main()  {      let  mut  book  =  read_book("book1.txt");      print_book(&mut  book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>,      bookmark:  u32
 }   fn  print_book(book:  &mut  Book)  {      print_title(&book);      print_chapters(&book);      book.bookmark  =  100;   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   } Sub-Leasing
108. fn  main()  {      let  mut  book  =  read_book("book1.txt");      print_book(&mut  book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>,      bookmark:  u32
 }   fn  print_book(book:  &mut  Book)  {      print_title(&book);      print_chapters(&book);      book.bookmark  =  100;   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   } Sub-Leasing
109. fn  main()  {      let  mut  book  =  read_book("book1.txt");      print_book(&mut  book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>,      bookmark:  u32
 }   fn  print_book(book:  &mut  Book)  {      print_title(&book);      print_chapters(&book);      book.bookmark  =  100;   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   } Sub-Leasing
110. fn  main()  {      let  mut  book  =  read_book("book1.txt");      print_book(&mut  book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>,      bookmark:  u32
 }   fn  print_book(book:  &mut  Book)  {      print_title(&book);      print_chapters(&book);      book.bookmark  =  100;   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   } Sub-Leasing
111. fn  main()  {      let  mut  book  =  read_book("book1.txt");      print_book(&mut  book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>,      bookmark:  u32
 }   fn  print_book(book:  &mut  Book)  {      print_title(&book);      print_chapters(&book);      book.bookmark  =  100;   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   } Sub-Leasing
112. fn  main()  {      let  mut  book  =  read_book("book1.txt");      print_book(&mut  book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>,      bookmark:  u32
 }   fn  print_book(book:  &mut  Book)  {      print_title(&book);      print_chapters(&book);      book.bookmark  =  100;   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   } Sub-Leasing
113. fn  main()  {      let  mut  book  =  read_book("book1.txt");      print_book(&mut  book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>,      bookmark:  u32
 }   fn  print_book(book:  &mut  Book)  {      print_title(&book);      print_chapters(&book);      book.bookmark  =  100;   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   } Sub-Leasing
114. fn  main()  {      let  mut  book  =  read_book("book1.txt");      print_book(&mut  book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>,      bookmark:  u32
 }   fn  print_book(book:  &mut  Book)  {      print_title(&book);      print_chapters(&book);      book.bookmark  =  100;   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   } Sub-Leasing
115. fn  main()  {      let  mut  book  =  read_book("book1.txt");      print_book(&mut  book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>,      bookmark:  u32
 }   fn  print_book(book:  &mut  Book)  {      print_title(&book);      print_chapters(&book);      book.bookmark  =  100;   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   } Sub-Leasing
116. fn  main()  {      let  mut  book  =  read_book("book1.txt");      print_book(&mut  book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>,      bookmark:  u32
 }   fn  print_book(book:  &mut  Book)  {      print_title(&book);      print_chapters(&book);      book.bookmark  =  100;   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   } Sub-Leasing
117. fn  main()  {      let  mut  book  =  read_book("book1.txt");      print_book(&mut  book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>,      bookmark:  u32
 }   fn  print_book(book:  &mut  Book)  {      print_title(&book);      print_chapters(&book);      book.bookmark  =  100;   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   } Sub-Leasing
118. fn  main()  {      let  mut  book  =  read_book("book1.txt");      print_book(&mut  book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>,      bookmark:  u32
 }   fn  print_book(book:  &mut  Book)  {      print_title(&book);      print_chapters(&book);      book.bookmark  =  100;   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   } Sub-Leasing
119. fn  main()  {      let  mut  book  =  read_book("book1.txt");      print_book(&mut  book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>,      bookmark:  u32
 }   fn  print_book(book:  &mut  Book)  {      print_title(&book);      print_chapters(&book);      book.bookmark  =  100;   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   } Sub-Leasing
