xo-gc: + CollectorTypeRegistry for streamlined init

xo-expression2/src/expression2/init_expression2.cpp

@@ -0,0 +1,41 @@
+/** @file init_expression2.cpp
+*
+ *  @author Roland Conybeare, Jan 2026
+ **/
+
+#include "init_expression2.hpp"
+#include "expression2_register_facets.hpp"
+#include "expression2_register_types.hpp"
+
+#include <xo/object2/init_object2.hpp>
+#include <xo/gc/CollectorTypeRegistry.hpp>
+
+namespace xo {
+    using xo::scm::expression2_register_facets;
+    using xo::scm::expression2_register_types;
+    using xo::mm::CollectorTypeRegistry;
+
+    void
+    InitSubsys<S_expression2_tag>::init()
+        {
+            expression2_register_facets();
+
+            CollectorTypeRegistry::instance().register_types(&expression2_register_types);
+        }
+
+    InitEvidence
+    InitSubsys<S_expression2_tag>::require()
+        {
+            InitEvidence retval;
+
+            /* direct subsystem deps for xo-object2/ */
+            retval ^= InitSubsys<S_object2_tag>::require();
+
+            /* xo-expression2/'s own initialization code */
+            retval ^= Subsystem::provide<S_expression2_tag>("expression2", &init);
+
+            return retval;
+        }
+} /*namespace xo*/
+
+/* end init_expression2.cpp */