[Feat] 详细区分左值(LvObject)与右值(RvObject -> ObjectPtr)

[Impl] 重构evaluator.cpp + hpp 全部
[Feat] 增加对于IndexExpr的解析
[Fix][Impl] 现在点运算符不由BinaryExpr负责,增加MemberExpr,单独实现解析
[Impl] 项目目录全部翻修, src/目录下单独文件夹放置每一个模块

src/Value/Type.hpp

@@ -0,0 +1,67 @@
+#pragma once
+
+#include <Core/fig_string.hpp>
+
+#include <variant>
+#include <map>
+
+namespace Fig
+{
+
+    class TypeInfo final
+    {
+    private:
+        size_t id;
+
+    public:
+        FString name;
+
+        FString toString() const
+        {
+            return name;
+        }
+
+        static std::map<FString, size_t> typeMap;
+
+        static size_t getID(FString _name)
+        {
+            return typeMap.at(_name);
+        }
+        size_t getInstanceID(FString _name) const
+        {
+            return id;
+        }
+
+        TypeInfo();
+        TypeInfo(FString _name, bool reg = false);
+        TypeInfo(const TypeInfo &other) = default;
+
+        bool operator==(const TypeInfo &other) const
+        {
+            return id == other.id;
+        }
+    };
+
+    // class Value;
+    namespace ValueType
+    {
+        extern const TypeInfo Any;
+        extern const TypeInfo Null;
+        extern const TypeInfo Int;
+        extern const TypeInfo String;
+        extern const TypeInfo Bool;
+        extern const TypeInfo Double;
+        extern const TypeInfo Function;
+        extern const TypeInfo StructType;
+        extern const TypeInfo StructInstance;
+        extern const TypeInfo List;
+        extern const TypeInfo Map;
+        extern const TypeInfo Tuple;
+
+        using IntClass = int64_t;
+        using DoubleClass = double;
+        using BoolClass = bool;
+        using NullClass = std::monostate;
+        using StringClass = FString;
+    }; // namespace ValueType
+}; // namespace Fig

src/Value/containers.hpp

@@ -0,0 +1,6 @@
+#pragma once
+
+namespace Fig
+{
+    
+};

src/Value/function.hpp

@@ -0,0 +1,67 @@
+#pragma once
+
+#include <Ast/functionParameters.hpp>
+#include <Context/context_forward.hpp>
+
+#include <atomic>
+#include <functional>
+#include <memory>
+#include <vector>
+
+namespace Fig
+{
+    class Object;
+    class Function
+    {
+    public:
+        std::size_t id;
+        Ast::FunctionParameters paras;
+        TypeInfo retType;
+        Ast::BlockStatement body;
+
+        bool isBuiltin = false;
+        std::function<std::shared_ptr<Object>(const std::vector<std::shared_ptr<Object>> &)> builtin;
+        int builtinParamCount = -1;
+
+        std::shared_ptr<Context> closureContext;
+
+        // ===== Constructors =====
+        Function() :
+            id(nextId()) {}
+
+        Function(Ast::FunctionParameters _paras, TypeInfo _retType, Ast::BlockStatement _body, ContextPtr _closureContext) :
+            id(nextId()), // 分配唯一 ID
+            paras(std::move(_paras)),
+            retType(std::move(_retType)),
+            body(std::move(_body)),
+            closureContext(std::move(_closureContext))
+        {
+        }
+
+        Function(std::function<std::shared_ptr<Object>(const std::vector<std::shared_ptr<Object>> &)> fn, int argc) :
+            id(nextId()), isBuiltin(true), builtin(fn), builtinParamCount(argc) {}
+
+        // ===== Copy / Move =====
+        Function(const Function &other) = default;
+        Function(Function &&) noexcept = default;
+        Function &operator=(const Function &) = default;
+        Function &operator=(Function &&) noexcept = default;
+
+        // ===== Comparison =====
+        bool operator==(const Function &other) const noexcept
+        {
+            return id == other.id;
+        }
+        bool operator!=(const Function &other) const noexcept
+        {
+            return !(*this == other);
+        }
+
+    private:
+        static std::size_t nextId()
+        {
+            static std::atomic<std::size_t> counter{1};
+            return counter++;
+        }
+    };
+} // namespace Fig

