diff --git a/idl/RuntimeContext.json5 b/idl/RuntimeContext.json5
index 46623b4..fe1254b 100644
--- a/idl/RuntimeContext.json5
+++ b/idl/RuntimeContext.json5
@@ -5,6 +5,7 @@
     output_impl_subdir: "detail",
     // includes in ARuntimeContext.hpp
     includes: [
+        "<xo/stringtable2/StringTable.hpp>",
         "<xo/alloc2/Allocator.hpp>",
         "<xo/arena/MemorySizeInfo.hpp>"
     ],
@@ -46,6 +47,15 @@
             noexcept: true,
             attributes: [],
         },
+        {
+            name: "stringtable",
+            doc: [ "stringtable for unique symbols" ],
+            return_type: "StringTable *",
+            args: [],
+            const: true,
+            noexcept: true,
+            attributes: [],
+        },
         {
             name: "visit_pools",
             doc: [ "invoke visitor for each distinct memory pool" ],
diff --git a/include/xo/procedure2/DPrimitive.hpp b/include/xo/procedure2/DPrimitive.hpp
index 07c19c4..4331057 100644
--- a/include/xo/procedure2/DPrimitive.hpp
+++ b/include/xo/procedure2/DPrimitive.hpp
@@ -87,27 +87,36 @@ namespace xo {
             /** @defgroup scm-primitive-ctors constructors **/
             ///@{
 
-            Primitive(std::string_view name, Fn fn)
+            Primitive(std::string_view name, obj<AType> type, Fn fn)
                 : name_{name},
+                  type_{type},
                   fn_td_{Reflect::require<Fn>()},
                   fn_{fn} {}
 
             static Primitive * _make(obj<AAllocator> mm, std::string_view name, Fn fn) {
                 void * mem = mm.alloc_for<Primitive>();
 
-                return new (mem) Primitive(name, fn);
+                return new (mem) Primitive(name, obj<AType>(), fn);
             }
 
+            static Primitive * _make(obj<AAllocator> mm,
+                                     std::string_view name,
+                                     obj<AType> type,
+                                     Fn fn)
+                {
+                    void * mem = mm.alloc_for<Primitive>();
+
+                    return new (mem) Primitive(name, type, fn);
+                }
+
             ///@}
             /** @defgroup scm-primitive-methods general methods **/
             ///@{
 
-            TypeDescr fn_td() const noexcept { return fn_td_; }
-
-            std::string_view name() const noexcept { return name_; }
-
             static constexpr std::int32_t n_args() noexcept { return Traits::n_args; }
 
+            TypeDescr fn_td() const noexcept { return fn_td_; }
+            std::string_view name() const noexcept { return name_; }
             bool is_nary() const noexcept { return false; }
 
             obj<AGCObject> apply_nocheck(obj<ARuntimeContext> rcx, const DArray * args) {
diff --git a/include/xo/procedure2/DSimpleRcx.hpp b/include/xo/procedure2/DSimpleRcx.hpp
index 1efb802..6a7163d 100644
--- a/include/xo/procedure2/DSimpleRcx.hpp
+++ b/include/xo/procedure2/DSimpleRcx.hpp
@@ -5,6 +5,7 @@
 
 #pragma once
 
+#include <xo/stringtable2/StringTable.hpp>
 #include <xo/alloc2/Allocator.hpp>
 
 namespace xo {
@@ -21,13 +22,16 @@ namespace xo {
             using MemorySizeVisitor = xo::mm::MemorySizeVisitor;
 
         public:
-            DSimpleRcx(obj<AAllocator> mm) : allocator_{mm} {}
+            DSimpleRcx(obj<AAllocator> mm, StringTable * st)
+                : allocator_{mm}, stringtable_{st} {}
 
             obj<AAllocator> allocator() const noexcept { return allocator_; }
+            StringTable * stringtable() const noexcept { return stringtable_; }
             void visit_pools(const MemorySizeVisitor & visitor) const;
 
         private:
             obj<AAllocator> allocator_;
+            StringTable * stringtable_ = nullptr;
         };
 
