Implemented `Contains` in terms of `Any`

* as its name implies this _function_ simplifies checking if a specific value is contained within a given list
* updated `Map` to actually resolve the provided _function_

4 files changed, 56 insertions, 1 deletions

diff --git a/src/list/operation/contains.h b/src/list/operation/contains.h
new file mode 100644
index 0000000..9e752ed
--- /dev/null
+++ b/src/list/operation/contains.h
@@ -0,0 +1,26 @@
+#ifndef TYPEASVALUE_SRC_LIST_OPERATION_CONTAINS_H_
+#define TYPEASVALUE_SRC_LIST_OPERATION_CONTAINS_H_
+
+#include "higher/query.h"
+
+namespace tav {
+
+template <
+	typename Element,
+	typename List
+>
+class Contains {
+	private:
+		template <typename Current>
+		struct comparator {
+			typedef std::is_same<Current, Element> type;
+		};
+
+	public:
+		typedef typename Any<comparator, List>::type type;
+
+};
+
+}
+
+#endif  // TYPEASVALUE_SRC_LIST_OPERATION_CONTAINS_H_
diff --git a/src/list/operation/higher/misc.h b/src/list/operation/higher/misc.h
index 1eacaaa..feec7de 100644
--- a/src/list/operation/higher/misc.h
+++ b/src/list/operation/higher/misc.h
@@ -17,7 +17,10 @@ class Map {
 			typename Previous
 		>
 		struct function_wrapper {
-			typedef Cons<Function<Current>, Previous> type;
+			typedef Cons<
+				typename Function<Current>::type,
+				Previous
+			> type;
 		};
 
 	public:
diff --git a/src/list/operation/higher/query.h b/src/list/operation/higher/query.h
index 34d05cb..29f65dc 100644
--- a/src/list/operation/higher/query.h
+++ b/src/list/operation/higher/query.h
@@ -2,6 +2,7 @@
 #define TYPEASVALUE_SRC_LIST_OPERATION_HIGHER_QUERY_H_
 
 #include "fold.h"
+#include "misc.h"
 #include "operation/logic.h"
 
 namespace tav {
diff --git a/test.cc b/test.cc
index 49b95cb..718fb70 100644
--- a/test.cc
+++ b/test.cc
@@ -6,6 +6,7 @@
 #include "list/cons.h"
 #include "list/list.h"
 #include "list/operation/reverse.h"
+#include "list/operation/contains.h"
 #include "list/operation/higher/fold.h"
 #include "list/operation/higher/misc.h"
 #include "list/operation/higher/query.h"
@@ -466,3 +467,27 @@ static_assert(
 	>::value,
 	"(none even? (list 2 3 5)) != #f"
 );
+
+// list contains
+
+static_assert(
+	std::is_same<
+		tav::Boolean<true>,
+		tav::Contains<
+			tav::Int<2>,
+			tav::List<tav::Int<1>, tav::Int<2>, tav::Int<3>>::type
+		>::type
+	>::value,
+	"(contains 2 (list 1 2 3)) != #t"
+);
+
+static_assert(
+	std::is_same<
+		tav::Boolean<false>,
+		tav::Contains<
+			tav::Int<0>,
+			tav::List<tav::Int<1>, tav::Int<2>, tav::Int<3>>::type
+		>::type
+	>::value,
+	"(contains 0 (list 1 2 3)) != #f"
+);