From e87073f9141a7e6471286327ef2e448a9a1a8b08 Mon Sep 17 00:00:00 2001
From: Roland Conybeare <rconybeare@gmail.com>
Date: Mon, 16 Feb 2026 09:31:49 -0500
Subject: [PATCH] xo-alloc2: register DArena facet + subsystem init

---
 .../xo/alloc2/alloc2_register_facets.hpp      | 15 ++++++++
 xo-alloc2/include/xo/alloc2/init_alloc2.hpp   | 23 ++++++++++++
 xo-alloc2/src/alloc2/CMakeLists.txt           | 10 ++----
 .../src/alloc2/alloc2_register_facets.cpp     | 33 +++++++++++++++++
 xo-alloc2/src/alloc2/init_alloc2.cpp          | 36 +++++++++++++++++++
 xo-object2/src/object2/init_object2.cpp       |  3 +-
 .../src/object2/object2_register_facets.cpp   | 31 +++++++++-------
 7 files changed, 131 insertions(+), 20 deletions(-)
 create mode 100644 xo-alloc2/include/xo/alloc2/alloc2_register_facets.hpp
 create mode 100644 xo-alloc2/include/xo/alloc2/init_alloc2.hpp
 create mode 100644 xo-alloc2/src/alloc2/alloc2_register_facets.cpp
 create mode 100644 xo-alloc2/src/alloc2/init_alloc2.cpp

diff --git a/xo-alloc2/include/xo/alloc2/alloc2_register_facets.hpp b/xo-alloc2/include/xo/alloc2/alloc2_register_facets.hpp
new file mode 100644
index 00000000..a53248a2
--- /dev/null
+++ b/xo-alloc2/include/xo/alloc2/alloc2_register_facets.hpp
@@ -0,0 +1,15 @@
+/** @file alloc2_register_facets.hpp
+ *
+ *  @author Roland Conybeare, Feb 2026
+ **/
+
+#pragma once
+
+namespace xo {
+    namespace mm {
+        /** Register alloc2 (facet,impl) combinations with Facet Registry **/
+        bool alloc2_register_facets();
+    }
+}
+
+/* end alloc2_register_facets.hpp */
diff --git a/xo-alloc2/include/xo/alloc2/init_alloc2.hpp b/xo-alloc2/include/xo/alloc2/init_alloc2.hpp
new file mode 100644
index 00000000..c13160b8
--- /dev/null
+++ b/xo-alloc2/include/xo/alloc2/init_alloc2.hpp
@@ -0,0 +1,23 @@
+/** @file init_alloc2.hpp
+ *
+ *  @author Roland Conybeare, Feb 2026
+ **/
+
+#pragma once
+
+#include <xo/subsys/Subsystem.hpp>
+
+namespace xo {
+    /* tag to represent the xo-alloc2/ subsystem within ordered initialization */
+    enum S_alloc2_tag {};
+
+    template <>
+    struct InitSubsys<S_alloc2_tag> {
+        static void init();
+        static InitEvidence require();
+    };
+
+
+} /*namespace xo*/
+
+/* end init_alloc2.hpp */
diff --git a/xo-alloc2/src/alloc2/CMakeLists.txt b/xo-alloc2/src/alloc2/CMakeLists.txt
index 7cebc7ae..29890c5f 100644
--- a/xo-alloc2/src/alloc2/CMakeLists.txt
+++ b/xo-alloc2/src/alloc2/CMakeLists.txt
@@ -3,26 +3,22 @@
 set(SELF_LIB xo_alloc2)
 set(SELF_SRCS
 
-#    AllocError.cpp
-#    AllocInfo.cpp
-#    cmpresult.cpp
+    init_alloc2.cpp
+    alloc2_register_facets.cpp
 
     AAllocator.cpp
-#    ArenaConfig.cpp
-#    DArena.cpp
     IAllocator_Any.cpp
     IAllocator_DArena.cpp
 
     IAllocIterator_Any.cpp
-#    DArenaIterator.cpp
     IAllocIterator_DArenaIterator.cpp
 
     IResourceVisitor_Any.cpp
-
     )
 