src/Value/structInstance.hpp

@@ -0,0 +1,31 @@
+#pragma once
+
+#include <Context/context_forward.hpp>
+
+namespace Fig
+{
+    struct StructInstance
+    {
+        size_t parentId;
+        ContextPtr localContext;
+
+        // ===== Constructors =====
+        StructInstance(size_t _parentId, ContextPtr _localContext) :
+            parentId(_parentId), localContext(std::move(_localContext)) {}
+
+        StructInstance(const StructInstance &other) = default;
+        StructInstance(StructInstance &&) noexcept = default;
+        StructInstance &operator=(const StructInstance &) = default;
+        StructInstance &operator=(StructInstance &&) noexcept = default;
+
+        // ===== Comparison =====
+        bool operator==(const StructInstance &other) const noexcept
+        {
+            return parentId == other.parentId && localContext == other.localContext;
+        }
+        bool operator!=(const StructInstance &other) const noexcept
+        {
+            return !(*this == other);
+        }
+    };
+} // namespace Fig

src/Value/structType.hpp

@@ -0,0 +1,67 @@
+#pragma once
+
+#include <Core/fig_string.hpp>
+#include <Ast/Statements/StructDefSt.hpp>
+
+#include <Value/Type.hpp>
+
+#include <Context/context_forward.hpp>
+#include <atomic>
+#include <vector>
+
+namespace Fig
+{
+    struct Field
+    {
+        AccessModifier am;
+        FString name;
+        TypeInfo type;
+        Ast::Expression defaultValue;
+
+        Field(AccessModifier _am, FString _name, TypeInfo _type, Ast::Expression _defaultValue) :
+            am(_am), name(std::move(_name)), type(std::move(_type)), defaultValue(std::move(_defaultValue)) {}
+
+        bool isPublic() const
+        {
+            return am == AccessModifier::Public || am == AccessModifier::PublicConst;
+        }
+        bool isConst() const
+        {
+            return am == AccessModifier::Const || am == AccessModifier::PublicConst;
+        }
+
+    };
+
+    struct StructType
+    {
+        std::size_t id;
+        ContextPtr defContext; // 定义时的上下文
+        std::vector<Field> fields;
+
+        // ===== Constructors =====
+        StructType(ContextPtr _defContext, std::vector<Field> _fields) :
+            id(nextId()), defContext(std::move(_defContext)), fields(std::move(_fields)) {}
+
+        StructType(const StructType &other) = default;
+        StructType(StructType &&) noexcept = default;
+        StructType &operator=(const StructType &) = default;
+        StructType &operator=(StructType &&) noexcept = default;
+
+        // ===== Comparison =====
+        bool operator==(const StructType &other) const noexcept
+        {
+            return id == other.id;
+        }
+        bool operator!=(const StructType &other) const noexcept
+        {
+            return !(*this == other);
+        }
+
+    private:
+        static std::size_t nextId()
+        {
+            static std::atomic<std::size_t> counter{1};
+            return counter++;
+        }
+    };
+} // namespace Fig

src/Value/value.cpp

@@ -0,0 +1,40 @@
+#include <Value/value.hpp>
+#include <Context/context.hpp>
+
+// #include <iostream>
+
+namespace Fig
+{
+    std::map<FString, size_t> TypeInfo::typeMap = {};
+
+    TypeInfo::TypeInfo() :                              // only allow use in evaluate time !! <---- dynamic type system requirement
+        id(1), name(FString(u8"Any")) {}
+    TypeInfo::TypeInfo(FString _name, bool reg)
+    {
+        static size_t id_count = 0;
+        name = std::move(_name);
+        // std::cerr << "TypeInfo constructor called for type name: " << name.toBasicString() << "\n";
+        if (reg)
+        {
+            typeMap[name] = ++id_count;
+            id = id_count;
+        }
+        else
+        {
+            id = typeMap.at(name); // may throw
+        }
+    }
+    
+    const TypeInfo ValueType::Any(FString(u8"Any"), true);           // id: 1
+    const TypeInfo ValueType::Null(FString(u8"Null"), true);         // id: 2
+    const TypeInfo ValueType::Int(FString(u8"Int"), true);           // id: 3
+    const TypeInfo ValueType::String(FString(u8"String"), true);     // id: 4
+    const TypeInfo ValueType::Bool(FString(u8"Bool"), true);         // id: 5
+    const TypeInfo ValueType::Double(FString(u8"Double"), true);     // id: 6
+    const TypeInfo ValueType::Function(FString(u8"Function"), true); // id: 7
+    const TypeInfo ValueType::StructType(FString(u8"StructType"), true);     // id: 8
+    const TypeInfo ValueType::StructInstance(FString(u8"StructInstance"), true); // id: 9
+    const TypeInfo ValueType::List(FString(u8"List"), true); // id: 10
+    const TypeInfo ValueType::Map(FString(u8"Map"), true); // id: 11
+    const TypeInfo ValueType::Tuple(FString(u8"Tuple"), true); // id: 12
+} // namespace Fig

