xo-gc: + CollectorTypeRegistry for streamlined init

xo-object2/src/object2/CMakeLists.txt

@@ -19,6 +19,7 @@ set(SELF_SRCS
     DFloat.cpp
     DInteger.cpp
     DString.cpp
+    init_object2.cpp
     object2_register_types.cpp
     object2_register_facets.cpp
     )
@@ -27,4 +28,5 @@ xo_add_shared_library4(${SELF_LIB} ${PROJECT_NAME}Targets ${PROJECT_VERSION} 1 $
 # note: deps here must also appear in cmake/xo_object2Config.cmake.in
 xo_dependency(${SELF_LIB} xo_gc)
 xo_dependency(${SELF_LIB} xo_printable2)
+xo_dependency(${SELF_LIB} subsys)
 xo_dependency(${SELF_LIB} indentlog)

xo-object2/src/object2/init_object2.cpp

@@ -0,0 +1,39 @@
+/** @file init_object2.cpp
+*
+ *  @author Roland Conybeare, Jan 2026
+ **/
+
+#include "init_object2.hpp"
+#include "object2_register_facets.hpp"
+#include "object2_register_types.hpp"
+#include <xo/gc/CollectorTypeRegistry.hpp>
+
+namespace xo {
+    using xo::scm::object2_register_facets;
+    using xo::scm::object2_register_types;
+    using xo::mm::CollectorTypeRegistry;
+
+    void
+    InitSubsys<S_object2_tag>::init()
+        {
+            object2_register_facets();
+
+            CollectorTypeRegistry::instance().register_types(&object2_register_types);
+        }
+
+    InitEvidence
+    InitSubsys<S_object2_tag>::require()
+        {
+            InitEvidence retval;
+
+            /* direct subsystem deps for xo-object2/ */
+            // retval ^= InitSubsys<S_somedep_tag>::require();
+
+            /* xo-expression2/'s own initialization code */
+            retval ^= Subsystem::provide<S_object2_tag>("object2", &init);
+
+            return retval;
+        }
+} /*namespace xo*/
+
+/* end init_object2.cpp */