120. fn  main()  {      let  mut  book  =  read_book("book1.txt");      print_book(&mut  book);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>,      bookmark:  u32
 }   fn  print_book(book:  &mut  Book)  {      print_title(&book);      print_chapters(&book);      book.bookmark  =  100;   }   fn  print_title(book:  &Book)  {      println!("Title:  {}",  book.title);   }   fn  print_chapters(book:  &Book)  {      let  len  =  book.chapters.len();      println!("Chapters:  {}",  len);   } Sub-Leasing
121. Rules of Borrowing • You can have many outstanding read-only borrows at once • A mutable borrow is unique: no other borrows, mutable
 or read-only, can occur at the same time
122. Rules of Borrowing • You can have many outstanding read-only borrows at once • A mutable borrow is unique: no other borrows, mutable
 or read-only, can occur at the same time • These rules are enforced by the compiler, not at runtime
123. Read-Only Borrows fn  main()  {      let  book1  =  read_book("book1.txt");      let  book2  =  read_book("book2.txt");      same(&book1,  &book2);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>   }   fn  same(a:  &Book,  b:  &Book)  -­‐>  bool  {      a.title  ==  b.title  &&      a.chapters  ==  b.chapters   }
124. Read-Only Borrows fn  main()  {      let  book1  =  read_book("book1.txt");      let  book2  =  read_book("book2.txt");      same(&book1,  &book2);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>   }   fn  same(a:  &Book,  b:  &Book)  -­‐>  bool  {      a.title  ==  b.title  &&      a.chapters  ==  b.chapters   } ✅
125. Two Read-Only Borrows fn  main()  {      let  book1  =  read_book("book1.txt");      same(&book1,  &book1);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>   }   fn  same(a:  &Book,  b:  &Book)  -­‐>  bool  {      a.title  ==  b.title  &&      a.chapters  ==  b.chapters   }
126. Two Read-Only Borrows fn  main()  {      let  book1  =  read_book("book1.txt");      same(&book1,  &book1);   }   pub  struct  Book  {
    title:  String,      chapters:  Vec<String>   }   fn  same(a:  &Book,  b:  &Book)  -­‐>  bool  {      a.title  ==  b.title  &&      a.chapters  ==  b.chapters   } ✅
127. Mutable Borrows Must Be Unique pub  struct  Book  {      title:  String,      chapters:  Vec<String>   }   fn  main()  {      let  book1  =  read_book("book1.txt");      let  mut  book2  =  read_book("book2.txt");      copy(&book1,  &mut  book2);   }   fn  copy(a:  &Book,  b:  &mut  Book)  {      b.title  =  a.title;   }
128. Mutable Borrows Must Be Unique pub  struct  Book  {      title:  String,      chapters:  Vec<String>   }   fn  main()  {      let  book1  =  read_book("book1.txt");      let  mut  book2  =  read_book("book2.txt");      copy(&book1,  &mut  book2);   }   fn  copy(a:  &Book,  b:  &mut  Book)  {      b.title  =  a.title;   } ✅
129. pub  struct  Book  {      title:  String,      chapters:  Vec<String>   }   fn  main()  {      let  mut  book  =  read_book("book1.txt");      copy(&book,  &mut  book);   }   fn  copy(a:  &Book,  b:  &mut  Book)  {      b.title  =  a.title;   } Mutable Borrows Must Be Unique
130. pub  struct  Book  {      title:  String,      chapters:  Vec<String>   }   fn  main()  {      let  mut  book  =  read_book("book1.txt");      copy(&book,  &mut  book);   }   fn  copy(a:  &Book,  b:  &mut  Book)  {      b.title  =  a.title;   } Mutable Borrows Must Be Unique
131. pub  struct  Book  {      title:  String,      chapters:  Vec<String>   }   fn  main()  {      let  mut  book  =  read_book("book1.txt");      copy(&book,  &mut  book);   }   fn  copy(a:  &Book,  b:  &mut  Book)  {      b.title  =  a.title;   } Mutable Borrows Must Be Unique ^~~~ error: cannot borrow `book` as mutable because it is also borrowed as immutable
132. Mutable Borrows Must Be Unique pub  struct  Book  {      title:  String,      chapters:  Vec<String>   }   fn  main()  {      let  mut  book  =  read_book("book1.txt");      copy(&book,  &mut  book);   }   fn  copy(a:  &Book,  b:  &mut  Book)  {      b.title  =  a.title;   }
133. Mutable Borrows Must Be Unique pub  struct  Book  {      title:  String,      chapters:  Vec<String>   }   fn  main()  {      let  mut  book  =  read_book("book1.txt");      copy(&book,  &mut  book);   }   fn  copy(a:  &Book,  b:  &mut  Book)  {      b.title  =  a.title;   } ^~~~ note: previous borrow of `book` occurs here
134. Mutable Borrows Must Be Unique pub  struct  Book  {      title:  String,      chapters:  Vec<String>   }   fn  main()  {      let  mut  book  =  read_book("book1.txt");      copy(&book,  &mut  book);   }   fn  copy(a:  &Book,  b:  &mut  Book)  {      b.title  =  a.title;   }
