diff options
| -rw-r--r-- | src/list/operation/basic.h | 19 | ||||
| -rw-r--r-- | test.cc | 9 |
2 files changed, 28 insertions, 0 deletions
diff --git a/src/list/operation/basic.h b/src/list/operation/basic.h index 1e05a50..cee4cbc 100644 --- a/src/list/operation/basic.h +++ b/src/list/operation/basic.h @@ -1,6 +1,8 @@ #ifndef TYPEASVALUE_SRC_LIST_OPERATION_BASIC_H_ #define TYPEASVALUE_SRC_LIST_OPERATION_BASIC_H_ +#include "operation/math.h" + namespace tav { template <typename Cons> @@ -16,6 +18,23 @@ struct Length<void> { typedef Size<0> type; }; +template < + typename Index, + typename Cons +> +struct Nth { + typedef If< + equal_value<Index, Size<0>>::value, + Head<Cons>, + typename Nth<Substract<Index, Size<1>>, Tail<Cons>>::type + > type; +}; + +template <typename Index> +struct Nth<Index, void> { + typedef void type; +}; + } #endif // TYPEASVALUE_SRC_LIST_OPERATION_BASIC_H_ @@ -53,6 +53,15 @@ TEST_F(TypeAsValueTest, List) { EXPECT_EQ(2, ( tav::Head<tav::Tail<tav::List<tav::Int<1>, tav::Int<2>, tav::Int<3>>::type>>::value )); } +TEST_F(TypeAsValueTest, ListNth) { + // (nth 0 (list 1)) + EXPECT_EQ(1, ( tav::Nth<tav::Size<0>, tav::List<tav::Int<1>>::type>::type::value )); + // (nth 0 (list 1 2)) + EXPECT_EQ(1, ( tav::Nth<tav::Size<0>, tav::List<tav::Int<1>, tav::Int<2>>::type>::type::value )); + // (nth 1 (list 1 2)) + EXPECT_EQ(2, ( tav::Nth<tav::Size<1>, tav::List<tav::Int<1>, tav::Int<2>>::type>::type::value )); +} + TEST_F(TypeAsValueTest, ListConcatenate) { // (length (concatenate (list 1) (list 2))) EXPECT_EQ(2, ( tav::Length<tav::Concatenate<tav::List<tav::Int<1>>::type, tav::List<tav::Int<2>>::type>::type>::type::value )); |