Macro assertables::assure_fn_lt

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

Assure one function output is less than to another function output.

• When true, return Ok(true).

• When false, return Ok(false).

• Otherwise, return Err with a message and the values of the expressions with their debug representations.

Examples

let x: Result<bool, &str> = assure_fn_lt!(i32::abs, 1 as i32, -2 as i32);
//-> Ok(true)

let x: Result<bool, &str> = assure_fn_lt!(i32::abs, -2 as i32, 1 as i32);
//-> Ok(false)

This macro has a second form where a custom message can be provided.