diff --git a/xo-expression2/CMakeLists.txt b/xo-expression2/CMakeLists.txt
index dd7ee89a..1b84df8d 100644
--- a/xo-expression2/CMakeLists.txt
+++ b/xo-expression2/CMakeLists.txt
@@ -68,6 +68,41 @@ xo_add_genfacetimpl(
 
 # ----------------------------------------------------------------
 
+# note: manual target; generated code committed to git
+xo_add_genfacetimpl(
+    TARGET xo-expression2-facetimpl-symboltable-globalsymtab
+    FACET_PKG xo_expression2
+    FACET SymbolTable
+    REPR GlobalSymtab
+    INPUT idl/ISymbolTable_DGlobalSymtab.json5
+    OUTPUT_HPP_DIR include/xo/expression2
+    OUTPUT_IMPL_SUBDIR symtab
+)
+
+# note: manual target; generated code committed to git
+xo_add_genfacetimpl(
+    TARGET xo-expression2-facetimpl-gcobject-globalsymtab
+    FACET_PKG xo_gc
+    FACET GCObject
+    REPR GlobalSymtab
+    INPUT idl/IGCObject_DGlobalSymtab.json5
+    OUTPUT_HPP_DIR include/xo/expression2
+    OUTPUT_IMPL_SUBDIR symtab
+)
+
+# note: manual target; generated code committed to git
+xo_add_genfacetimpl(
+    TARGET xo-expression2-facetimpl-printable-globalsymtab
+    FACET_PKG xo_printable2
+    FACET Printable
+    REPR GlobalSymtab
+    INPUT idl/IPrintable_DGlobalSymtab.json5
+    OUTPUT_HPP_DIR include/xo/expression2
+    OUTPUT_IMPL_SUBDIR symtab
+)
+
+# ----------------------------------------------------------------
+
 # note: manual target; generated code committed to git
 xo_add_genfacet(
     TARGET xo-expression2-facet-expression
diff --git a/xo-expression2/idl/IGCObject_DGlobalSymtab.json5 b/xo-expression2/idl/IGCObject_DGlobalSymtab.json5
new file mode 100644
index 00000000..dac8ebac
--- /dev/null
+++ b/xo-expression2/idl/IGCObject_DGlobalSymtab.json5
@@ -0,0 +1,16 @@
+{
+    mode: "implementation",
+    output_cpp_dir: "src/expression2",
+    includes: [
+        "<xo/gc/GCObject.hpp>",
+        "<xo/alloc2/Allocator.hpp>"
+    ],
+    local_types: [ ],
+    namespace1: "xo",
+    namespace2: "scm",
+    facet_idl: "idl/GCObject.json5",
+    brief: "provide AGCObject interface for DGlobalSymtab",
+    using_doxygen: true,
+    repr: "DGlobalSymtab",
+    doc: [ "implement AGCObject for DGlobalSymtab" ],
+}
diff --git a/xo-expression2/idl/IPrintable_DGlobalSymtab.json5 b/xo-expression2/idl/IPrintable_DGlobalSymtab.json5
new file mode 100644
index 00000000..151f8a90
--- /dev/null
+++ b/xo-expression2/idl/IPrintable_DGlobalSymtab.json5
@@ -0,0 +1,14 @@
+{
+    mode: "implementation",
+    output_cpp_dir: "src/expression2",
+    includes: [ "<xo/printable2/Printable.hpp>",
+                "<xo/printable2/detail/IPrintable_Xfer.hpp>" ],
+    local_types: [ ],
+    namespace1: "xo",
+    namespace2: "scm",
+    facet_idl: "idl/Printable.json5",
+    brief: "provide APrintable interface for DGlobalSymtab",
+    using_doxygen: true,
+    repr: "DGlobalSymtab",
+    doc: [ "implement APrintable for DGlobalSymtab" ],
+}
diff --git a/xo-expression2/idl/ISymbolTable_DGlobalSymtab.json5 b/xo-expression2/idl/ISymbolTable_DGlobalSymtab.json5
new file mode 100644
index 00000000..8cc1035b
--- /dev/null
+++ b/xo-expression2/idl/ISymbolTable_DGlobalSymtab.json5
@@ -0,0 +1,13 @@
+{
+    mode: "implementation",
+    output_cpp_dir: "src/expression2",
+    includes: [ ],
+    local_types: [ ],
+    namespace1: "xo",
+    namespace2: "scm",
+    facet_idl: "idl/SymbolTable.json5",
+    brief: "provide ASymbolTable interface for DGlobalSymtab",
+    using_doxygen: true,
+    repr: "DGlobalSymtab",
+    doc: [ "implement ASymbolTable for DGlobalSymtab" ],
+}
diff --git a/xo-expression2/include/xo/expression2/DGlobalSymtab.hpp b/xo-expression2/include/xo/expression2/DGlobalSymtab.hpp
index 879c7073..6ae8895b 100644
--- a/xo-expression2/include/xo/expression2/DGlobalSymtab.hpp
+++ b/xo-expression2/include/xo/expression2/DGlobalSymtab.hpp
@@ -31,6 +31,7 @@ namespace xo {
             using ACollector = xo::mm::ACollector;
             using AAllocator = xo::mm::AAllocator;
             using MemorySizeVisitor = xo::mm::MemorySizeVisitor;
+            using ppindentinfo = xo::print::ppindentinfo;
 
