更多 sscanf 功能的示例

use sscanf::sscanf;
use std::num::NonZeroUsize;

let input = "<x=3, y=-6, z=6>";
let parsed = sscanf!(input, "<x={i32}, y={i32}, z={i32}>");
assert_eq!(parsed.unwrap(), (3, -6, 6));

let input = "Move to N36E21";
let parsed = sscanf!(input, "Move to {char}{usize}{char}{usize}");
assert_eq!(parsed.unwrap(), ('N', 36, 'E', 21));

let input = "Escape literal { } as {{ and }}";
let parsed = sscanf!(input, "Escape literal {{ }} as {{{{ and }}}}");
assert_eq!(parsed.unwrap(), ());

let input = "Indexing types: N36E21";
let parsed = sscanf!(input, "Indexing types: {1}{0}{1}{0}", NonZeroUsize, char);
// output is in the order of the placeholders
assert_eq!(parsed.unwrap(), ('N', NonZeroUsize::new(36).unwrap(),
                             'E', NonZeroUsize::new(21).unwrap()));

let input = "A Sentence with Spaces. Another Sentence.";
// str and String do the same, but String clones from the input string
// to take ownership instead of borrowing.
let (a, b) = sscanf!(input, "{String}. {str}.").unwrap();
assert_eq!(a, "A Sentence with Spaces");
assert_eq!(b, "Another Sentence");

// Number format options
let input = "ab01  127  101010  1Z";
let parsed = sscanf!(input, "{usize:x}  {i32:o}  {u8:b}  {u32:r36}");
let (a, b, c, d) = parsed.unwrap();
assert_eq!(a, 0xab01);     // Hexadecimal
assert_eq!(b, 0o127);      // Octal
assert_eq!(c, 0b101010);   // Binary

assert_eq!(d, 71);         // any radix (r36 = Radix 36)
assert_eq!(d, u32::from_str_radix("1Z", 36).unwrap());

let input = "color: #D4AF37";
// Number types take their size into account, and hexadecimal u8 can
// have at most 2 digits => only possible match is 2 digits each.
let (r, g, b) = sscanf!(input, "color: #{u8:x}{u8:x}{u8:x}").unwrap();
assert_eq!((r, g, b), (0xD4, 0xAF, 0x37));

在这个情况下，输入是一个 &'static str，但也可以是 String、&str、&String、等等。基本上，任何具有 Deref<Target=str> 并且不拥有所有权的对象。有关可能输入的几个示例，请参阅此处。

let input = "random Text";
let parsed = sscanf::sscanf!(input, "{str:/[^m]+/}{str}");

// regex  [^m]+  matches anything that isn't an 'm'
// => stops at the 'm' in 'random'
assert_eq!(parsed.unwrap(), ("rando", "m Text"));

use sscanf::sscanf;
let input = "1234";
let parsed = sscanf!(input, r"{u8:/\d{2}/}{u8}"); // regex  \d{2}  matches 2 digits
let _ =      sscanf!(input, "{u8:/\\d{2}/}{u8}"); // the same with a non-raw string
assert_eq!(parsed.unwrap(), (12, 34));

#[derive(sscanf::FromScanf)]
#[sscanf(format = "#{r:x}{g:x}{b:x}")] // matches '#' followed by 3 hexadecimal u8s
struct Color {
    r: u8,
    g: u8,
    b: u8,
}

let input = "color: #ff00cc";
let parsed = sscanf::sscanf!(input, "color: {Color}").unwrap();
assert!(matches!(parsed, Color { r: 0xff, g: 0x00, b: 0xcc }));

#[derive(sscanf::FromScanf)]
enum HasChanged {
    #[sscanf(format = "received {added} additions and {deleted} deletions")]
    Yes {
        added: usize,
        deleted: usize,
    },
    #[sscanf("has not changed")] // the `format =` part can be omitted
    No
}

let input = "Your file has not changed since your last visit!";
let parsed = sscanf::sscanf!(input, "Your file {HasChanged} since your last visit!").unwrap();
assert!(matches!(parsed, HasChanged::No));

let input = "Your file received 325 additions and 15 deletions since your last visit!";
let parsed = sscanf::sscanf!(input, "Your file {HasChanged} since your last visit!").unwrap();
assert!(matches!(parsed, HasChanged::Yes { added: 325, deleted: 15 }));