From 4f2aa4218ec63107b4624e576ff391c2019690a1 Mon Sep 17 00:00:00 2001
From: Adrian Kummerlaender
Date: Sun, 25 Jan 2015 17:15:59 +0100
Subject: Implemented `Count` in terms of `Fold` and `Map` * as its name
 implies this function counts the amount of elements satisfying a given
 _function_ * added appropriate test case

---
 src/list/operation/higher/query.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

(limited to 'src/list')

diff --git a/src/list/operation/higher/query.h b/src/list/operation/higher/query.h
index 29f65dc..c6eabc7 100644
--- a/src/list/operation/higher/query.h
+++ b/src/list/operation/higher/query.h
@@ -3,6 +3,7 @@
 
 #include "fold.h"
 #include "misc.h"
+#include "operation/math.h"
 #include "operation/logic.h"
 
 namespace tav {
@@ -35,6 +36,16 @@ using None = Not<
 	typename Any<Function, List>::type
 >;
 
+template <
+	template<typename> class Function,
+	typename                 List
+>
+using Count = Fold<
+	Add,
+	tav::Size<0>,
+	typename Map<Function, List>::type
+>;
+
 }
 
 #endif  // TYPEASVALUE_SRC_LIST_OPERATION_HIGHER_QUERY_H_
-- 
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