     } /*namespace scm*/
diff --git a/include/xo/procedure2/detail/ARuntimeContext.hpp b/include/xo/procedure2/detail/ARuntimeContext.hpp
index 820dd8d..716463d 100644
--- a/include/xo/procedure2/detail/ARuntimeContext.hpp
+++ b/include/xo/procedure2/detail/ARuntimeContext.hpp
@@ -14,6 +14,7 @@
 #pragma once
 
 // includes (via {facet_includes})
+#include <xo/stringtable2/StringTable.hpp>
 #include <xo/alloc2/Allocator.hpp>
 #include <xo/arena/MemorySizeInfo.hpp>
 #include <xo/facet/obj.hpp>
@@ -54,6 +55,8 @@ public:
     virtual void _drop(Opaque d) const noexcept = 0;
     /** default allocator to use for objects **/
     virtual obj<AAllocator> allocator(Copaque data)  const  noexcept = 0;
+    /** stringtable for unique symbols **/
+    virtual StringTable * stringtable(Copaque data)  const  noexcept = 0;
     /** invoke visitor for each distinct memory pool **/
     virtual void visit_pools(Copaque data, MemorySizeVisitor visitor)  const = 0;
 
diff --git a/include/xo/procedure2/detail/IRuntimeContext_Any.hpp b/include/xo/procedure2/detail/IRuntimeContext_Any.hpp
index 2caa9d3..b72f934 100644
--- a/include/xo/procedure2/detail/IRuntimeContext_Any.hpp
+++ b/include/xo/procedure2/detail/IRuntimeContext_Any.hpp
@@ -61,6 +61,7 @@ namespace scm {
 
         // const methods
         [[noreturn]] obj<AAllocator> allocator(Copaque)  const  noexcept override { _fatal(); }
+        [[noreturn]] StringTable * stringtable(Copaque)  const  noexcept override { _fatal(); }
         [[noreturn]] void visit_pools(Copaque, MemorySizeVisitor)  const override { _fatal(); }
 
         // nonconst methods
diff --git a/include/xo/procedure2/detail/IRuntimeContext_DSimpleRcx.hpp b/include/xo/procedure2/detail/IRuntimeContext_DSimpleRcx.hpp
index 62d3e12..82ab521 100644
--- a/include/xo/procedure2/detail/IRuntimeContext_DSimpleRcx.hpp
+++ b/include/xo/procedure2/detail/IRuntimeContext_DSimpleRcx.hpp
@@ -49,6 +49,8 @@ namespace xo {
             // const methods
             /** default allocator to use for objects **/
             static obj<AAllocator> allocator(const DSimpleRcx & self) noexcept;
+            /** stringtable for unique symbols **/
+            static StringTable * stringtable(const DSimpleRcx & self) noexcept;
             /** invoke visitor for each distinct memory pool **/
             static void visit_pools(const DSimpleRcx & self, MemorySizeVisitor visitor);
 
diff --git a/include/xo/procedure2/detail/IRuntimeContext_Xfer.hpp b/include/xo/procedure2/detail/IRuntimeContext_Xfer.hpp
index 6257abb..5dc9de5 100644
--- a/include/xo/procedure2/detail/IRuntimeContext_Xfer.hpp
+++ b/include/xo/procedure2/detail/IRuntimeContext_Xfer.hpp
@@ -13,6 +13,7 @@
 
 #pragma once
 
+#include <xo/stringtable2/StringTable.hpp>
 #include <xo/alloc2/Allocator.hpp>
 #include <xo/arena/MemorySizeInfo.hpp>
 
@@ -49,6 +50,9 @@ namespace scm {
         obj<AAllocator> allocator(Copaque data)  const  noexcept override {
             return I::allocator(_dcast(data));
         }
+        StringTable * stringtable(Copaque data)  const  noexcept override {
+            return I::stringtable(_dcast(data));
+        }
         void visit_pools(Copaque data, MemorySizeVisitor visitor)  const override {
             return I::visit_pools(_dcast(data), visitor);
         }
diff --git a/include/xo/procedure2/detail/RRuntimeContext.hpp b/include/xo/procedure2/detail/RRuntimeContext.hpp
index 5840743..6553648 100644
--- a/include/xo/procedure2/detail/RRuntimeContext.hpp
+++ b/include/xo/procedure2/detail/RRuntimeContext.hpp
@@ -57,6 +57,9 @@ public:
     obj<AAllocator> allocator()  const  noexcept {
         return O::iface()->allocator(O::data());
     }
+    StringTable * stringtable()  const  noexcept {
+        return O::iface()->stringtable(O::data());
+    }
     void visit_pools(MemorySizeVisitor visitor)  const {
         return O::iface()->visit_pools(O::data(), visitor);
     }
diff --git a/src/procedure2/ObjectPrimitives.cpp b/src/procedure2/ObjectPrimitives.cpp
index fcb8ba2..c247ab8 100644
--- a/src/procedure2/ObjectPrimitives.cpp
+++ b/src/procedure2/ObjectPrimitives.cpp
@@ -75,6 +75,8 @@ namespace xo {
 
