function_types.bt

type CheckInt := fun (i i32) bool

// You can use the alias like any other type, for example as parameter
fun check_nums(nums []i32, c CheckInt) {
	for n in nums {
		if c(n) {
			println(n)
		}
	}
}

// This implicitly matches the signature of `CheckInt`
fun greater_two(n i32) bool {
	return n > 2
}

fun main() {
	// You can use `greater_two` everywhere, where `CheckInt` is expected
	check_nums([2, 3, 4], greater_two)

	// Anonymous functions work as well
	check_nums([1, 2, 3, 4], fun (n i32) bool {
		return n % 2 == 0
	})
}