Macro assert_lt

macro_rules! assert_lt {
    ($left:expr, $right:expr $(,)?) => { ... };
    ($left:expr, $right:expr, $($arg:tt)+) => { ... };
}

Asserts that the first expression is less than the second.

Requires that both expressions be comparable with <.

Uses

Assertions are always checked in both debug and release builds, and cannot be disabled. See debug_assert_lt! for assertions that are not enabled in release builds by default.

Custom messages

This macro has a second form, where a custom panic message can be provided with or without arguments for formatting. See std::fmt for syntax for this form.

Examples

assert_lt!(1, 2);

// With a custom message
assert_lt!(4, 5, "Expecting that {} is less than {}", 4, 5);

assert_lt!(5, 5);  // Will panic
assert_lt!(6, 5);

// With a custom message
assert_lt!(6, 5, "Not expecting {} to be less than {}", 6, 5);