             auto cdr_list = obj<AGCObject,DList>::from(cdr);
 
+            //auto T = DTypeVarRef::_make(rcx.allocator(), "T");
+
             return DList::cons(rcx.allocator(),
                                car,
                                cdr_list.data());
diff --git a/src/procedure2/facet/IRuntimeContext_DSimpleRcx.cpp b/src/procedure2/facet/IRuntimeContext_DSimpleRcx.cpp
index 2331b7c..82dd310 100644
--- a/src/procedure2/facet/IRuntimeContext_DSimpleRcx.cpp
+++ b/src/procedure2/facet/IRuntimeContext_DSimpleRcx.cpp
@@ -21,6 +21,12 @@ namespace xo {
             return self.allocator();
         }
 
+        auto
+        IRuntimeContext_DSimpleRcx::stringtable(const DSimpleRcx & self) noexcept -> StringTable *
+        {
+            return self.stringtable();
+        }
+
         auto
         IRuntimeContext_DSimpleRcx::visit_pools(const DSimpleRcx & self, MemorySizeVisitor visitor) -> void
         {
diff --git a/utest/DSimpleRcx.test.cpp b/utest/DSimpleRcx.test.cpp
index cab1362..365bd3f 100644
--- a/utest/DSimpleRcx.test.cpp
+++ b/utest/DSimpleRcx.test.cpp
@@ -6,12 +6,14 @@
 #include <xo/procedure2/init_procedure2.hpp>
 #include <xo/procedure2/DSimpleRcx.hpp>
 #include <xo/procedure2/detail/IRuntimeContext_DSimpleRcx.hpp>
+#include <xo/stringtable2/StringTable.hpp>
 #include <xo/alloc2/arena/IAllocator_DArena.hpp>
 #include <catch2/catch.hpp>
 
 namespace xo {
     using xo::scm::DSimpleRcx;
     using xo::scm::ARuntimeContext;
+    using xo::scm::StringTable;
     using xo::mm::AAllocator;
     using xo::mm::DArena;
     using xo::mm::ArenaConfig;
@@ -30,12 +32,17 @@ namespace xo {
         {
             ArenaConfig cfg { .name_ = "testarena",
                               .size_ = 4*1024 };
+
             DArena arena = DArena::map(cfg);
             auto alloc = with_facet<AAllocator>::mkobj(&arena);
 
-            DSimpleRcx rcx(alloc);
+            auto stbl = StringTable(1024 /*hint_max_capacity*/,
+                                    false /*!debug_flag*/);
+
+            DSimpleRcx rcx(alloc, &stbl);
 
             REQUIRE((void*)rcx.allocator().data() == (void*)alloc.data());
+            REQUIRE(rcx.stringtable() == &stbl);
         }
 
         TEST_CASE("DSimpleRcx-as-ARuntimeContext", "[procedure2][DSimpleRcx]")
@@ -44,8 +51,10 @@ namespace xo {
                               .size_ = 4*1024 };
             DArena arena = DArena::map(cfg);
             auto alloc = with_facet<AAllocator>::mkobj(&arena);
+            auto stbl = StringTable(1024 /*hint_max_capacity*/,
+                                    false /*!debug_flag*/);
 
-            DSimpleRcx rcx(alloc);
+            DSimpleRcx rcx(alloc, &stbl);
             obj<ARuntimeContext> rcx_obj = with_facet<ARuntimeContext>::mkobj(&rcx);
 
             // verify we can recover allocator from obj<ARuntimeContext>