xo-object2: GCObjectConversion for double (via DFloat)

cmake/xo_object2Config.cmake.in

@@ -1,6 +1,7 @@
 @PACKAGE_INIT@
 
 include(CMakeFindDependencyMacro)
+find_dependency(reflect)
 find_dependency(xo_gc)
 find_dependency(xo_printable2)
 find_dependency(subsys)

include/xo/object2/number/GCObjectConversion_DFloat.hpp

@@ -0,0 +1,29 @@
+/** @file GCObjectConversion_DFloat.hpp
+ *
+ *  @author Roland Conybeare, Jan 2026
+ **/
+
+#pragma once
+
+#include "DFloat.hpp"
+#include "number/IGCObject_DFloat.hpp"
+#include <xo/gc/GCObjectConversion.hpp>
+
+namespace xo {
+    namespace scm {
+
+        template <>
+        struct GCObjectConversion<double> {
+            static_assert(std::is_same_v<double, DFloat::value_type>);
+
+            using AGCObject = xo::mm::AGCObject;
+            using AAllocator = xo::mm::AAllocator;
+
+            static obj<AGCObject> to_gco(obj<AAllocator> mm, const double & x);
+            static double from_gco(obj<AAllocator> mm, obj<AGCObject> gco);
+        };
+
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/* end GCObjectConversion_DFloat.hpp */

src/object2/CMakeLists.txt

@@ -2,6 +2,10 @@
 
 set(SELF_LIB xo_object2)
 set(SELF_SRCS
+    init_object2.cpp
+    object2_register_types.cpp
+    object2_register_facets.cpp
+    GCObjectConversion_DFloat.cpp
     IGCObject_DArray.cpp
     IGCObject_DFloat.cpp
     IGCObject_DBoolean.cpp
@@ -22,13 +26,11 @@ set(SELF_SRCS
     DInteger.cpp
     DBoolean.cpp
     DString.cpp
-    init_object2.cpp
-    object2_register_types.cpp
-    object2_register_facets.cpp
     )
 
 xo_add_shared_library4(${SELF_LIB} ${PROJECT_NAME}Targets ${PROJECT_VERSION} 1 ${SELF_SRCS})
 # note: deps here must also appear in cmake/xo_object2Config.cmake.in
+xo_dependency(${SELF_LIB} reflect)
 xo_dependency(${SELF_LIB} xo_gc)
 xo_dependency(${SELF_LIB} xo_printable2)
 xo_dependency(${SELF_LIB} subsys)

src/object2/GCObjectConversion_DFloat.cpp

@@ -0,0 +1,41 @@
+/** @file GCObjectConversion_DFloat.cpp
+ *
+ *  @author Roland Conybeare, Jan 2026
+ **/
+
+#include "number/GCObjectConversion_DFloat.hpp"
+#include <xo/indentlog/print/tag.hpp>
+
+namespace xo {
+    using xo::mm::AGCObject;
+
+    namespace scm {
+
+        obj<AGCObject>
+        GCObjectConversion<double>::to_gco(obj<AAllocator> mm,
+                                           const double & x)
+        {
+            return DFloat::box<AGCObject>(mm, x);
+        }
+
+        double
+        GCObjectConversion<double>::from_gco(obj<AAllocator> mm,
+                                             obj<AGCObject> gco)
+        {
+            (void)mm;
+
+            auto float_obj = obj<AGCObject,DFloat>::from(gco);
+
+            if (!float_obj) {
+                throw std::runtime_error
+                    (tostr("Object obj found where Float expected",
+                           xtag("obj", gco)));
+            }
+
+            return float_obj.data()->value();
+        }
+
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/* end GCObjectConversion_DFloat.cpp */