Implemented higher order `Find` list search operation

* added appropriate test case
* other queries in `query.h` may be redefined in terms of `Find`

1 files changed, 30 insertions, 0 deletions

diff --git a/src/list/operation/higher/find.h b/src/list/operation/higher/find.h
new file mode 100644
index 0000000..47b88ad
--- /dev/null
+++ b/src/list/operation/higher/find.h
@@ -0,0 +1,30 @@
+#ifndef TYPEASVALUE_SRC_LIST_OPERATION_HIGHER_FIND_H_
+#define TYPEASVALUE_SRC_LIST_OPERATION_HIGHER_FIND_H_
+
+#include "type.h"
+#include "conditional/if.h"
+
+namespace tav {
+
+template <
+	template<typename> class Predicate,
+	typename                 Current
+>
+struct Find {
+	typedef If<
+		Predicate<Head<Current>>::type::value,
+		Head<Current>,
+		typename Find<Predicate, Tail<Current>>::type
+	> type;
+};
+
+template <
+	template<typename> class Predicate
+>
+struct Find<Predicate, void> {
+	typedef Boolean<false> type;
+};
+
+}
+
+#endif  // TYPEASVALUE_SRC_LIST_OPERATION_HIGHER_FIND_H_