         public:
             /** @defgroup scm-globalsymtab-ctors constructors **/
@@ -91,6 +92,13 @@ namespace xo {
             std::size_t forward_children(obj<ACollector> gc) noexcept;
 
             ///@}
+            /** @defgroup scm-globalsymtab-printable-facet printable facet **/
+            ///@{
+
+            /** pretty-printing support **/
+            bool pretty(const ppindentinfo & ppii) const;
+
+            ///@}
 
         private:
             /** map symbols -> bindings.
diff --git a/xo-expression2/include/xo/expression2/GlobalSymtab.hpp b/xo-expression2/include/xo/expression2/GlobalSymtab.hpp
index 0c0dabf4..05ad9f4b 100644
--- a/xo-expression2/include/xo/expression2/GlobalSymtab.hpp
+++ b/xo-expression2/include/xo/expression2/GlobalSymtab.hpp
@@ -6,8 +6,8 @@
 #pragma once
 
 #include "DGlobalSymtab.hpp"
-//#include "symtab/ISymbolTable_DGlobalSymtab.hpp"
-//#include "symtab/IGCObject_DGlobalSymtab.hpp"
-//#include "symtab/IPrintable_DGlobalSymtab.hpp"
+#include "symtab/ISymbolTable_DGlobalSymtab.hpp"
+#include "symtab/IGCObject_DGlobalSymtab.hpp"
+#include "symtab/IPrintable_DGlobalSymtab.hpp"
 
