xo-expression2: + Expression facet

include/xo/expression2/DConstant.hpp

@@ -0,0 +1,37 @@
+/** @file DConstant.hpp
+ *
+ *  @author Roland Conybeare, Jan 2026
+ **/
+
+#include <xo/reflect/TypeDescr.hpp>
+
+namespace xo {
+    namespace scm {
+        /** @class DConstant
+         *  @brief Schematika expression respresenting a literal constant
+         **/
+        struct DConstant {
+        public:
+            using TypeDescr = xo::reflect::TypeDescr;
+
+        public:
+            DConstant(TypeDescr td, void * value);
+
+            TypeDescr value_td() const { return value_td; }
+
+            TypeRef typeref() const noexcept;
+            TypeDescr valuetype() const noexcept;
+            void assign_valuetype(TypeDescr td) noexcept;
+
+        private:
+            /** type for value of this expression **/
+            TypeRef type_ref_;
+            /** type description for destination *value_ **/
+            TypeDescr valuetype_;
+            /** literal value **/
+            void * value_;
+        };
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/* end DConstant.hpp */