[Feat] 支持运算符重载！详见文档或 Library/lang/lang.fig中的定义。通过 impl Operation for xxx实现重载

[Impl] 函数参数指定现在也接受一个 exp，逐渐改动其他中...

src/Evaluator/Core/EvalUnary.cpp

@@ -1,3 +1,4 @@
+#include "Evaluator/Value/value.hpp"
 #include <Evaluator/Value/LvObject.hpp>
 #include <Evaluator/evaluator.hpp>
 #include <Evaluator/evaluator_error.hpp>
@@ -10,16 +11,31 @@ namespace Fig
         Operator op = un->op;
         Ast::Expression exp = un->exp;
         ObjectPtr value = eval(exp, ctx);
+
+        const auto &tryInvokeOverloadFn = [ctx, op](const ObjectPtr &rhs, const std::function<ObjectPtr()> &rollback) {
+            if (rhs->is<StructInstance>())
+            {
+                // 运算符重载
+                const TypeInfo &type = actualType(rhs);
+                if (ctx->hasOperatorImplemented(type, op))
+                {
+                    const auto &fnOpt = ctx->getUnaryOperatorFn(type, op);
+                    return (*fnOpt)(rhs);
+                }
+            }
+            return rollback();
+        };
+
         switch (op)
         {
             case Operator::Not: {
-                return std::make_shared<Object>(!(*value));
+                return tryInvokeOverloadFn(value, [value]() { return std::make_shared<Object>(!(*value)); });
             }
             case Operator::Subtract: {
-                return std::make_shared<Object>(-(*value));
+                return tryInvokeOverloadFn(value, [value]() { return std::make_shared<Object>(-(*value)); });
             }
             case Operator::BitNot: {
-                return std::make_shared<Object>(bit_not((*value)));
+                return tryInvokeOverloadFn(value, [value]() { return std::make_shared<Object>(bit_not(*value)); });
             }
             default: {
                 throw EvaluatorError(u8"UnsupportedOpError",
@@ -28,4 +44,4 @@ namespace Fig
             }
         }
     }
-};
+}; // namespace Fig