diff options
-rw-r--r-- | src/list/operation/basic.h | 35 | ||||
-rw-r--r-- | test.cc | 9 |
2 files changed, 43 insertions, 1 deletions
diff --git a/src/list/operation/basic.h b/src/list/operation/basic.h index cee4cbc..dbd080e 100644 --- a/src/list/operation/basic.h +++ b/src/list/operation/basic.h @@ -2,6 +2,7 @@ #define TYPEASVALUE_SRC_LIST_OPERATION_BASIC_H_ #include "operation/math.h" +#include "conditional/if.h" namespace tav { @@ -26,7 +27,10 @@ struct Nth { typedef If< equal_value<Index, Size<0>>::value, Head<Cons>, - typename Nth<Substract<Index, Size<1>>, Tail<Cons>>::type + typename Nth< + Substract<Index, Size<1>>, + Tail<Cons> + >::type > type; }; @@ -35,6 +39,35 @@ struct Nth<Index, void> { typedef void type; }; +template < + typename Count, + typename Current +> +struct Take { + typedef Cons< + Head<Current>, + typename Take< + Substract<Count, Size<1>>, + Tail<Current> + >::type + > type; +}; + +template <typename Current> +struct Take<Size<0>, Current> { + typedef void type; +}; + +template <typename Count> +struct Take<Count, void> { + typedef void type; +}; + +template <> +struct Take<Size<0>, void> { + typedef void type; +}; + } #endif // TYPEASVALUE_SRC_LIST_OPERATION_BASIC_H_ @@ -62,6 +62,15 @@ TEST_F(TypeAsValueTest, ListNth) { EXPECT_EQ(2, ( tav::Nth<tav::Size<1>, tav::List<tav::Int<1>, tav::Int<2>>::type>::type::value )); } +TEST_F(TypeAsValueTest, ListTake) { + // (length (take 1 (list 1 2))) + EXPECT_EQ(1, ( tav::Length<tav::Take<tav::Size<1>, tav::List<tav::Int<1>, tav::Int<2>>::type>::type>::type::value )); + // (length (take 2 (list 1 2))) + EXPECT_EQ(2, ( tav::Length<tav::Take<tav::Size<2>, tav::List<tav::Int<1>, tav::Int<2>>::type>::type>::type::value )); + // (length (take 3 (list 1 2))) + EXPECT_EQ(2, ( tav::Length<tav::Take<tav::Size<3>, tav::List<tav::Int<1>, tav::Int<2>>::type>::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 )); |