+ xo-interpreter2 scaffold for constant expression [WIP]

src/expression2/CMakeLists.txt

@@ -2,6 +2,7 @@
 
 set(SELF_LIB xo_expression2)
 set(SELF_SRCS
+    DConstant.cpp
     TypeRef.cpp
     #IExpression_Any.cpp
     expression2_register_facets.cpp
@@ -11,6 +12,7 @@ xo_add_shared_library4(${SELF_LIB} ${PROJECT_NAME}Targets ${PROJECT_VERSION} 1 $
 # note: deps here must also appear in cmake/xo_expression2Config.cmake.in
 xo_dependency(${SELF_LIB} xo_gc)
 xo_dependency(${SELF_LIB} reflect)
+xo_dependency(${SELF_LIB} xo_object2)
 xo_dependency(${SELF_LIB} xo_printable2)
 xo_dependency(${SELF_LIB} xo_flatstring)
 xo_dependency(${SELF_LIB} indentlog)

src/expression2/DConstant.cpp

@@ -0,0 +1,53 @@
+/** @file DConstant.cpp
+ *
+ *  @author Roland Conybeare, Jan 2026
+ **/
+
+#include "DConstant.hpp"
+#include "TypeDescr.hpp"
+#include <xo/object2/DFloat.hpp>
+#include <xo/object2/DInteger.hpp>
+#include <xo/reflect/Reflect.hpp>
+#include <xo/reflectutil/typeseq.hpp>
+
+namespace xo {
+    using xo::scm::DFloat;
+    using xo::scm::DInteger;
+    using xo::reflect::Reflect;
+    using xo::reflect::TypeDescr;
+    using xo::reflect::typeseq;
+
+    namespace scm {
+        DConstant::DConstant(obj<AGCObject> value) noexcept
+            :
+            //typeref_{TypeRef::resolved(td)},
+              value_{value}
+        {
+            // todo: use ObjectConverter here
+
+            auto tseq = value_._typeseq();
+
+            TypeDescr td = this->_lookup_td(tseq);
+
+            if (td) {
+                typeref_ = TypeRef::resolved(td);
+            }
+        }
+
+        TypeDescr
+        DConstant::_lookup_td(typeseq tseq)
+        {
+            if (tseq == typeseq::id<DFloat>()) {
+                /* double */
+                return Reflect::require<DFloat::value_type>();
+            } else if (tseq == typeseq::id<DInteger>()) {
+                /* long */
+                return Reflect::require<DInteger::value_type>();
+            }
+
+            return nullptr;
+        }
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/* end DConstant.cpp */

src/expression2/TypeRef.cpp

@@ -11,6 +11,15 @@ namespace xo {
                 : id_{id}, td_{td}
         {}
 
+        TypeRef
+        TypeRef::resolved(TypeDescr td)
+        {
+            assert(td);
+
+            type_var null;
+            return TypeRef(null, td);
+        }
+
         TypeRef
         TypeRef::dwim(prefix_type prefix, TypeDescr td)
         {
@@ -18,8 +27,7 @@ namespace xo {
                 /* type already resolved
                  *  -> we don't need a type variable name
                  */
-                type_var null;
-                return TypeRef(null, td);
+                return TypeRef::resolved(td);
             } else {
                 /* type is not resolved yet.
                  *  -> give it a unique name,
@@ -49,7 +57,7 @@ namespace xo {
         }
 
         bool
-        TypeRef::is_concrete() const noexcept
+        TypeRef::is_resolved() const noexcept
         {
             return (td_ != nullptr);
         }