mirror of
https://github.com/adambard/learnxinyminutes-docs.git
synced 2024-12-23 17:41:41 +00:00
[rust/en] Update the Rust tutorial
This adjusts the English Rust tutorial for changes to the language and generally tweaks a few other things. Fixes #860.
This commit is contained in:
P1start
parent
dff86ae3cb
commit
ecc5d89841
@ -7,9 +7,13 @@ filename: learnrust.rs
|
||||
|
||||
Rust is an in-development programming language developed by Mozilla Research.
|
||||
It is relatively unique among systems languages in that it can assert memory
|
||||
safety *at compile time*. Rust’s first alpha release occurred in January
|
||||
2012, and development moves so quickly that at the moment the use of stable
|
||||
releases is discouraged, and instead one should use nightly builds.
|
||||
safety *at compile time* without resorting to garbage collection. Rust’s first
|
||||
release, 0.1, occurred in January 2012, and development moves so quickly that at
|
||||
the moment the use of stable releases is discouraged, and instead one should use
|
||||
nightly builds. On January 9 2015, Rust 1.0 Alpha was released, and the rate of
|
||||
changes to the Rust compiler that break existing code has dropped significantly
|
||||
since. However, a complete guarantee of backward compatibility will not exist
|
||||
until the final 1.0 release.
|
||||
|
||||
Although Rust is a relatively low-level language, Rust has some functional
|
||||
concepts that are generally found in higher-level languages. This makes
|
||||
@ -24,7 +28,8 @@ Rust not only fast, but also easy and efficient to code in.
|
||||
///////////////
|
||||
|
||||
// Functions
|
||||
fn add2(x: int, y: int) -> int {
|
||||
// `i32` is the type for 32-bit signed integers
|
||||
fn add2(x: i32, y: i32) -> i32 {
|
||||
// Implicit return (no semicolon)
|
||||
x + y
|
||||
}
|
||||
@ -34,71 +39,90 @@ fn main() {
|
||||
// Numbers //
|
||||
|
||||
// Immutable bindings
|
||||
let x: int = 1;
|
||||
let x: i32 = 1;
|
||||
|
||||
// Integer/float suffixes
|
||||
let y: int = 13i;
|
||||
let y: i32 = 13i32;
|
||||
let f: f64 = 1.3f64;
|
||||
|
||||
// Type inference
|
||||
let implicit_x = 1i;
|
||||
let implicit_f = 1.3f64;
|
||||
// Most of the time, the Rust compiler can infer what type a variable is, so
|
||||
// you don’t have to write an explicit type annotation.
|
||||
// Throughout this tutorial, types are explicitly annotated in many places,
|
||||
// but only for demonstrative purposes. Type inference can handle this for
|
||||
// you most of the time.
|
||||
let implicit_x = 1;
|
||||
let implicit_f = 1.3;
|
||||
|
||||
// Maths
|
||||
let sum = x + y + 13i;
|
||||
// Arithmetic
|
||||
let sum = x + y + 13;
|
||||
|
||||
// Mutable variable
|
||||
let mut mutable = 1;
|
||||
mutable = 4;
|
||||
mutable += 2;
|
||||
|
||||
// Strings //
|
||||
|
||||
|
||||
// String literals
|
||||
let x: &'static str = "hello world!";
|
||||
let x: &str = "hello world!";
|
||||
|
||||
// Printing
|
||||
println!("{} {}", f, x); // 1.3 hello world
|
||||
|
||||
// A `String` - a heap-allocated string
|
||||
// A `String` – a heap-allocated string
|
||||
let s: String = "hello world".to_string();
|
||||
|
||||
// A string slice - an immutable view into another string
|
||||
// This is basically an immutable pointer to a string - it doesn’t
|
||||
// actually contain the characters of a string, just a pointer to
|
||||
// A string slice – an immutable view into another string
|
||||
// This is basically an immutable pointer to a string – it doesn’t
|
||||
// actually contain the contents of a string, just a pointer to
|
||||
// something that does (in this case, `s`)
|
||||
let s_slice: &str = s.as_slice();
|
||||
let s_slice: &str = &*s;
|
||||
|
||||
println!("{} {}", s, s_slice); // hello world hello world
|
||||
|
||||
// Vectors/arrays //
|
||||
|
||||
// A fixed-size array
|
||||
let four_ints: [int, ..4] = [1, 2, 3, 4];
|
||||
let four_ints: [i32; 4] = [1, 2, 3, 4];
