[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/Ast/Statements/FunctionDefSt.hpp

@@ -0,0 +1,45 @@
+#pragma once
+
+#include <Ast/astBase.hpp>
+#include <Ast/functionParameters.hpp>
+
+#include <Value/value.hpp>
+
+namespace Fig::Ast
+{
+    /*
+        func greet(greeting, name:String, age:Int, split:String=":") -> Null
+        {
+            io.println("{}, {}{}{}", greeting, name, split, age);
+        }
+
+        `greeting`, `name`, `age` -> positional parameters
+        `split`                   -> default parameter
+        */
+
+    class FunctionDefSt final : public StatementAst // for definition
+    {
+    public:
+        FString name;
+        FunctionParameters paras;
+        bool isPublic;
+        FString retType;
+        BlockStatement body;
+        FunctionDefSt() :
+            retType(ValueType::Null.name)
+        {
+            type = AstType::FunctionDefSt;
+        }
+        FunctionDefSt(FString _name, FunctionParameters _paras, bool _isPublic, FString _retType, BlockStatement _body)
+        {
+            type = AstType::FunctionDefSt;
+
+            name = std::move(_name);
+            paras = std::move(_paras);
+            isPublic = _isPublic;
+            retType = std::move(_retType);
+            body = std::move(_body);
+        }
+    };
+    using FunctionDef = std::shared_ptr<FunctionDefSt>;
+}; // namespace Fig