Macro ensure 

macro_rules! ensure {
    ($cond:expr, $msg:literal) => { ... };
    ($cond:expr, $err:expr) => { ... };
    ($cond:expr, $fmt:expr, $($arg:tt)*) => { ... };
}

Ensures a condition is true; otherwise returns an Error.

Examples

use fory_core::ensure;
use fory_core::error::Error;

fn check_value(n: i32) -> Result<(), Error> {
    ensure!(n > 0, "value must be positive");
    ensure!(n < 10, "value {} too large", n);
    Ok(())
}