src/Value/value.hpp

@@ -0,0 +1,453 @@
+#pragma once
+#include <Value/function.hpp>
+#include <Value/structType.hpp>
+#include <Value/structInstance.hpp>
+#include <Value/Type.hpp>
+#include <Value/valueError.hpp>
+
+#include <variant>
+#include <cmath>
+#include <string>
+#include <format>
+
+namespace Fig
+{
+    inline bool isDoubleInteger(ValueType::DoubleClass d)
+    {
+        return std::floor(d) == d;
+    }
+
+    inline bool isNumberExceededIntLimit(ValueType::DoubleClass d)
+    {
+        static constexpr auto intMaxAsDouble =
+            static_cast<ValueType::DoubleClass>(std::numeric_limits<ValueType::IntClass>::max());
+
+        static constexpr auto intMinAsDouble =
+            static_cast<ValueType::DoubleClass>(std::numeric_limits<ValueType::IntClass>::min());
+        return d > intMaxAsDouble || d < intMinAsDouble;
+    }
+
+    class Object
+    {
+    public:
+        using VariantType = std::variant<
+            ValueType::NullClass,
+            ValueType::IntClass,
+            ValueType::DoubleClass,
+            ValueType::StringClass,
+            ValueType::BoolClass,
+            Function,
+            StructType,
+            StructInstance>;
+
+        VariantType data;
+
+        Object() :
+            data(ValueType::NullClass{}) {}
+        Object(const ValueType::NullClass &n) :
+            data(n) {}
+        Object(const ValueType::IntClass &i) :
+            data(i) {}
+        explicit Object(const ValueType::DoubleClass &d) :
+            data(d)
+        {
+        }
+        Object(const ValueType::StringClass &s) :
+            data(s) {}
+        Object(const ValueType::BoolClass &b) :
+            data(b) {}
+        Object(const Function &f) :
+            data(f) {}
+        Object(const StructType &s) :
+            data(s) {}
+        Object(const StructInstance &s) :
+            data(s) {}
+
+        Object(const Object &) = default;
+        Object(Object &&) noexcept = default;
+        Object &operator=(const Object &) = default;
+        Object &operator=(Object &&) noexcept = default;
+
+        static Object defaultValue(TypeInfo ti)
+        {
+            if (ti == ValueType::Int)
+                return Object(ValueType::IntClass(0));
+            else if (ti == ValueType::Double)
+                return Object(ValueType::DoubleClass(0.0));
+            else if (ti == ValueType::String)
+                return Object(ValueType::StringClass(u8""));
+            else if (ti == ValueType::Bool)
+                return Object(ValueType::BoolClass(false));
+            else
+                return *getNullInstance();
+        }
+
+        template <typename T>
+        bool is() const
+        {
+            return std::holds_alternative<T>(data);
+        }
+
+        template <typename T>
+        T &as()
+        {
+            return std::get<T>(data);
+        }
+
+        template <typename T>
+        const T &as() const
+        {
+            return std::get<T>(data);
+        }
+
+        static std::shared_ptr<Object> getNullInstance()
+        {
+            static std::shared_ptr<Object> n = std::make_shared<Object>(ValueType::NullClass{});
+            return n;
+        }
+        static std::shared_ptr<Object> getTrueInstance()
+        {
+            static std::shared_ptr<Object> t = std::make_shared<Object>(true);
+            return t;
+        }
+        static std::shared_ptr<Object> getFalseInstance()
+        {
+            static std::shared_ptr<Object> f = std::make_shared<Object>(false);
+            return f;
+        }
+
+        TypeInfo getTypeInfo() const
+        {
+            return std::visit([](auto &&val) -> TypeInfo {
+                using T = std::decay_t<decltype(val)>;
+                if constexpr (std::is_same_v<T, ValueType::NullClass>)
+                    return ValueType::Null;
+                else if constexpr (std::is_same_v<T, ValueType::IntClass>)
+                    return ValueType::Int;
+                else if constexpr (std::is_same_v<T, ValueType::DoubleClass>)
+                    return ValueType::Double;
