doc: Syntax highlight the cheatsheet

This commit is contained in:
Brian Anderson 2014-01-07 11:37:45 -08:00
parent aa1839bd69
commit a61d7d6dbe

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@ -6,41 +6,41 @@
Use [`ToStr`](http://static.rust-lang.org/doc/master/std/to_str/trait.ToStr.html).
```rust
~~~
let x: int = 42;
let y: ~str = x.to_str();
```
~~~
**String to int**
Use [`FromStr`](http://static.rust-lang.org/doc/master/std/from_str/trait.FromStr.html), and its helper function, [`from_str`](http://static.rust-lang.org/doc/master/std/from_str/fn.from_str.html).
```rust
~~~
let x: Option<int> = from_str("42");
let y: int = x.unwrap();
```
~~~
**Int to string, in non-base-10**
Use [`ToStrRadix`](http://static.rust-lang.org/doc/master/std/num/trait.ToStrRadix.html).
```rust
~~~
use std::num::ToStrRadix;
let x: int = 42;
let y: ~str = x.to_str_radix(16);
```
~~~
**String to int, in non-base-10**
Use [`FromStrRadix`](http://static.rust-lang.org/doc/master/std/num/trait.FromStrRadix.html), and its helper function, [`from_str_radix`](http://static.rust-lang.org/doc/master/std/num/fn.from_str_radix.html).
```rust
~~~
use std::num::from_str_radix;
let x: Option<int> = from_str_radix("deadbeef", 16);
let y: int = x.unwrap();
```
~~~
# File operations
@ -48,27 +48,27 @@ let y: int = x.unwrap();
Use [`File::open`](http://static.rust-lang.org/doc/master/std/io/fs/struct.File.html#method.open) to create a [`File`](http://static.rust-lang.org/doc/master/std/io/fs/struct.File.html) struct, which implements the [`Reader`](http://static.rust-lang.org/doc/master/std/io/trait.Reader.html) trait.
```rust
~~~
use std::path::Path;
use std::io::fs::File;
let path : Path = Path::new("Doc-FAQ-Cheatsheet.md");
let on_error = || fail!("open of {:?} failed", path);
let reader : File = File::open(&path).unwrap_or_else(on_error);
```
~~~
## How do I iterate over the lines in a file?
Use the [`lines`](http://static.rust-lang.org/doc/master/std/io/trait.Buffer.html#method.lines) method on a [`BufferedReader`](http://static.rust-lang.org/doc/master/std/io/buffered/struct.BufferedReader.html).
```rust
~~~
use std::io::buffered::BufferedReader;
let mut reader = BufferedReader::new(reader);
for line in reader.lines() {
print!("line: {}", line);
}
```
~~~
# String operations
@ -76,10 +76,10 @@ for line in reader.lines() {
Use the [`find_str`](http://static.rust-lang.org/doc/master/std/str/trait.StrSlice.html#tymethod.find_str) method.
```rust
~~~
let str = "Hello, this is some random string";
let index: Option<uint> = str.find_str("rand");
```
~~~
# Containers
@ -87,24 +87,24 @@ let index: Option<uint> = str.find_str("rand");
The [`Container`](http://static.rust-lang.org/doc/master/std/container/trait.Container.html) trait provides the `len` method.
```rust
~~~
let u: ~[u32] = ~[0, 1, 2];
let v: &[u32] = &[0, 1, 2, 3];
let w: [u32, .. 5] = [0, 1, 2, 3, 4];
println!("u: {}, v: {}, w: {}", u.len(), v.len(), w.len()); // 3, 4, 5
```
~~~
## How do I iterate over a vector?
Use the [`iter`](http://static.rust-lang.org/doc/master/std/vec/trait.ImmutableVector.html#tymethod.iter) method.
```rust
~~~
let values: ~[int] = ~[1, 2, 3, 4, 5];
for value in values.iter() { // value: &int
println!("{}", *value);
}
```
~~~
(See also [`mut_iter`](http://static.rust-lang.org/doc/master/std/vec/trait.MutableVector.html#tymethod.mut_iter) which yields `&mut int` and [`move_iter`](http://static.rust-lang.org/doc/master/std/vec/trait.OwnedVector.html#tymethod.move_iter) which yields `int` while consuming the `values` vector.)
@ -112,7 +112,7 @@ for value in values.iter() { // value: &int
## How do I store a function in a struct?
```rust
~~~
struct Foo {
myfunc: fn(int, uint) -> i32
}
@ -131,7 +131,7 @@ fn main() {
println!("{}", (f.myfunc)(1, 2));
println!("{}", (g.myfunc)(3, 4));
}
```
~~~
Note that the parenthesis surrounding `f.myfunc` are necessary: they are how Rust disambiguates field lookup and method call. The `'a` on `FooClosure` is the lifetime of the closure's environment pointer.
@ -139,14 +139,14 @@ Note that the parenthesis surrounding `f.myfunc` are necessary: they are how Rus
[Phantom types](http://www.haskell.org/haskellwiki/Phantom_type) are those that cannot be constructed at compile time. To express these in Rust, zero-variant `enum`s can be used:
```rust
~~~
enum Open {}
enum Closed {}
```
~~~
Phantom types are useful for enforcing state at compile time. For example:
```rust
~~~
struct Door<State>(~str);
fn close(Door(name): Door<Open>) -> Door<Closed> {
@ -159,7 +159,7 @@ fn open(Door(name): Door<Closed>) -> Door<Open> {
let _ = close(Door::<Open>(~"front")); // ok
let _ = close(Door::<Closed>(~"front")); // error: mismatched types: expected `main::Door<main::Open>` but found `main::Door<main::Closed>`
```
~~~
# FFI (Foreign Function Interface)
@ -178,19 +178,19 @@ Note: The Rust signatures should be wrapped in an `extern "ABI" { ... }` block.
You might see things like this in C APIs:
```c
~~~ {.notrust}
typedef struct Window Window;
Window* createWindow(int width, int height);
```
~~~
You can use a zero-element `enum` ([phantom type](#how-do-i-express-phantom-types)) to represent the opaque object handle. The FFI would look like this:
```rust
~~~
enum Window {}
extern "C" {
fn createWindow(width: c_int, height: c_int) -> *Window;
}
```
~~~
Using a phantom type ensures that the handles cannot be (safely) constructed in client code.