diff options
| -rw-r--r-- | src/list/operation/higher/query.h | 11 | ||||
| -rw-r--r-- | test.cc | 24 |
2 files changed, 35 insertions, 0 deletions
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_ @@ -607,3 +607,27 @@ static_assert( >::value, "(list-tabulate 4 square) != (list 0 1 4 9)" ); + +// list count + +static_assert( + std::is_same< + tav::Size<2>, + tav::Count< + tav::Odd, + tav::List<tav::Int<1>, tav::Int<2>, tav::Int<3>>::type + >::type + >::value, + "(count odd? (list 1 2 3)) != 2" +); + +static_assert( + std::is_same< + tav::Size<0>, + tav::Count< + tav::Even, + tav::List<tav::Int<1>, tav::Int<3>, tav::Int<5>>::type + >::type + >::value, + "(count even? (list 1 3 5)) != 0" +); |