pipe.rs - rust pipeline macro

pipe.rs

#[macro_export]
macro_rules! pipe {
    // Base case - single function
    ($value:expr, $func:expr) => {
        $func($value)
    };

    // Recursive case - multiple functions
    ($value:expr, $func:expr, $($rest:expr),+) => {
        pipe!($func($value), $($rest),+)
    };
}

// Example usage and tests
#[cfg(test)]
mod tests {
    #[test]
    fn test_pipe_macro() {
        // Test with functions that maintain the same type
        let add_one = |x: i32| x + 1;
        let multiply_by_two = |x: i32| x * 2;
        let subtract_three = |x: i32| x - 3;

        let result = pipe!(5, add_one, multiply_by_two, subtract_three);
        assert_eq!(result, 9); // ((5 + 1) * 2) - 3 = 9

        // Test with functions that change types
        let to_string = |x: i32| x.to_string();
        let add_exclamation = |s: String| s + "!";
        let to_uppercase = |s: String| s.to_uppercase();

        let result = pipe!(42, to_string, add_exclamation, to_uppercase);
        assert_eq!(result, "42!");
    }
}