+                else if constexpr (std::is_same_v<T, ValueType::StringClass>)
+                    return ValueType::String;
+                else if constexpr (std::is_same_v<T, ValueType::BoolClass>)
+                    return ValueType::Bool;
+                else if constexpr (std::is_same_v<T, Function>)
+                    return ValueType::Function;
+                else if constexpr (std::is_same_v<T, StructType>)
+                    return ValueType::StructType;
+                else if constexpr (std::is_same_v<T, StructInstance>)
+                    return ValueType::StructInstance;
+                else
+                    return ValueType::Any;
+            },
+                              data);
+        }
+
+        bool isNull() const { return is<ValueType::NullClass>(); }
+        bool isNumeric() const { return is<ValueType::IntClass>() || is<ValueType::DoubleClass>(); }
+
+        ValueType::DoubleClass getNumericValue() const
+        {
+            if (is<ValueType::IntClass>())
+                return static_cast<ValueType::DoubleClass>(as<ValueType::IntClass>());
+            else if (is<ValueType::DoubleClass>())
+                return as<ValueType::DoubleClass>();
+            else
+                throw RuntimeError(u8"getNumericValue: Not a numeric value");
+        }
+
+        FString toString() const
+        {
+            if (is<ValueType::NullClass>()) return FString(u8"null");
+            if (is<ValueType::IntClass>()) return FString(std::to_string(as<ValueType::IntClass>()));
+            if (is<ValueType::DoubleClass>()) return FString(std::format("{}", as<ValueType::DoubleClass>()));
+            if (is<ValueType::StringClass>()) return as<ValueType::StringClass>();
+            if (is<ValueType::BoolClass>()) return as<ValueType::BoolClass>() ? FString(u8"true") : FString(u8"false");
+            if (is<Function>())
+                return FString(std::format("<Function {} at {:p}>",
+                                           as<Function>().id,
+                                           static_cast<const void *>(&as<Function>())));
+            if (is<StructType>())
+                return FString(std::format("<StructType {} at {:p}>",
+                                           as<StructType>().id,
+                                           static_cast<const void *>(&as<StructType>())));
+            if (is<StructInstance>())
+                return FString(std::format("<StructInstance '{}' at {:p}>",
+                                           as<StructInstance>().parentId,
+                                           static_cast<const void *>(&as<StructInstance>())));
+            return FString(u8"<error>");
+        }
+
+    private:
+        static std::string makeTypeErrorMessage(const char *prefix, const char *op,
+                                                const Object &lhs, const Object &rhs)
+        {
+            auto lhs_type = lhs.getTypeInfo().name.toBasicString();
+            auto rhs_type = rhs.getTypeInfo().name.toBasicString();
+            return std::format("{}: {} '{}' {}", prefix, lhs_type, op, rhs_type);
+        }
+
+    public:
+        // math
+        friend Object operator+(const Object &lhs, const Object &rhs)
+        {
+            if (lhs.isNull() || rhs.isNull())
+                throw ValueError(FStringView(makeTypeErrorMessage("Cannot add", "+", lhs, rhs)));
+            if (lhs.isNumeric() && rhs.isNumeric())
+            {
+                bool bothInt = lhs.is<ValueType::IntClass>() && rhs.is<ValueType::IntClass>();
+                auto result = lhs.getNumericValue() + rhs.getNumericValue();
+                if (bothInt && !isNumberExceededIntLimit(result))
+                    return Object(static_cast<ValueType::IntClass>(result));
+                return Object(result);
+            }
+            if (lhs.is<ValueType::StringClass>() && rhs.is<ValueType::StringClass>())
+                return Object(FString(lhs.as<ValueType::StringClass>() + rhs.as<ValueType::StringClass>()));
+            throw ValueError(FStringView(makeTypeErrorMessage("Unsupported operation", "+", lhs, rhs)));
