Macro assert_str_range

macro_rules! assert_str_range {
    ($s:expr, $r:expr) => { ... };
}

Asserts that the given range is valid for the given string slice.

The first parameter shall be of a type implementing AsRef<str>. The second parameter shall be of a type implementing the standard library trait RangeBounds<usize>.

The range is valid if it fits within the slice and its bounds are on UTF-8 code point boundaries. If either of these checks fails, panic! is invoked with a description of the failure.

Examples

let s = "Hello";
assert_str_range!(s, ..0);
assert_str_range!(s, 5..);

let r = (..=2);
assert_str_range!(s, r);
let (head, tail) = s.as_bytes().split_at(r.end + 1);

let s = "Привет".to_string();
assert_str_range!(s, ..1); // fails due to splitting a UTF-8 sequence