 /* end GlobalSymtab.hpp */
diff --git a/xo-expression2/include/xo/expression2/symtab/IGCObject_DGlobalSymtab.hpp b/xo-expression2/include/xo/expression2/symtab/IGCObject_DGlobalSymtab.hpp
new file mode 100644
index 00000000..92149015
--- /dev/null
+++ b/xo-expression2/include/xo/expression2/symtab/IGCObject_DGlobalSymtab.hpp
@@ -0,0 +1,67 @@
+/** @file IGCObject_DGlobalSymtab.hpp
+ *
+ *  Generated automagically from ingredients:
+ *  1. code generator:
+ *       [xo-facet/codegen/genfacet]
+ *     arguments:
+ *       --input [idl/IGCObject_DGlobalSymtab.json5]
+ *  2. jinja2 template for abstract facet .hpp file:
+ *       [iface_facet_repr.hpp.j2]
+ *  3. idl for facet methods
+ *       [idl/IGCObject_DGlobalSymtab.json5]
+ **/
+
+#pragma once
+
+#include "GCObject.hpp"
+#include <xo/gc/GCObject.hpp>
+#include <xo/alloc2/Allocator.hpp>
+#include "DGlobalSymtab.hpp"
+
+namespace xo { namespace scm { class IGCObject_DGlobalSymtab; } }
+
+namespace xo {
+    namespace facet {
+        template <>
+        struct FacetImplementation<xo::mm::AGCObject,
+                                   xo::scm::DGlobalSymtab>
+        {
+            using ImplType = xo::mm::IGCObject_Xfer
+              <xo::scm::DGlobalSymtab,
+               xo::scm::IGCObject_DGlobalSymtab>;
+        };
+    }
+}
+
+namespace xo {
+    namespace scm {
+        /** @class IGCObject_DGlobalSymtab
+         **/
+        class IGCObject_DGlobalSymtab {
+        public:
+            /** @defgroup scm-gcobject-dglobalsymtab-type-traits **/
+            ///@{
+            using size_type = xo::mm::AGCObject::size_type;
+            using AAllocator = xo::mm::AGCObject::AAllocator;
+            using ACollector = xo::mm::AGCObject::ACollector;
+            using Copaque = xo::mm::AGCObject::Copaque;
+            using Opaque = xo::mm::AGCObject::Opaque;
+            ///@}
+            /** @defgroup scm-gcobject-dglobalsymtab-methods **/
+            ///@{
+            // const methods
+            /** memory consumption for this instance **/
+            static size_type shallow_size(const DGlobalSymtab & self) noexcept;
+            /** copy instance using allocator **/
+            static Opaque shallow_copy(const DGlobalSymtab & self, obj<AAllocator> mm) noexcept;
+
+            // non-const methods
+            /** during GC: forward immdiate children **/
+            static size_type forward_children(DGlobalSymtab & self, obj<ACollector> gc) noexcept;
+            ///@}
+        };
+
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/* end */
\ No newline at end of file
diff --git a/xo-expression2/include/xo/expression2/symtab/IPrintable_DGlobalSymtab.hpp b/xo-expression2/include/xo/expression2/symtab/IPrintable_DGlobalSymtab.hpp
new file mode 100644
index 00000000..3e6d065c
--- /dev/null
+++ b/xo-expression2/include/xo/expression2/symtab/IPrintable_DGlobalSymtab.hpp
@@ -0,0 +1,62 @@
+/** @file IPrintable_DGlobalSymtab.hpp
+ *
+ *  Generated automagically from ingredients:
+ *  1. code generator:
+ *       [xo-facet/codegen/genfacet]
+ *     arguments:
+ *       --input [idl/IPrintable_DGlobalSymtab.json5]
+ *  2. jinja2 template for abstract facet .hpp file:
+ *       [iface_facet_repr.hpp.j2]
+ *  3. idl for facet methods
+ *       [idl/IPrintable_DGlobalSymtab.json5]
+ **/
+
+#pragma once
+
+#include "Printable.hpp"
+#include <xo/printable2/Printable.hpp>
+#include <xo/printable2/detail/IPrintable_Xfer.hpp>
+#include "DGlobalSymtab.hpp"
+
+namespace xo { namespace scm { class IPrintable_DGlobalSymtab; } }
+
+namespace xo {
+    namespace facet {
+        template <>
+        struct FacetImplementation<xo::print::APrintable,
+                                   xo::scm::DGlobalSymtab>