+        }
+
+        friend Object operator-(const Object &lhs, const Object &rhs)
+        {
+            if (lhs.isNull() || rhs.isNull())
+                throw ValueError(FStringView(makeTypeErrorMessage("Cannot subtract", "-", lhs, rhs)));
+            if (lhs.isNumeric() && rhs.isNumeric())
+            {
+                bool bothInt = lhs.is<ValueType::IntClass>() && rhs.is<ValueType::IntClass>();
+                auto result = lhs.getNumericValue() - rhs.getNumericValue();
+                if (bothInt && !isNumberExceededIntLimit(result))
+                    return Object(static_cast<ValueType::IntClass>(result));
+                return Object(result);
+            }
+            throw ValueError(FStringView(makeTypeErrorMessage("Unsupported operation", "-", lhs, rhs)));
+        }
+
+        friend Object operator*(const Object &lhs, const Object &rhs)
+        {
+            if (lhs.isNull() || rhs.isNull())
+                throw ValueError(FStringView(makeTypeErrorMessage("Cannot multiply", "*", lhs, rhs)));
+            if (lhs.isNumeric() && rhs.isNumeric())
+            {
+                bool bothInt = lhs.is<ValueType::IntClass>() && rhs.is<ValueType::IntClass>();
+                auto result = lhs.getNumericValue() * rhs.getNumericValue();
+                if (bothInt && !isNumberExceededIntLimit(result))
+                    return Object(static_cast<ValueType::IntClass>(result));
+                return Object(result);
+            }
+            throw ValueError(FStringView(makeTypeErrorMessage("Unsupported operation", "*", lhs, rhs)));
+        }
+
+        friend Object operator/(const Object &lhs, const Object &rhs)
+        {
+            if (lhs.isNull() || rhs.isNull())
+                throw ValueError(FStringView(makeTypeErrorMessage("Cannot divide", "/", lhs, rhs)));
+            if (lhs.isNumeric() && rhs.isNumeric())
+            {
+                auto rnv = rhs.getNumericValue();
+                if (rnv == 0)
+                    throw ValueError(FStringView(makeTypeErrorMessage("Division by zero", "/", lhs, rhs)));
+                bool bothInt = lhs.is<ValueType::IntClass>() && rhs.is<ValueType::IntClass>();
+                auto result = lhs.getNumericValue() / rnv;
+                if (bothInt && !isNumberExceededIntLimit(result))
+                    return Object(static_cast<ValueType::IntClass>(result));
+                return Object(result);
+            }
+            throw ValueError(FStringView(makeTypeErrorMessage("Unsupported operation", "/", lhs, rhs)));
+        }
+
+        friend Object operator%(const Object &lhs, const Object &rhs)
+        {
+            if (lhs.isNull() || rhs.isNull())
+                throw ValueError(FStringView(makeTypeErrorMessage("Cannot modulo", "%", lhs, rhs)));
+            if (lhs.isNumeric() && rhs.isNumeric())
+            {
+                auto rnv = rhs.getNumericValue();
+                if (rnv == 0)
+                    throw ValueError(FStringView(makeTypeErrorMessage("Modulo by zero", "/", lhs, rhs)));
+                bool bothInt = lhs.is<ValueType::IntClass>() && rhs.is<ValueType::IntClass>();
+                auto result = std::fmod(lhs.getNumericValue(), rnv);
+                if (bothInt && !isNumberExceededIntLimit(result))
+                    return Object(static_cast<ValueType::IntClass>(result));
+                return Object(result);
+            }
+            throw ValueError(FStringView(makeTypeErrorMessage("Unsupported operation", "%", lhs, rhs)));
+        }
+
+        // logic
+        friend Object operator&&(const Object &lhs, const Object &rhs)
+        {
+            if (!lhs.is<ValueType::BoolClass>() || !rhs.is<ValueType::BoolClass>())
+                throw ValueError(FStringView(makeTypeErrorMessage("Logical AND requires bool", "&&", lhs, rhs)));
+            return Object(lhs.as<ValueType::BoolClass>() && rhs.as<ValueType::BoolClass>());
+        }
+
+        friend Object operator||(const Object &lhs, const Object &rhs)
+        {
+            if (!lhs.is<ValueType::BoolClass>() || !rhs.is<ValueType::BoolClass>())