135. Mutable Borrows Must Be Unique pub  struct  Book  {      title:  String,      chapters:  Vec<String>   }   fn  main()  {      let  mut  book  =  read_book("book1.txt");      copy(&book,  &mut  book);   }   fn  copy(a:  &Book,  b:  &mut  Book)  {      b.title  =  a.title;   } ^ note: previous borrow ends here
136. Borrowing is the Secret Sauce
137. Closures
138. Closures fn  main()  {      println!("{:?}",  threes_squared(10));   }   fn  threes_squared(upto:  u32)  -­‐>  Vec<u32>  {      (0..upto)          .filter(|i|  i  %  3  ==  0)          .map(|i|  i.pow(2))          .collect()   }
139. Closed Over Variables fn  main()  {      println!("{:?}",  threes_squared(10,  "LOG"));   }   fn  threes_squared(upto:  u32,  string:  &str)  -­‐>  Vec<String>  {      (0..upto)          .filter(|i|  i  %  3  ==  0)          .map(|i|  format!("{}:  {}",  string,  i.pow(2)))          .collect()   }
140. Equivalent Performance fn  main()  {      println!("{:?}",  threes_squared(10,  "LOG"));   }   fn  threes_squared(upto:  u32,  string:  &str)  -­‐>  Vec<String>  {
    let  v  =  vec![];      loop  {
        if  i  %  3  ==  0  {              v.push(format!("{}:  {}",  string,  i  *  i));          }          if  i  <  upto  {  break;  }
    }      v   }
141. Details Abstracted fn  main()  {      println!("{:?}",  threes_squared(10,  "LOG"));   }   fn  threes_squared(upto:  u32,  string:  &str)  -­‐>  Vec<String>  {
    let  v  =  Vec::with_capacity(upto  -­‐  1);      loop  {
        if  i  %  3  ==  0  {              v.push(format!("{}:  {}",  string,  i  *  i));          }          if  i  <  upto  {  break;  }
    }      v   }
142. Details Abstracted fn  main()  {      println!("{:?}",  threes_squared(10,  "LOG"));   }   fn  threes_squared(upto:  u32,  string:  &str)  -­‐>  Vec<String>  {
    let  v  =  Vec::with_capacity(upto  -­‐  1);      loop  {
        if  i  %  3  ==  0  {              v.push(format!("{}:  {}",  string,  i  *  i));          }          if  i  <  upto  {  break;  }
    }      v   } Bounds Checks
143. Same Ownership Rules
144. FnOnce A closure that only runs once and can take ownership from its environment Fn A closure that cannot mutate its environment and can be shared across threads FnMut A closure that can mutate its environment but cannot be shared across threads
145. FnOnce fn  main()  {      let  buf  =  String::new();      stdin().read_line(&mut  buf).map(|size|  {
        println!("Read  {}  bytes",  size);          transfer(buf);
    });   }   fn  transfer(string:  String)  {      println!("Got  transferred  {:?}",  string);
 }
146. Unified Calling Syntax
147. Concurrency
148. "Shared Mutable State is the Root of All Evil"
150. Channels Forbid Aliasing
151. Channels Forbid Aliasing Functional Forbid Mutation
152. Channels Forbid Aliasing Functional Forbid Mutation Rust Forbid Both at the Same Time
153. Rules of Borrowing • You can have many outstanding read-only borrows at once • A mutable borrow is unique: no other borrows, mutable
 or read-only, can occur at the same time
154. Rules of Borrowing • You can have many outstanding read-only borrows at once • A mutable borrow is unique: no other borrows, mutable
 or read-only, can occur at the same time • You can alias or mutate, but not both at the same time
155. Send Safe to transfer across threads (no borrowed values) Sync Safe to share across threads (no racy "interior mutability")
156. spawn() fn  main()  {      let  book  =  read_book("book1.txt");      spawn(||  {          println!("{}",  book);      });   }
157. spawn() fn  main()  {      let  book  =  read_book("book1.txt");      spawn(||  {          println!("{}",  book);      });   }
158. spawn() fn  main()  {      let  book  =  read_book("book1.txt");      spawn(||  {          println!("{}",  book);      });   } ^~~~ error: `book` does not live long enough
159. spawn() fn  main()  {      let  book  =  read_book("book1.txt");      spawn(move  ||  {          println!("{}",  book);      });   }
160. scoped() fn  main()  {      let  book  =  read_book("book1.txt");      let  guard  =  scoped(||  {          println!("{}",  book);      });
 
    //  do  other  work
 
    let  output  =  guard.join();   }
161. scoped() fn  main()  {      let  book  =  read_book("book1.txt");      let  guard  =  scoped(||  {          println!("{}",  book);      });
 
    //  do  other  work
 
    let  output  =  guard.join();  //  default  impl  of  Drop   }
162. High Level Productivity
163. OO
164. OO Syntax struct  Circle  {      x:  f64,      y:  f64,      radius:  f64,   }   impl  Circle  {      fn  area(&self)  -­‐>  f64  {          std::f64::consts::PI  *  (self.radius  *  self.radius)      }   }
165. Traits
166. Iterators
167. Enums with Methods
168. Operators
169. Thank You!
170. Questions? @wycats