diff options
| -rw-r--r-- | compat/meta.hpp | 53 | ||||
| -rw-r--r-- | compat/util.hpp | 1 |
2 files changed, 54 insertions, 0 deletions
diff --git a/compat/meta.hpp b/compat/meta.hpp new file mode 100644 index 00000000..b1c1dd1a --- /dev/null +++ b/compat/meta.hpp @@ -0,0 +1,53 @@ +#pragma once + +#include <tuple> + +namespace meta { + +namespace detail { + + template<typename x, typename y> + struct reverse_; + + template<typename x0, typename... xs, template<typename...> class x, typename... ys> + struct reverse_<x<x0, xs...>, x<ys...>> + { + using type = typename reverse_<x<xs...>, x<x0, ys...>>::type; + }; + + template<template<typename...> class x, typename... ys> + struct reverse_<x<>, x<ys...>> + { + using type = x<ys...>; + }; + + template<template<typename...> class inst, typename x> + struct lift_; + + template<template<typename...> class inst, template<typename...> class x, typename... xs> + struct lift_<inst, x<xs...>> + { + using type = inst<xs...>; + }; +} + + +template<typename... xs> +using reverse = typename detail::reverse_<std::tuple<xs...>, std::tuple<>>::type; + +template<template<typename...> class inst, class x> +using lift = typename detail::lift_<inst, x>::type; + +template<typename x, typename... xs> +using first = x; + +template<typename x, typename... xs> +using rest = std::tuple<xs...>; + +template<typename... xs> +using butlast = reverse<rest<reverse<xs...>>>; + +template<typename... xs> +using last = lift<first, reverse<xs...>>; + +} diff --git a/compat/util.hpp b/compat/util.hpp index 60427b53..3adebd5b 100644 --- a/compat/util.hpp +++ b/compat/util.hpp @@ -2,6 +2,7 @@ #include "ndebug-guard.hpp" #include "run-in-thread.hpp" +#include "meta.hpp" #include <memory> #include <cmath> |