119 lines
2.2 KiB
C++
119 lines
2.2 KiB
C++
#ifndef value_hh_INCLUDED
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#define value_hh_INCLUDED
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#include <memory>
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#include <unordered_map>
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#include "units.hh"
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namespace Kakoune
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{
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struct bad_value_cast {};
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struct Value
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{
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Value() = default;
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template<typename T>
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Value(const T& val) : m_value{new Model<T>{val}} {}
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template<typename T>
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Value(T&& val) : m_value{new Model<T>{std::move(val)}} {}
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Value(const Value& val)
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{
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if (val.m_value)
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m_value.reset(val.m_value->clone());
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}
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Value(Value&&) = default;
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Value& operator=(const Value& val)
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{
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if (val.m_value)
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m_value.reset(val.m_value->clone());
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else
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m_value.reset();
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return *this;
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}
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Value& operator=(Value&& val) = default;
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explicit operator bool() const { return (bool)m_value; }
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template<typename T>
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bool is_a() const
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{
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return m_value and m_value->type() == typeid(T);
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}
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template<typename T>
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T& as()
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{
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if (not is_a<T>())
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throw bad_value_cast{};
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return static_cast<Model<T>*>(m_value.get())->m_content;
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}
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template<typename T>
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const T& as() const
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{
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return const_cast<Value*>(this)->as<T>();
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}
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private:
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struct Concept
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{
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virtual ~Concept() {}
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virtual const std::type_info& type() const = 0;
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virtual Concept* clone() const = 0;
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};
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template<typename T>
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struct Model : public Concept
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{
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Model(const T& val) : m_content(val) {}
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Model(T&& val) : m_content(std::move(val)) {}
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const std::type_info& type() const override { return typeid(T); }
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Concept* clone() const { return new Model(m_content); }
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T m_content;
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};
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std::unique_ptr<Concept> m_value;
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};
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struct ValueId : public StronglyTypedNumber<ValueId, int>
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{
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constexpr ValueId(int value = 0) : StronglyTypedNumber<ValueId>(value) {}
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static ValueId get_free_id()
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{
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static ValueId next;
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return next++;
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}
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};
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using ValueMap = std::unordered_map<ValueId, Value>;
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}
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namespace std
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{
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template<>
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struct hash<Kakoune::ValueId>
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{
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size_t operator()(Kakoune::ValueId val) const
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{
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return std::hash<int>()((int)val);
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}
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};
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}
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#endif // value_hh_INCLUDED
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