Macro extract_matches

macro_rules! extract_matches {
    ($e:expr, $variant:path) => { ... };
    ( $e:expr , $variant:path , $($arg:tt)* ) => { ... };
}

Macro to verify an expression matches a pattern and extract its fields.

Examples:

use cairo_lang_utils::extract_matches;

#[derive(Debug, Clone, Copy)]
struct Point {
    x: u32,
    y: u32,
}
#[derive(Debug)]
enum MyEnum {
    Point(Point),
    Value(u32),
}
let p = MyEnum::Point(Point { x: 3, y: 5 });
let Point { x, y: _ } = extract_matches!(p, MyEnum::Point);
assert_eq!(x, 3);

// Would panic with 'assertion failed: `Point(Point { x: 3, y: 5 })` does not match `MyEnum::Value`:
// Expected a point!'
// let _value = extract_matches!(p, MyEnum::Value, "Expected a point!");