struct Seq[T] {
    ar []T
}

type MapFn[T, K] = fn (T) K

fn (s Seq[T]) map[K](map_fn MapFn[T, K]) Seq[K] {
    mut map_ar := []K{cap: s.ar.len}

    for _, i in s.ar {
        map_ar << map_fn[T, K](i)
    }

    return Seq[K]{map_ar}
}

fn test_generics_method_chaining_call() {
    s := Seq[string]{['one', 'two']}
        .map[int](fn (element string) int {
            match element {
                'one' { return 1 }
                'two' { return 2 }
                else { return -1 }
            }
        })
        .map[int](fn (element int) int {
            return element + 2
        })

    println(s)
    assert s.ar == [3, 4]
}