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Diffstat (limited to 'src/sexpr/variant.hpp')
-rw-r--r-- | src/sexpr/variant.hpp | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/src/sexpr/variant.hpp b/src/sexpr/variant.hpp new file mode 100644 index 0000000..04f35dc --- /dev/null +++ b/src/sexpr/variant.hpp @@ -0,0 +1,116 @@ +#pragma once +// variant.hpp - A single value, multiple type container. Better than boost's. +// +// Copyright © 2012 Ben Longbons <b.r.longbons@gmail.com> +// +// This file is part of The Mana World (Athena server) +// +// This program is free software: you can redistribute it and/or modify +// it under the terms of the GNU General Public License as published by +// the Free Software Foundation, either version 3 of the License, or +// (at your option) any later version. +// +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License +// along with this program. If not, see <http://www.gnu.org/licenses/>. + +#include <type_traits> +#include <cstdint> +#include <cstddef> +#include <utility> + +#include "union.hpp" +#include "void.hpp" + +#include "fwd.hpp" + + +namespace tmwa +{ +namespace sexpr +{ +#define JOIN(a, b) a##b + +#define WITH_VAR(ty, var, expr) \ + for (bool JOIN(var, _guard) = true; JOIN(var, _guard); ) \ + for (ty var = expr; JOIN(var, _guard); JOIN(var, _guard) = false) +#define MATCH(expr) \ + WITH_VAR(auto&&, _match_var, expr) \ + switch (tmwa::sexpr::VariantFriend::get_state(_match_var)) +#define CASE(ty, var) \ + break; \ + case tmwa::sexpr::VariantFriend::get_state_for<ty, decltype(_match_var)>(): \ + WITH_VAR(ty, var, tmwa::sexpr::VariantFriend::unchecked_get<ty>(_match_var)) + + template<class... T> + class Variant + { + static_assert(sizeof...(T), "A variant must not be empty"); + }; + template<class D, class... T> + class Variant<D, T...> + { + constexpr static size_t state_count = 1 + sizeof...(T); + + // simplify things immensely + friend class VariantFriend; + + typedef Union<D, T...> DataType; + DataType data; + size_t state; + + void do_destruct(); + template<class C, class... A> + void do_construct(A&&... a); + public: + Variant(); + ~Variant(); + + void reset(); + template<class C, class... A> + void emplace(A&&... a); + + Variant(const Variant& r); + Variant(Variant&& r); + Variant& operator = (const Variant& r); + Variant& operator = (Variant&& r); + + template<class E> + Variant(E e) + { + do_construct<E, E>(std::move(e)); + } + + template<class E> + Variant& operator = (E e) + { + emplace<E, E>(std::move(e)); + return *this; + } + + // use these ONLY if only one type makes sense + // otherwise use apply + template<class E> + bool is() const; + + template<class E> + E *get_if(); + + template<class E> + const E *get_if() const; + }; + + template<class R, class F> + void apply(R& r, F&& f); + template<class R, class F, class V1, class... V> + void apply(R& r, F&& f, V1&& v1, V&&... v); + template<class F, class... V> + void apply(Void&& r, F&& f, V&&... v); +} // namespace sexpr +} // namespace tmwa + +#include "variant.tcc" |