Implemented higher order function `fold`

* applies a given _function_ to each _Cons_ starting with a initial value
* added appropriate test case

1 files changed, 6 insertions, 0 deletions

diff --git a/test.cc b/test.cc
index f60adbd..e642b3a 100644
--- a/test.cc
+++ b/test.cc
@@ -5,6 +5,7 @@
 #include "conditional/if.h"
 #include "list/cons.h"
 #include "list/list.h"
+#include "list/operation/higher/fold.h"
 
 class TypeAsValueTest : public ::testing::Test { };
 
@@ -83,6 +84,11 @@ TEST_F(TypeAsValueTest, ListConcatenate) {
 	EXPECT_EQ(2, ( tav::Head<tav::Tail<tav::Concatenate<tav::List<tav::Int<1>>::type, tav::List<tav::Int<2>>::type>::type>>::value ));
 }
 
+TEST_F(TypeAsValueTest, ListFold) {
+	// (fold + 0 (list 1 2 3))
+	EXPECT_EQ(6, ( tav::Fold<tav::Add, tav::Int<0>, tav::List<tav::Int<1>, tav::Int<2>, tav::Int<3>>::type>::type::value ));
+}
+
 int main(int argc, char **argv) {
 	testing::InitGoogleTest(&argc, argv);