|
||||
|
||||
// A dynamically-sized vector
|
||||
let mut vector: Vec<int> = vec![1, 2, 3, 4];
|
||||
// A dynamic array (vector)
|
||||
let mut vector: Vec<i32> = vec![1, 2, 3, 4];
|
||||
vector.push(5);
|
||||
|
||||
// A slice - an immutable view into a vector or array
|
||||
// A slice – an immutable view into a vector or array
|
||||
// This is much like a string slice, but for vectors
|
||||
let slice: &[int] = vector.as_slice();
|
||||
let slice: &[i32] = &*vector;
|
||||
|
||||
println!("{} {}", vector, slice); // [1, 2, 3, 4, 5] [1, 2, 3, 4, 5]
|
||||
// Use `{:?}` to print something debug-style
|
||||
println!("{:?} {:?}", vector, slice); // [1, 2, 3, 4, 5] [1, 2, 3, 4, 5]
|
||||
|
||||
// Tuples //
|
||||
|
||||
// A tuple is a fixed-size set of values of possibly different types
|
||||
let x: (i32, &str, f64) = (1, "hello", 3.4);
|
||||
|
||||
// Destructuring `let`
|
||||
let (a, b, c) = x;
|
||||
println!("{} {} {}", a, b, c); // 1 hello 3.4
|
||||
|
||||
// Indexing
|
||||
println!("{}", x.1); // hello
|
||||
|
||||
//////////////
|
||||
// 2. Types //
|
||||
//////////////
|
||||
|
||||
|
||||
// Struct
|
||||
struct Point {
|
||||
x: int,
|
||||
y: int,
|
||||
x: i32,
|
||||
y: i32,
|
||||
}
|
||||
|
||||
let origin: Point = Point { x: 0, y: 0 };
|
||||
|
||||
// Tuple struct
|
||||
struct Point2(int, int);
|
||||
// A struct with unnamed fields, called a ‘tuple struct’
|
||||
struct Point2(i32, i32);
|
||||
|
||||
let origin2 = Point2(0, 0);
|
||||
|
||||
@ -110,16 +134,16 @@ fn main() {
|
||||
Down,
|
||||
}
|
||||
|
||||
let up = Up;
|
||||
let up = Direction::Up;
|
||||
|
||||
// Enum with fields
|
||||
enum OptionalInt {
|
||||
AnInt(int),
|
||||
enum OptionalI32 {
|
||||
AnI32(i32),
|
||||
Nothing,
|
||||
}
|
||||
|
||||
let two: OptionalInt = AnInt(2);
|
||||
let nothing: OptionalInt = Nothing;
|
||||
let two: OptionalI32 = OptionalI32::AnI32(2);
|
||||
let nothing = OptionalI32::Nothing;
|
||||
|
||||
// Generics //
|
||||
|
||||
@ -140,10 +164,10 @@ fn main() {
|
||||
}
|
||||
}
|
||||
|
||||
let a_foo = Foo { bar: 1i };
|
||||
let a_foo = Foo { bar: 1 };
|
||||
println!("{}", a_foo.get_bar()); // 1
|
||||
|
||||
// Traits (interfaces) //
|
||||
// Traits (known as interfaces or typeclasses in other languages) //
|
||||
|
||||
trait Frobnicate<T> {
|
||||
fn frobnicate(self) -> Option<T>;
|
||||
@ -155,30 +179,31 @@ fn main() {
|
||||
}
|
||||
}
|
||||
|
||||
println!("{}", a_foo.frobnicate()); // Some(1)
|
||||
let another_foo = Foo { bar: 1 };
|
||||
println!("{:?}", another_foo.frobnicate()); // Some(1)
|
||||
|
||||
/////////////////////////
|
||||
// 3. Pattern matching //
|
||||
/////////////////////////
|
||||
|
||||
let foo = AnInt(1);
|
||||
|
||||
let foo = OptionalI32::AnI32(1);
|
||||
match foo {
|
||||
AnInt(n) => println!("it’s an int: {}", n),
|
||||
Nothing => println!("it’s nothing!"),
|
||||
OptionalI32::AnI32(n) => println!("it’s an i32: {}", n),
|
||||
OptionalI32::Nothing => println!("it’s nothing!"),
|
||||
}
|
||||
|
||||
// Advanced pattern matching
|
||||
struct FooBar { x: int, y: OptionalInt }
|
||||
let bar = FooBar { x: 15, y: AnInt(32) };
|
||||
struct FooBar { x: i32, y: OptionalI32 }
|
||||
let bar = FooBar { x: 15, y: OptionalI32::AnI32(32) };
|
||||
|
||||
match bar {
|
||||
FooBar { x: 0, y: AnInt(0) } =>
|
||||
FooBar { x: 0, y: OptionalI32::AnI32(0) } =>
|
||||
println!("The numbers are zero!"),
|
||||
FooBar { x: n, y: AnInt(m) } if n == m =>
|
||||
FooBar { x: n, y: OptionalI32::AnI32(m) } if n == m =>
|
||||
println!("The numbers are the same"),
|
||||
FooBar { x: n, y: AnInt(m) } =>
|
||||
FooBar { x: n, y: OptionalI32::AnI32(m) } =>
|
||||
println!("Different numbers: {} {}", n, m),
|
||||
FooBar { x: _, y: Nothing } =>
|
||||
FooBar { x: _, y: OptionalI32::Nothing } =>
|
||||
println!("The second number is Nothing!"),
|
||||
}
|
||||
|
||||
@ -187,19 +212,20 @@ fn main() {
|
||||
/////////////////////
|
||||
|
||||
