Set variable declaration context

include/elna/gcc/elna-generic.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include "elna/source/ast.h"
+#include "elna/gcc/elna-tree.h"
 
 #include "config.h"
 #include "system.h"
@@ -21,8 +22,12 @@ namespace gcc
         tree current_expression{ NULL_TREE };
         std::unordered_map<std::string, tree> symbol_map;
         tree main_fndecl{ NULL_TREE };
+        tree_chain variable_chain;
 
-        tree build_label_decl (const char *name, location_t loc);
+        tree build_label_decl(const char *name, location_t loc);
+
+        void enter_scope();
+        tree_symbol_mapping leave_scope();
 
     public:
         void visit(source::program *program) override;

include/elna/gcc/elna-tree.h

@@ -23,5 +23,36 @@ namespace gcc
 {
     void init_ttree();
     bool is_string_type(tree type);
+
+    class tree_chain_base
+    {
+    protected:
+        tree first{};
+        tree last{};
+
+    public:
+        tree head();
+        void append(tree t);
+
+    protected:
+        virtual void chain(tree t) = 0;
+    };
+
+    class tree_chain final : public tree_chain_base
+    {
+        void chain(tree t) override;
+    };
+
+    class tree_symbol_mapping final
+    {
+        tree m_bind_expression;
+        tree m_block;
+
+    public:
+        tree_symbol_mapping(tree bind_expression, tree block);
+
+        tree bind_expression();
+        tree block();
+    };
 }
 }