Macro guard::guard_unwrap

macro_rules! guard_unwrap {
    ($($input:tt)*) => { ... };
}

Match a pattern to an expression, binding identifiers in the calling scope. Panic if the match fails.

Supported syntax:

• let pattern = rhs

Inputs:

• rhs: expression to match against the pattern
• pattern: pattern. See guard for details on which patterns are accepted.

Note that pattern guards are not supported.

#[macro_use] extern crate guard;
guard_unwrap!(let Some(foo) = Some(42));
assert_eq!(foo, 42);

Here’s an example of a failing match that causes [guard_unwrap] to panic.

#[macro_use] extern crate guard;
guard_unwrap!(let Option::None = Some(42));

Note that Option::None is used instead of None to work around the limitations of accepted patterns. See guard for details.

Also note that this macro is mostly provided for destructuring enums in tests. In production code it’s usually better to handle all variants of enums explicitly.