// `for` loops/iteration
|
||||
let array = [1i, 2, 3];
|
||||
let array = [1, 2, 3];
|
||||
for i in array.iter() {
|
||||
println!("{}", i);
|
||||
}
|
||||
|
||||
for i in range(0u, 10) {
|
||||
// Ranges
|
||||
for i in 0u32..10 {
|
||||
print!("{} ", i);
|
||||
}
|
||||
println!("");
|
||||
// prints `0 1 2 3 4 5 6 7 8 9 `
|
||||
|
||||
// `if`
|
||||
if 1i == 1 {
|
||||
if 1 == 1 {
|
||||
println!("Maths is working!");
|
||||
} else {
|
||||
println!("Oh no...");
|
||||
@ -213,7 +239,7 @@ fn main() {
|
||||
};
|
||||
|
||||
// `while` loop
|
||||
while 1i == 1 {
|
||||
while 1 == 1 {
|
||||
println!("The universe is operating normally.");
|
||||
}
|
||||
|
||||
@ -225,40 +251,49 @@ fn main() {
|
||||
/////////////////////////////////
|
||||
// 5. Memory safety & pointers //
|
||||
/////////////////////////////////
|
||||
|
||||
// Owned pointer - only one thing can ‘own’ this pointer at a time
|
||||
let mut mine: Box<int> = box 3;
|
||||
|
||||
// Owned pointer – only one thing can ‘own’ this pointer at a time
|
||||
// This means that when the `Box` leaves its scope, it can be automatically deallocated safely.
|
||||
let mut mine: Box<i32> = Box::new(3);
|
||||
*mine = 5; // dereference
|
||||
// Here, `now_its_mine` takes ownership of `mine`. In other words, `mine` is moved.
|
||||
let mut now_its_mine = mine;
|
||||
*now_its_mine += 2;
|
||||
println!("{}", now_its_mine); // 7
|
||||
// println!("{}", mine); // this would error
|
||||
|
||||
// Reference - an immutable pointer that refers to other data
|
||||
let mut var = 4i;
|
||||
println!("{}", now_its_mine); // 7
|
||||
// println!("{}", mine); // this would not compile because `now_its_mine` now owns the pointer
|
||||
|
||||
// Reference – an immutable pointer that refers to other data
|
||||
// When a reference is taken to a value, we say that the value has been ‘borrowed’.
|
||||
// While a value is borrowed immutably, it cannot be mutated or moved.
|
||||
// A borrow lasts until the end of the scope it was created in.
|
||||
let mut var = 4;
|
||||
var = 3;
|
||||
let ref_var: &int = &var;
|
||||
let ref_var: &i32 = &var;
|
||||
|
||||
println!("{}", var); // Unlike `box`, `var` can still be used
|
||||
println!("{}", *ref_var);
|
||||
// var = 5; // this would error
|
||||
// *ref_var = 6; // this would too
|
||||
// var = 5; // this would not compile because `var` is borrowed
|
||||
// *ref_var = 6; // this would too, because `ref_var` is an immutable reference
|
||||
|
||||
// Mutable reference
|
||||
let mut var2 = 4i;
|
||||
let ref_var2: &mut int = &mut var2;
|
||||
// While a value is mutably borrowed, it cannot be accessed at all.
|
||||
let mut var2 = 4;
|
||||
let ref_var2: &mut i32 = &mut var2;
|
||||
*ref_var2 += 2;
|
||||
|
||||
println!("{}", *ref_var2); // 6
|
||||
// var2 = 2; // this would error
|
||||
// var2 = 2; // this would not compile because `var2` is borrowed
|
||||
}
|
||||
```
|
||||
|
||||
## Further reading
|
||||
|
||||
There’s a lot more to Rust—this is just the basics of Rust so you can
|
||||
understand the most important things. To learn more about Rust, read [The Rust
|
||||
Guide](http://doc.rust-lang.org/guide.html) and check out the
|
||||
[/r/rust](http://reddit.com/r/rust) subreddit. The folks on the #rust channel
|
||||
on irc.mozilla.org are also always keen to help newcomers.
|
||||
There’s a lot more to Rust—this is just the basics of Rust so you can understand
|
||||
the most important things. To learn more about Rust, read [The Rust Programming
|
||||
Language](http://doc.rust-lang.org/book/index.html) and check out the
|
||||
[/r/rust](http://reddit.com/r/rust) subreddit. The folks on the #rust channel on
|
||||
irc.mozilla.org are also always keen to help newcomers.
|
||||
|
||||
You can also try out features of Rust with an online compiler at the official
|
||||
[Rust playpen](http://play.rust-lang.org) or on the main
|
||||
|
||||
Loading…
Reference in New Issue
Block a user