diff --git a/include/xo/interpreter2/DGlobalEnv.hpp b/include/xo/interpreter2/DGlobalEnv.hpp
index e68ad55d..e2df166b 100644
--- a/include/xo/interpreter2/DGlobalEnv.hpp
+++ b/include/xo/interpreter2/DGlobalEnv.hpp
@@ -25,6 +25,7 @@ namespace xo {
          **/
         class DGlobalEnv {
         public:
+            using TypeDescr = xo::reflect::TypeDescr;
             using ACollector = xo::mm::ACollector;
             using AAllocator = xo::mm::AAllocator;
             using AGCObject = xo::mm::AGCObject;
@@ -57,6 +58,14 @@ namespace xo {
              **/
             void assign_value(obj<AAllocator> mm, Binding ix, obj<AGCObject> x);
 
+            /** create/establish global for symbol @p sym with resolved type @p td
+             *  and associate with @p value.
+             **/
+            DVariable * _upsert_value(obj<AAllocator> mm,
+                                      const DUniqueString * sym,
+                                      TypeDescr td,
+                                      obj<AGCObject> value);
+
             ///@}
             /** @defgroup scm-globalenv-gcobject-facet **/
             ///@{
diff --git a/src/interpreter2/DGlobalEnv.cpp b/src/interpreter2/DGlobalEnv.cpp
index a9285b73..2ad6c1ba 100644
--- a/src/interpreter2/DGlobalEnv.cpp
+++ b/src/interpreter2/DGlobalEnv.cpp
@@ -88,6 +88,23 @@ namespace xo {
             (*values_)[ix.j_slot()] = x;
         }
 
+        DVariable *
+        DGlobalEnv::_upsert_value(obj<AAllocator> mm,
+                                  const DUniqueString * sym,
+                                  TypeDescr td,
+                                  obj<AGCObject> value)
+        {
+            DVariable * var
+                = DVariable::make(mm, sym, TypeRef::resolved(td));
+
+            assert(var);
+
+            symtab_->upsert_variable(mm, var);
+            this->assign_value(mm, var->path(), value);
+
+            return var;
+        }
+
         // ----- AGCObject facet -----
 
         std::size_t