xo-reader2 xo-expresion2: work on define-expressions [WIP]

xo-expression2/include/xo/expression2/DGlobalSymtab.hpp

@@ -0,0 +1,39 @@
+/** @file DGlobalSymtab.hpp
+*
+ *  @author Roland Conybeare, Jan 2026
+ **/
+
+#pragma once
+
+#include "Binding.hpp"
+
+namespace xo {
+    namespace scm {
+        class DUniqueString;
+
+        /** @class DGlobalSymtab
+         *  @brief symbol table for toplevel environment
+         **/
+        struct DGlobalSymtab {
+        public:
+
+
+        public:
+            /** @defgroup xo-expression2-symboltable-facet symboltable facet**/
+            ///@{
+
+            /** true for global symbol table **/
+            bool is_global_symtab() const noexcept { return true; }
+
+            /** lookup binding for variable @p sym **/
+            Binding lookup_binding(const DUniqueString * sym) const noexcept;
+
+            ///@}
+
+        private:
+        };
+
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/* end DGlobalSymtab.hpp */