refactor(dev): 移动头文件位置

include/sem/Sema.h

@@ -0,0 +1,30 @@
+// 基于语法树的语义检查与名称绑定。
+#pragma once
+
+#include <unordered_map>
+
+#include "SysYParser.h"
+
+class SemanticContext {
+ public:
+  void BindVarUse(SysYParser::PrimaryContext* use,
+                  SysYParser::VarDeclContext* decl) {
+    var_uses_[use] = decl;
+  }
+
+  SysYParser::VarDeclContext* ResolveVarUse(
+      const SysYParser::PrimaryContext* use) const {
+    auto it = var_uses_.find(use);
+    return it == var_uses_.end() ? nullptr : it->second;
+  }
+
+ private:
+  std::unordered_map<const SysYParser::PrimaryContext*,
+                     SysYParser::VarDeclContext*>
+      var_uses_;
+};
+
+// 目前仅检查：
+// - 变量先声明后使用
+// - 局部变量不允许重复定义
+SemanticContext RunSema(SysYParser::CompUnitContext& comp_unit);

include/sem/SymbolTable.h

@@ -0,0 +1,17 @@
+// 极简符号表：记录局部变量定义点。
+#pragma once
+
+#include <string>
+#include <unordered_map>
+
+#include "SysYParser.h"
+
+class SymbolTable {
+ public:
+  void Add(const std::string& name, SysYParser::VarDeclContext* decl);
+  bool Contains(const std::string& name) const;
+  SysYParser::VarDeclContext* Lookup(const std::string& name) const;
+
+ private:
+  std::unordered_map<std::string, SysYParser::VarDeclContext*> table_;
+};