arguments_optional.rs

// Create a function that sums two arguments together. If only one argument is provided,
// then return a function that expects one argument and returns the sum.
//
// For example, addTogether(2, 3) should return 5, and addTogether(2) should return a function.
//
// Calling this returned function with a single argument will then return the sum:
//
// var sumTwoAnd = addTogether(2);
//
// sumTwoAnd(3) returns 5.
//
// If either argument isn't a valid number, return undefined.

#[allow(dead_code)]
fn curry(a: i32) -> impl Fn(i32) -> i32 {
    move |x| a + x
}

#[allow(dead_code)]
fn add_two(a: i32, b: i32) -> i32 {
    a + b
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test1() {
        assert_eq!(add_two(2, 3), 5);
    }

    #[test]
    fn test2() {
        assert_eq!(add_two(23, 30), 53);
    }

    #[test]
    fn test3() {
        let add_five = curry(5);

        assert_eq!(add_five(7), 12);
    }

    #[test]
    fn test4() {
        let add_twentyfive = curry(25);

        assert_eq!(add_twentyfive(50), 75);
    }
}