foundation_core 0.0.3

/// `make_collection` helps generate different underlying rust collection
/// types by providing a macro that will match the underlying types implementation
/// of the From trait
///
/// Directly lifted from <https://stackoverflow.com/questions/27582739/how-do-i-create-a-hashmap-literal>
#[macro_export]
macro_rules! make_collection {
    // map-like
    ($($k:expr => $v:expr),* $(,)?) => {{
        core::convert::From::from([$(($k, $v),)*])
    }};
    // set-like
    ($($v:expr),* $(,)?) => {{
        core::convert::From::from([$($v,)*])
    }};
}

#[cfg(test)]
mod make_map_test {
    use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet};

    #[test]
    fn can_make_vec() {
        let generated: Vec<_> = make_collection![1, 2, 3];
        assert_eq!(vec![1, 2, 3], generated);
    }

    #[test]
    fn can_make_btree_map() {
        let generated: BTreeMap<_, _> = make_collection! { 1 => 2, 3 => 4 };

        let mut expected = BTreeMap::<usize, usize>::new();
        expected.insert(1, 2);
        expected.insert(3, 4);

        assert_eq!(expected, generated)
    }

    #[test]
    fn can_make_hash_map() {
        let generated: HashMap<_, _> = make_collection! { 1 => 2, 3 => 4 };

        let mut expected = HashMap::<usize, usize>::new();
        expected.insert(1, 2);
        expected.insert(3, 4);

        assert_eq!(expected, generated)
    }

    #[test]
    fn can_make_btree_set() {
        let generated: BTreeSet<_> = make_collection! { 1, 2, 3 };

        let mut expected = BTreeSet::<usize>::new();
        expected.insert(1);
        expected.insert(2);
        expected.insert(3);

        assert_eq!(expected, generated)
    }

    #[test]
    fn can_make_hash_set() {
        let generated: HashSet<_> = make_collection! { 1, 2, 3 };

        let mut expected = HashSet::<usize>::new();
        expected.insert(1);
        expected.insert(2);
        expected.insert(3);

        assert_eq!(expected, generated)
    }
}