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diff --git a/rust.html.markdown b/rust.html.markdown new file mode 100644 index 00000000..0b9a5e58 --- /dev/null +++ b/rust.html.markdown @@ -0,0 +1,265 @@ +--- +language: rust +contributors: + - ["P1start", "http://p1start.github.io/"] +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. + +Although Rust is a relatively low-level language, Rust has some functional +concepts that are generally found in higher-level languages. This makes +Rust not only fast, but also easy and efficient to code in. + +```rust +// This is a comment. Single-line look like this... +/* ...and multi-line comment look like this */ + +/////////////// +// 1. Basics // +/////////////// + +// Functions +fn add2(x: int, y: int) -> int { + // Implicit return (no semicolon) + x + y +} + +// Main function +fn main() { + // Numbers // + + // Immutable bindings + let x: int = 1; + + // Integer/float suffixes + let y: int = 13i; + let f: f64 = 1.3f64; + + // Type inference + let implicit_x = 1i; + let implicit_f = 1.3f64; + + // Maths + let sum = x + y + 13i; + + // Mutable variable + let mut mutable = 1; + mutable += 2; + + // Strings // + + // String literals + let x: &'static str = "hello world!"; + + // Printing + println!("{} {}", f, x); // 1.3 hello world + + // 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 + // something that does (in this case, `s`) + let s_slice: &str = s.as_slice(); + + println!("{} {}", s, s_slice); // hello world hello world + + // Vectors/arrays // + + // A fixed-size array + let four_ints: [int, ..4] = [1, 2, 3, 4]; + + // A dynamically-sized vector + let mut vector: Vec<int> = vec![1, 2, 3, 4]; + vector.push(5); + + // 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(); + + println!("{} {}", vector, slice); // [1, 2, 3, 4, 5] [1, 2, 3, 4, 5] + + ////////////// + // 2. Types // + ////////////// + + // Struct + struct Point { + x: int, + y: int, + } + + let origin: Point = Point { x: 0, y: 0 }; + + // Tuple struct + struct Point2(int, int); + + let origin2 = Point2(0, 0); + + // Basic C-like enum + enum Direction { + Left, + Right, + Up, + Down, + } + + let up = Up; + + // Enum with fields + enum OptionalInt { + AnInt(int), + Nothing, + } + + let two: OptionalInt = AnInt(2); + let nothing: OptionalInt = Nothing; + + // Generics // + + struct Foo<T> { bar: T } + + // This is defined in the standard library as `Option` + enum Optional<T> { + SomeVal(T), + NoVal, + } + + // Methods // + + impl<T> Foo<T> { + // Methods take an explicit `self` parameter + fn get_bar(self) -> T { + self.bar + } + } + + let a_foo = Foo { bar: 1i }; + println!("{}", a_foo.get_bar()); // 1 + + // Traits (interfaces) // + + trait Frobnicate<T> { + fn frobnicate(self) -> Option<T>; + } + + impl<T> Frobnicate<T> for Foo<T> { + fn frobnicate(self) -> Option<T> { + Some(self.bar) + } + } + + println!("{}", a_foo.frobnicate()); // Some(1) + + ///////////////////////// + // 3. Pattern matching // + ///////////////////////// + + let foo = AnInt(1); + match foo { + AnInt(n) => println!("it’s an int: {}", n), + Nothing => println!("it’s nothing!"), + } + + // Advanced pattern matching + struct FooBar { x: int, y: OptionalInt } + let bar = FooBar { x: 15, y: AnInt(32) }; + + match bar { + FooBar { x: 0, y: AnInt(0) } => + println!("The numbers are zero!"), + FooBar { x: n, y: AnInt(m) } if n == m => + println!("The numbers are the same"), + FooBar { x: n, y: AnInt(m) } => + println!("Different numbers: {} {}", n, m), + FooBar { x: _, y: Nothing } => + println!("The second number is Nothing!"), + } + + ///////////////////// + // 4. Control flow // + ///////////////////// + + // `for` loops/iteration + let array = [1i, 2, 3]; + for i in array.iter() { + println!("{}", i); + } + + for i in range(0u, 10) { + print!("{} ", i); + } + println!(""); + // prints `0 1 2 3 4 5 6 7 8 9 ` + + // `if` + if 1i == 1 { + println!("Maths is working!"); + } else { + println!("Oh no..."); + } + + // `if` as expression + let value = if true { + "good" + } else { + "bad" + }; + + // `while` loop + while 1i == 1 { + println!("The universe is operating normally."); + } + + // Infinite loop + loop { + println!("Hello!"); + } + + ///////////////////////////////// + // 5. Memory safety & pointers // + ///////////////////////////////// + + // Owned pointer - only one thing can ‘own’ this pointer at a time + let mut mine: Box<int> = box 3; + *mine = 5; // dereference + 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; + var = 3; + let ref_var: &int = &var; + println!("{}", var); // Unlike `box`, `var` can still be used + println!("{}", *ref_var); + // var = 5; // this would error + // *ref_var = 6; // this would too + + // Mutable reference + let mut var2 = 4i; + let ref_var2: &mut int = &mut var2; + *ref_var2 += 2; + println!("{}", *ref_var2); // 6 + // var2 = 2; // this would error +} +``` + +## 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 tutorial](http://doc.rust-lang.org/tutorial.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 +[Rust website](http://rust-lang.org). |