+        {
+            using ImplType = xo::print::IPrintable_Xfer
+              <xo::scm::DGlobalSymtab,
+               xo::scm::IPrintable_DGlobalSymtab>;
+        };
+    }
+}
+
+namespace xo {
+    namespace scm {
+        /** @class IPrintable_DGlobalSymtab
+         **/
+        class IPrintable_DGlobalSymtab {
+        public:
+            /** @defgroup scm-printable-dglobalsymtab-type-traits **/
+            ///@{
+            using ppindentinfo = xo::print::APrintable::ppindentinfo;
+            using Copaque = xo::print::APrintable::Copaque;
+            using Opaque = xo::print::APrintable::Opaque;
+            ///@}
+            /** @defgroup scm-printable-dglobalsymtab-methods **/
+            ///@{
+            // const methods
+            /** Pretty-printing support for this object.
+See [xo-indentlog/xo/indentlog/pretty.hpp] **/
+            static bool pretty(const DGlobalSymtab & self, const ppindentinfo & ppii);
+
+            // non-const methods
+            ///@}
+        };
+
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/* end */
\ No newline at end of file
diff --git a/xo-expression2/include/xo/expression2/symtab/ISymbolTable_DGlobalSymtab.hpp b/xo-expression2/include/xo/expression2/symtab/ISymbolTable_DGlobalSymtab.hpp
new file mode 100644
index 00000000..64f90528
--- /dev/null
+++ b/xo-expression2/include/xo/expression2/symtab/ISymbolTable_DGlobalSymtab.hpp
@@ -0,0 +1,60 @@
+/** @file ISymbolTable_DGlobalSymtab.hpp
+ *
+ *  Generated automagically from ingredients:
+ *  1. code generator:
+ *       [xo-facet/codegen/genfacet]
+ *     arguments:
+ *       --input [idl/ISymbolTable_DGlobalSymtab.json5]
+ *  2. jinja2 template for abstract facet .hpp file:
+ *       [iface_facet_repr.hpp.j2]
+ *  3. idl for facet methods
+ *       [idl/ISymbolTable_DGlobalSymtab.json5]
+ **/
+
+#pragma once
+
+#include "SymbolTable.hpp"
+#include "DGlobalSymtab.hpp"
+
+namespace xo { namespace scm { class ISymbolTable_DGlobalSymtab; } }
+
+namespace xo {
+    namespace facet {
+        template <>
+        struct FacetImplementation<xo::scm::ASymbolTable,
+                                   xo::scm::DGlobalSymtab>
+        {
+            using ImplType = xo::scm::ISymbolTable_Xfer
+              <xo::scm::DGlobalSymtab,
+               xo::scm::ISymbolTable_DGlobalSymtab>;
+        };
+    }
+}
+
+namespace xo {
+    namespace scm {
+        /** @class ISymbolTable_DGlobalSymtab
+         **/
+        class ISymbolTable_DGlobalSymtab {
+        public:
+            /** @defgroup scm-symboltable-dglobalsymtab-type-traits **/
+            ///@{
+            using Copaque = xo::scm::ASymbolTable::Copaque;
+            using Opaque = xo::scm::ASymbolTable::Opaque;
+            ///@}
+            /** @defgroup scm-symboltable-dglobalsymtab-methods **/
+            ///@{
+            // const methods
+            /** true iff this is toplevel (global) symbol table. **/
+            static bool is_global_symtab(const DGlobalSymtab & self) noexcept;
+            /** report ingredients needed to address variable at runtime. **/
+            static Binding lookup_binding(const DGlobalSymtab & self, const DUniqueString * sym) noexcept;
+
+            // non-const methods
+            ///@}
+        };
+
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/* end */
\ No newline at end of file
diff --git a/xo-expression2/src/expression2/CMakeLists.txt b/xo-expression2/src/expression2/CMakeLists.txt
index 749910e4..8aafa01a 100644
--- a/xo-expression2/src/expression2/CMakeLists.txt
+++ b/xo-expression2/src/expression2/CMakeLists.txt
@@ -58,6 +58,9 @@ set(SELF_SRCS
     IPrintable_DLocalSymtab.cpp
 
