xo-expression: + environment implementation

include/xo/expression/Environment.hpp

@@ -0,0 +1,23 @@
+/* file Environment.hpp
+ *
+ * author: Roland Conybeare, Jun 2024
+ */
+
+#pragma once
+
+#include "xo/refcnt/Refcounted.hpp"
+#include "Variable.hpp"
+
+namespace xo {
+    namespace ast {
+        class Environment : public ref::Refcount {
+        public:
+            /** lookup variable-expression @p vname in this environment
+             **/
+            virtual ref::brw<Variable> lookup_var(const std::string & vname) const = 0;
+        };
+    } /*namespace ast*/
+} /*namespace xo*/
+
+
+/* end Environment.hpp */