[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/ExpressionStmt.hpp

@@ -0,0 +1,21 @@
+#pragma once
+
+#include <Ast/astBase.hpp>
+
+namespace Fig::Ast
+{
+    class ExpressionStmtAst final : public StatementAst
+    {
+    public:
+        Expression exp;
+        ExpressionStmtAst()
+        {
+            type = AstType::ExpressionStmt;
+        }
+        ExpressionStmtAst(Expression _exp) : exp(std::move(_exp))
+        {
+            type = AstType::ExpressionStmt;
+        }
+    };
+    using ExpressionStmt = std::shared_ptr<ExpressionStmtAst>;
+}