xo-expression2: + IExpression_DConstant

include/xo/expression2/DConstant.hpp

@@ -3,6 +3,8 @@
  *  @author Roland Conybeare, Jan 2026
  **/
 
+#pragma once
+
 #include "TypeRef.hpp"
 #include "exprtype.hpp"
 #include <xo/reflect/TaggedPtr.hpp>

include/xo/expression2/IExpression_DConstant.hpp

@@ -0,0 +1,63 @@
+/** @file IExpression_DConstant.hpp
+ *
+ *  Generated automagically from ingredients:
+ *  1. code generator:
+ *       [/home/roland/proj/xo-umbrella2-claude1/xo-facet/codegen/genfacet]
+ *     arguments:
+ *       --input [idl/IExpression_DConstant.json5]
+ *  2. jinja2 template for abstract facet .hpp file:
+ *       [iface_facet_any.hpp.j2]
+ *  3. idl for facet methods
+ *       [idl/IExpression_DConstant.json5]
+ **/
+
+#pragma once
+
+#include "Expression.hpp"
+#include "DConstant.hpp"
+
+namespace xo { namespace scm { class IExpression_DConstant; } }
+
+namespace xo {
+    namespace facet {
+        template <>
+        struct FacetImplementation<xo::scm::AExpression,
+                                   xo::scm::DConstant>
+        {
+            using ImplType = xo::scm::IExpression_Xfer
+              <xo::scm::DConstant,
+               xo::scm::IExpression_DConstant>;
+        };
+    }
+}
+
+namespace xo {
+    namespace scm {
+        /** @class IExpression_DConstant
+         **/
+        class IExpression_DConstant {
+        public:
+            /** @defgroup scm-expression-dconstant-type-traits **/
+            ///@{
+            using TypeDescr = xo::scm::AExpression::TypeDescr;
+            ///@}
+            /** @defgroup scm-expression-dconstant-methods **/
+            ///@{
+            // const methods
+            /** expression type (constant | apply | ..) **/
+            static exprtype extype(const DConstant & self) noexcept;
+            /** placeholder for type giving possible values for this expression **/
+            static TypeRef typeref(const DConstant & self) noexcept;
+            /** type giving possible values for this expression. Maybe null before typecheck **/
+            static TypeDescr valuetype(const DConstant & self) noexcept;
+
+            // non-const methods
+            /** assing to valuetype member. Useful when scaffolding expressions **/
+            static void assign_valuetype(DConstant & self, TypeDescr td) noexcept;
+            ///@}
+        };
+
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/* end */