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|
/// Check if an expression matches a refutable pattern.
///
/// Syntax: `matches!(` *expression* `,` *pattern* `)`
///
/// Return a boolean, true if the expression matches the pattern, false otherwise.
///
/// # Examples
///
/// ```
/// #[macro_use]
/// extern crate matches;
///
/// pub enum Foo<T> {
/// A,
/// B(T),
/// }
///
/// impl<T> Foo<T> {
/// pub fn is_a(&self) -> bool {
/// matches!(*self, Foo::A)
/// }
///
/// pub fn is_b(&self) -> bool {
/// matches!(*self, Foo::B(_))
/// }
/// }
///
/// # fn main() { }
/// ```
#[macro_export]
macro_rules! matches {
($expression:expr, $($pattern:tt)+) => {
match $expression {
$($pattern)+ => true,
_ => false
}
}
}
/// Assert that an expression matches a refutable pattern.
///
/// Syntax: `assert_matches!(` *expression* `,` *pattern* `)`
///
/// Panic with a message that shows the expression if it does not match the
/// pattern.
///
/// # Examples
///
/// ```
/// #[macro_use]
/// extern crate matches;
///
/// fn main() {
/// let data = [1, 2, 3];
/// assert_matches!(data.get(1), Some(_));
/// }
/// ```
#[macro_export]
macro_rules! assert_matches {
($expression:expr, $($pattern:tt)+) => {
match $expression {
$($pattern)+ => (),
ref e => panic!("assertion failed: `{:?}` does not match `{}`", e, stringify!($($pattern)+)),
}
}
}
/// Assert that an expression matches a refutable pattern using debug assertions.
///
/// Syntax: `debug_assert_matches!(` *expression* `,` *pattern* `)`
///
/// If debug assertions are enabled, panic with a message that shows the
/// expression if it does not match the pattern.
///
/// When debug assertions are not enabled, this macro does nothing.
///
/// # Examples
///
/// ```
/// #[macro_use]
/// extern crate matches;
///
/// fn main() {
/// let data = [1, 2, 3];
/// debug_assert_matches!(data.get(1), Some(_));
/// }
/// ```
#[macro_export]
macro_rules! debug_assert_matches {
($expression:expr, $($pattern:tt)+) => {
if cfg!(debug_assertions) {
match $expression {
$($pattern)+ => (),
ref e => panic!("assertion failed: `{:?}` does not match `{}`", e, stringify!($($pattern)+)),
}
}
}
}
#[test]
fn matches_works() {
let foo = Some("-12");
assert!(matches!(foo, Some(bar) if
matches!(bar.as_bytes()[0], b'+' | b'-') &&
matches!(bar.as_bytes()[1], b'0'...b'9')
));
}
#[test]
fn assert_matches_works() {
let foo = Some("-12");
assert_matches!(foo, Some(bar) if
matches!(bar.as_bytes()[0], b'+' | b'-') &&
matches!(bar.as_bytes()[1], b'0'...b'9')
);
}
#[test]
#[should_panic(expected = "assertion failed: `Some(\"-AB\")` does not match ")]
fn assert_matches_panics() {
let foo = Some("-AB");
assert_matches!(foo, Some(bar) if
matches!(bar.as_bytes()[0], b'+' | b'-') &&
matches!(bar.as_bytes()[1], b'0'...b'9')
);
}
|
