From 8f1361763e50b8e1cf0e6096c3d60c0e97b5cb68 Mon Sep 17 00:00:00 2001
From: Roland Conybeare <rconybeare@gmail.com>
Date: Sun, 11 Jan 2026 12:32:02 -0500
Subject: [PATCH] xo-object2: streamline DList::list use

---
 include/xo/object2/DList.hpp | 30 ++++++++++++++++++++++++++++++
 src/object2/DList.cpp        |  2 ++
 utest/X1Collector.test.cpp   |  5 +++--
 3 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/include/xo/object2/DList.hpp b/include/xo/object2/DList.hpp
index 1e863a6..b023f0d 100644
--- a/include/xo/object2/DList.hpp
+++ b/include/xo/object2/DList.hpp
@@ -34,6 +34,17 @@ namespace xo {
                                               obj<AGCObject> car,
                                               obj<ACdrFacet,DList> cdr);
 
+            /** list with one element @p e1, allocated from @p mm **/
+            template <typename AListFacet = AGCObject>
+            static obj<AListFacet,DList> list(obj<AAllocator> mm,
+                                              obj<AGCObject> e1);
+
+            /** list with two element @p e1, @p e2, allocated from @p mm **/
+            template <typename AListFacet = AGCObject>
+            static obj<AListFacet,DList> list(obj<AAllocator> mm,
+                                              obj<AGCObject> e1,
+                                              obj<AGCObject> e2);
+
             /** sentinel for null list **/
             static DList * _nil();
 
@@ -45,6 +56,7 @@ namespace xo {
                                  obj<AGCObject> car,
                                  DList * cdr);
 
+#ifdef OBSOLETE
             /** list with one element @p h1, allocated from @p mm **/
             static DList * list(obj<AAllocator> mm,
                                 obj<AGCObject> h1);
@@ -52,6 +64,7 @@ namespace xo {
             static DList * list(obj<AAllocator> mm,
                                 obj<AGCObject> h1,
                                 obj<AGCObject> h2);
+#endif
 
             /** DList length is at least 1 **/
             bool is_empty() const noexcept;
@@ -87,6 +100,23 @@ namespace xo {
             return obj<AConsFacet,DList>(DList::_cons(mm, car, cdr.data()));
         }
 
+        template <typename AListFacet>
+        obj<AListFacet,DList>
+        DList::list(obj<AAllocator> mm,
+                    obj<AGCObject> e1)
+        {
+            return cons(mm, e1, nil());
+        }
+
+        template <typename AListFacet>
+        obj<AListFacet,DList>
+        DList::list(obj<AAllocator> mm,
+                    obj<AGCObject> e1,
+                    obj<AGCObject> e2)
+        {
+            return cons(mm, e1, list(mm, e2));
+        }
+
     } /*namespace scm*/
 } /*namespace xo*/
 
diff --git a/src/object2/DList.cpp b/src/object2/DList.cpp
index 777d503..934fa50 100644
--- a/src/object2/DList.cpp
+++ b/src/object2/DList.cpp
@@ -34,6 +34,7 @@ namespace xo {
             return new (mem) DList(car, cdr);
         }
 
+#ifdef OBSOLETE
         DList *
         DList::list(obj<AAllocator> mm,
                     obj<AGCObject> h1)
@@ -52,6 +53,7 @@ namespace xo {
 
             return new (mem) DList(h1, DList::list(mm, h2));
         }
+#endif
 
         bool
         DList::is_empty() const noexcept
diff --git a/utest/X1Collector.test.cpp b/utest/X1Collector.test.cpp
index cec744e..1536ebf 100644
--- a/utest/X1Collector.test.cpp
+++ b/utest/X1Collector.test.cpp
@@ -171,8 +171,9 @@ namespace ut {
                 c_o.add_gc_root(&x0_o);
                 REQUIRE(to_0->allocated() == sizeof(AllocHeader) + sizeof(DFloat));
 
-                DList * l0 = DList::list(gc_o, x0_o);
-                auto l0_o = with_facet<AGCObject>::mkobj(l0);
+                //DList * l0 = DList::list(gc_o, x0_o);
+                //auto l0_o = with_facet<AGCObject>::mkobj(l0);
+                auto l0_o = DList::list(gc_o, x0_o);
                 c_o.add_gc_root(&l0_o);
                 REQUIRE(to_0->allocated() == (sizeof(AllocHeader) + sizeof(DFloat)
                                               + sizeof(AllocHeader) + sizeof(DList)));