Redefined `Length` in terms of `Apply` and `Fold`

* this function illustrates the use case `Apply` is currently intended for
* moved `Take` and `Nth` into separate files to resolve header resolution conflicts

1 files changed, 31 insertions, 0 deletions

diff --git a/src/list/operation/nth.h b/src/list/operation/nth.h
new file mode 100644
index 0000000..8eb88ba
--- /dev/null
+++ b/src/list/operation/nth.h
@@ -0,0 +1,31 @@
+#ifndef TYPEASVALUE_SRC_LIST_OPERATION_NTH_H_
+#define TYPEASVALUE_SRC_LIST_OPERATION_NTH_H_
+
+#include "operation/math.h"
+
+namespace tav {
+
+template <
+	typename Index,
+	typename Cons
+>
+struct Nth {
+	typedef typename Nth<
+		Substract<Index, Size<1>>,
+		Tail<Cons>
+	>::type type;
+};
+
+template <typename Cons>
+struct Nth<Size<0>, Cons> {
+	typedef Head<Cons> type;
+};
+
+template <typename Index>
+struct Nth<Index, void> {
+	typedef void type;
+};
+
+}
+
+#endif  // TYPEASVALUE_SRC_LIST_OPERATION_NTH_H_