 xo_add_shared_library4(${SELF_LIB} ${PROJECT_NAME}Targets ${PROJECT_VERSION} 1 ${SELF_SRCS})
 # note: deps here must also appear in cmake/xo_alloc2Config.cmake.in
 xo_dependency(${SELF_LIB} xo_arena)
 xo_dependency(${SELF_LIB} xo_facet)
+xo_dependency(${SELF_LIB} subsys)
 xo_dependency(${SELF_LIB} indentlog)
diff --git a/xo-alloc2/src/alloc2/alloc2_register_facets.cpp b/xo-alloc2/src/alloc2/alloc2_register_facets.cpp
new file mode 100644
index 00000000..e03afde0
--- /dev/null
+++ b/xo-alloc2/src/alloc2/alloc2_register_facets.cpp
@@ -0,0 +1,33 @@
+/** @file alloc2_register_facets.cpp
+ *
+ * @author Roland Conybeare, Feb 2026
+ **/
+
+#include "alloc2_register_facets.hpp"
+#include <xo/alloc2/Arena.hpp>
+#include <xo/facet/FacetRegistry.hpp>
+#include <xo/indentlog/scope.hpp>
+
+namespace xo {
+    using xo::facet::FacetRegistry;
+    //using xo::facet::TypeRegistry;
+    using xo::reflect::typeseq;
+
+    namespace mm {
+
+        bool
+        alloc2_register_facets()
+        {
+            scope log(XO_DEBUG(true));
+
+            FacetRegistry::register_impl<AAllocator, DArena>();
+
+            log && log(xtag("DArena.tseq", typeseq::id<DArena>()));
+
+            return true;
+        }
+
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/* end alloc2_register_facets.cpp */
diff --git a/xo-alloc2/src/alloc2/init_alloc2.cpp b/xo-alloc2/src/alloc2/init_alloc2.cpp
new file mode 100644
index 00000000..d3fb73fa
--- /dev/null
+++ b/xo-alloc2/src/alloc2/init_alloc2.cpp
@@ -0,0 +1,36 @@
+/** @file init_alloc2.cpp
+ *
+ *  @author Roland Conybeare, Feb 2026
+ **/
+
+#include "init_alloc2.hpp"
+#include "alloc2_register_facets.hpp"
+
+namespace xo {
+    using xo::mm::alloc2_register_facets;
+    // using xo::mm::alloc2_register_types;
+    // using xo::mm::CollectorTypeRegistry;
+
+    void
+    InitSubsys<S_alloc2_tag>::init()
+    {
+        alloc2_register_facets();
+    }
+
+    InitEvidence
+    InitSubsys<S_alloc2_tag>::require()
+    {
+        InitEvidence retval;
+
+        /* direct subsystem deps for xo-alloc2/ (if/when) */
+        //retval ^= InitSubsys<S_foo_tag>>::require();
+
+        /* xo-alloc2/'s own initialization code */
+        retval ^= Subsystem::provide<S_alloc2_tag>("alloc2", &init);
+
+        return retval;
+    }
+
+} /*namespace xo*/
+
+/* end init_alloc2.cpp */
diff --git a/xo-object2/src/object2/init_object2.cpp b/xo-object2/src/object2/init_object2.cpp
index 0f804fe0..bcf7608c 100644
--- a/xo-object2/src/object2/init_object2.cpp
+++ b/xo-object2/src/object2/init_object2.cpp
@@ -7,6 +7,7 @@
 #include "object2_register_facets.hpp"
 #include "object2_register_types.hpp"
 #include <xo/gc/CollectorTypeRegistry.hpp>
+#include <xo/alloc2/init_alloc2.hpp>
 
 namespace xo {
     using xo::scm::object2_register_facets;
@@ -27,7 +28,7 @@ namespace xo {
             InitEvidence retval;
 
             /* direct subsystem deps for xo-object2/ */
-            // retval ^= InitSubsys<S_somedep_tag>::require();
+            retval ^= InitSubsys<S_alloc2_tag>::require();
 
             /* xo-expression2/'s own initialization code */
             retval ^= Subsystem::provide<S_object2_tag>("object2", &init);
diff --git a/xo-object2/src/object2/object2_register_facets.cpp b/xo-object2/src/object2/object2_register_facets.cpp
index c6358474..01d6ef04 100644
--- a/xo-object2/src/object2/object2_register_facets.cpp
+++ b/xo-object2/src/object2/object2_register_facets.cpp
@@ -6,22 +6,29 @@
 #include "object2_register_facets.hpp"
 #include "RuntimeError.hpp"
 
-#include <xo/object2/array/IGCObject_DArray.hpp>
-#include <xo/object2/list/IGCObject_DList.hpp>
-#include <xo/object2/boolean/IGCObject_DBoolean.hpp>
-#include <xo/object2/number/IGCObject_DFloat.hpp>
-#include <xo/object2/number/IGCObject_DInteger.hpp>
-#include <xo/object2/string/IGCObject_DString.hpp>
+#include <xo/object2/Array.hpp>
+//#include <xo/object2/List.hpp>
+#include <xo/object2/Boolean.hpp>
+#include <xo/object2/Integer.hpp>
+#include <xo/object2/Float.hpp>
+#include <xo/object2/String.hpp>
 
-#include <xo/object2/array/IPrintable_DArray.hpp>
+//#include <xo/object2/array/IGCObject_DArray.hpp>
+#include <xo/object2/list/IGCObject_DList.hpp>
+//#include <xo/object2/boolean/IGCObject_DBoolean.hpp>
+//#include <xo/object2/number/IGCObject_DFloat.hpp>
+//#include <xo/object2/number/IGCObject_DInteger.hpp>
+//#include <xo/object2/string/IGCObject_DString.hpp>
+
+//#include <xo/object2/array/IPrintable_DArray.hpp>
 #include <xo/object2/list/IPrintable_DList.hpp>
-#include <xo/object2/boolean/IPrintable_DBoolean.hpp>
-#include <xo/object2/number/IPrintable_DFloat.hpp>
-#include <xo/object2/number/IPrintable_DInteger.hpp>
-#include <xo/object2/string/IPrintable_DString.hpp>
+//#include <xo/object2/boolean/IPrintable_DBoolean.hpp>
+//#include <xo/object2/number/IPrintable_DFloat.hpp>
+//#include <xo/object2/number/IPrintable_DInteger.hpp>
+//#include <xo/object2/string/IPrintable_DString.hpp>
 
 #include <xo/object2/list/ISequence_DList.hpp>
-#include <xo/object2/array/ISequence_DArray.hpp>
+//#include <xo/object2/array/ISequence_DArray.hpp>
 
 #include <xo/printable2/detail/APrintable.hpp>
 #include <xo/alloc2/alloc/AAllocator.hpp>