+                throw ValueError(FStringView(makeTypeErrorMessage("Logical OR requires bool", "||", lhs, rhs)));
+            return Object(lhs.as<ValueType::BoolClass>() || rhs.as<ValueType::BoolClass>());
+        }
+
+        friend Object operator!(const Object &v)
+        {
+            if (!v.is<ValueType::BoolClass>())
+                throw ValueError(FStringView(std::format("Logical NOT requires bool: '{}'", v.getTypeInfo().name.toBasicString())));
+            return Object(!v.as<ValueType::BoolClass>());
+        }
+
+        friend Object operator-(const Object &v)
+        {
+            if (v.isNull())
+                throw ValueError(FStringView(u8"Unary minus cannot be applied to null"));
+            if (v.is<ValueType::IntClass>())
+                return Object(-v.as<ValueType::IntClass>());
+            if (v.is<ValueType::DoubleClass>())
+                return Object(-v.as<ValueType::DoubleClass>());
+            throw ValueError(FStringView(std::format("Unary minus requires int or double: '{}'", v.getTypeInfo().name.toBasicString())));
+        }
+
+        friend Object operator~(const Object &v)
+        {
+            if (!v.is<ValueType::IntClass>())
+                throw ValueError(FStringView(std::format("Bitwise NOT requires int: '{}'", v.getTypeInfo().name.toBasicString())));
+            return Object(~v.as<ValueType::IntClass>());
+        }
+
+        // comparison
+        friend bool operator==(const Object &lhs, const Object &rhs) { return lhs.data == rhs.data; }
+        friend bool operator!=(const Object &lhs, const Object &rhs) { return !(lhs == rhs); }
+        friend bool operator<(const Object &lhs, const Object &rhs)
+        {
+            if (lhs.isNumeric() && rhs.isNumeric()) return lhs.getNumericValue() < rhs.getNumericValue();
+            if (lhs.is<ValueType::StringClass>() && rhs.is<ValueType::StringClass>())
+                return lhs.as<ValueType::StringClass>() < rhs.as<ValueType::StringClass>();
+            throw ValueError(FStringView(makeTypeErrorMessage("Unsupported comparison", "<", lhs, rhs)));
+        }
+        friend bool operator<=(const Object &lhs, const Object &rhs) { return lhs == rhs || lhs < rhs; }
+        friend bool operator>(const Object &lhs, const Object &rhs)
+        {
+            if (lhs.isNumeric() && rhs.isNumeric()) return lhs.getNumericValue() > rhs.getNumericValue();
+            if (lhs.is<ValueType::StringClass>() && rhs.is<ValueType::StringClass>())
+                return lhs.as<ValueType::StringClass>() > rhs.as<ValueType::StringClass>();
+            throw ValueError(FStringView(makeTypeErrorMessage("Unsupported comparison", ">", lhs, rhs)));
+        }
+        friend bool operator>=(const Object &lhs, const Object &rhs) { return lhs == rhs || lhs > rhs; }
+
+        // bitwise
+        friend Object bit_and(const Object &lhs, const Object &rhs)
+        {
+            if (!lhs.is<ValueType::IntClass>() || !rhs.is<ValueType::IntClass>())
+                throw ValueError(FStringView(makeTypeErrorMessage("Bitwise AND requires int", "&", lhs, rhs)));
+            return Object(lhs.as<ValueType::IntClass>() & rhs.as<ValueType::IntClass>());
+        }
+
+        friend Object bit_or(const Object &lhs, const Object &rhs)
+        {
+            if (!lhs.is<ValueType::IntClass>() || !rhs.is<ValueType::IntClass>())
+                throw ValueError(FStringView(makeTypeErrorMessage("Bitwise OR requires int", "|", lhs, rhs)));
+            return Object(lhs.as<ValueType::IntClass>() | rhs.as<ValueType::IntClass>());
+        }
+
+        friend Object bit_xor(const Object &lhs, const Object &rhs)
+        {
+            if (!lhs.is<ValueType::IntClass>() || !rhs.is<ValueType::IntClass>())
+                throw ValueError(FStringView(makeTypeErrorMessage("Bitwise XOR requires int", "^", lhs, rhs)));
+            return Object(lhs.as<ValueType::IntClass>() ^ rhs.as<ValueType::IntClass>());
+        }
+
+        friend Object bit_not(const Object &v)
+        {
+            if (!v.is<ValueType::IntClass>())
+                throw ValueError(FStringView(std::format("Bitwise NOT requires int: '{}'", v.getTypeInfo().name.toBasicString())));
+            return Object(~v.as<ValueType::IntClass>());
+        }
+
+        friend Object shift_left(const Object &lhs, const Object &rhs)
+        {
+            if (!lhs.is<ValueType::IntClass>() || !rhs.is<ValueType::IntClass>())
+                throw ValueError(FStringView(makeTypeErrorMessage("Shift left requires int", "<<", lhs, rhs)));
+            return Object(lhs.as<ValueType::IntClass>() << rhs.as<ValueType::IntClass>());
+        }
+
+        friend Object shift_right(const Object &lhs, const Object &rhs)
+        {
+            if (!lhs.is<ValueType::IntClass>() || !rhs.is<ValueType::IntClass>())
+                throw ValueError(FStringView(makeTypeErrorMessage("Shift right requires int", ">>", lhs, rhs)));
+            return Object(lhs.as<ValueType::IntClass>() >> rhs.as<ValueType::IntClass>());
+        }
+
+        friend Object power(const Object &base, const Object &exp)
+        {
+            if (base.isNull() || exp.isNull())
+                throw ValueError(FStringView(makeTypeErrorMessage("Cannot exponentiate", "**", base, exp)));
+            if (base.isNumeric() && exp.isNumeric())
+            {
+                bool bothInt = base.is<ValueType::IntClass>() && exp.is<ValueType::IntClass>();
+                auto result = std::pow(base.getNumericValue(), exp.getNumericValue());
+                if (bothInt && !isNumberExceededIntLimit(result))
+                    return Object(static_cast<ValueType::IntClass>(result));
+                return Object(result);
+            }
+            throw ValueError(FStringView(makeTypeErrorMessage("Unsupported operation", "**", base, exp)));
+        }
+    };
+
+    using ObjectPtr = std::shared_ptr<Object>;
+    using RvObject = ObjectPtr;
+
+    struct VariableSlot
+    {
+        FString name;
+        ObjectPtr value;
+        TypeInfo declaredType;
+        AccessModifier am;
+
+        bool isRef = false;
+        std::shared_ptr<VariableSlot> refTarget;
+    };
+
+    struct LvObject
+    {
+        std::shared_ptr<VariableSlot> slot;
+
+        const ObjectPtr& get() const
+        {
+            auto s = resolve(slot);
+            return s->value;
+        }
+
+        void set(const ObjectPtr& v)
+        {
+            auto s = resolve(slot);
+            if (s->declaredType != ValueType::Any && s->declaredType != v->getTypeInfo())
+            {
+                throw RuntimeError(
+                    FStringView(
+                        std::format("Variable `{}` expects type `{}`, but got '{}'",
+                            s->name.toBasicString(),
+                            s->declaredType.toString().toBasicString(),
+                            v->getTypeInfo().toString().toBasicString())
+                    )
+                );
+            }
+            if (isAccessConst(s->am))
+            {
+                throw RuntimeError(FStringView(
+                    std::format("Variable `{}` is immutable", s->name.toBasicString())
+                ));
+            }
+            s->value = v;
+        }
+
+        FString name() const { return resolve(slot)->name; }
+        TypeInfo declaredType() const { return resolve(slot)->declaredType; }
+        AccessModifier access() const { return resolve(slot)->am; }
+
+    private:
+        std::shared_ptr<VariableSlot> resolve(std::shared_ptr<VariableSlot> s) const
+        {
+            while (s->isRef) s = s->refTarget;
+            return s;
+        }
+    };
+
+
+} // namespace Fig

src/Value/valueError.hpp

@@ -0,0 +1,17 @@
+#pragma once
+
+#include <Error/error.hpp>
+
+namespace Fig
+{
+    class ValueError : public UnaddressableError
+    {
+    public:
+        using UnaddressableError::UnaddressableError;
+        virtual FString toString() const override
+        {
+            std::string msg = std::format("[ValueError] {} in [{}] {}", std::string(this->message.begin(), this->message.end()), this->src_loc.file_name(), this->src_loc.function_name());
+            return FString(msg);
+        }
+    };
+};