     DGlobalSymtab.cpp
+    ISymbolTable_DGlobalSymtab.cpp
+    IGCObject_DGlobalSymtab.cpp
+    IPrintable_DGlobalSymtab.cpp
 
     StringTable.cpp
 
diff --git a/xo-expression2/src/expression2/DGlobalSymtab.cpp b/xo-expression2/src/expression2/DGlobalSymtab.cpp
index c9897670..70b953dd 100644
--- a/xo-expression2/src/expression2/DGlobalSymtab.cpp
+++ b/xo-expression2/src/expression2/DGlobalSymtab.cpp
@@ -168,6 +168,18 @@ namespace xo {
             return this->shallow_size();
         }
 
+        // ----- printable facet -----
+
+        bool
+        DGlobalSymtab::pretty(const ppindentinfo & ppii) const
+        {
+            return ppii.pps()->pretty_struct
+                       (ppii,
+                        "DGlobalSymtab",
+                        refrtag("nsym", vars_->size()),
+                        refrtag("capacity", vars_->capacity()));
+        }
+
     } /*namespace scm*/
 } /*namespace xo*/
 
diff --git a/xo-expression2/src/expression2/IGCObject_DGlobalSymtab.cpp b/xo-expression2/src/expression2/IGCObject_DGlobalSymtab.cpp
new file mode 100644
index 00000000..d59e6bbf
--- /dev/null
+++ b/xo-expression2/src/expression2/IGCObject_DGlobalSymtab.cpp
@@ -0,0 +1,39 @@
+/** @file IGCObject_DGlobalSymtab.cpp
+ *
+ *  Generated automagically from ingredients:
+ *  1. code generator:
+ *       [xo-facet/codegen/genfacet]
+ *     arguments:
+ *       --input [idl/IGCObject_DGlobalSymtab.json5]
+ *  2. jinja2 template for abstract facet .hpp file:
+ *       [iface_facet_any.hpp.j2]
+ *  3. idl for facet methods
+ *       [idl/IGCObject_DGlobalSymtab.json5]
+**/
+
+#include "symtab/IGCObject_DGlobalSymtab.hpp"
+
+namespace xo {
+    namespace scm {
+        auto
+        IGCObject_DGlobalSymtab::shallow_size(const DGlobalSymtab & self) noexcept -> size_type
+        {
+            return self.shallow_size();
+        }
+
+        auto
+        IGCObject_DGlobalSymtab::shallow_copy(const DGlobalSymtab & self, obj<AAllocator> mm) noexcept -> Opaque
+        {
+            return self.shallow_copy(mm);
+        }
+
+        auto
+        IGCObject_DGlobalSymtab::forward_children(DGlobalSymtab & self, obj<ACollector> gc) noexcept -> size_type
+        {
+            return self.forward_children(gc);
+        }
+
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/* end IGCObject_DGlobalSymtab.cpp */
diff --git a/xo-expression2/src/expression2/IPrintable_DGlobalSymtab.cpp b/xo-expression2/src/expression2/IPrintable_DGlobalSymtab.cpp
new file mode 100644
index 00000000..35ecf6e7
--- /dev/null
+++ b/xo-expression2/src/expression2/IPrintable_DGlobalSymtab.cpp
@@ -0,0 +1,28 @@
+/** @file IPrintable_DGlobalSymtab.cpp
+ *
+ *  Generated automagically from ingredients:
+ *  1. code generator:
+ *       [xo-facet/codegen/genfacet]
+ *     arguments:
+ *       --input [idl/IPrintable_DGlobalSymtab.json5]
+ *  2. jinja2 template for abstract facet .hpp file:
+ *       [iface_facet_any.hpp.j2]
+ *  3. idl for facet methods
+ *       [idl/IPrintable_DGlobalSymtab.json5]
+**/
+
+#include "symtab/IPrintable_DGlobalSymtab.hpp"
+
+namespace xo {
+    namespace scm {
+        auto
+        IPrintable_DGlobalSymtab::pretty(const DGlobalSymtab & self, const ppindentinfo & ppii) -> bool
+        {
+            return self.pretty(ppii);
+        }
+
+
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/* end IPrintable_DGlobalSymtab.cpp */
diff --git a/xo-expression2/src/expression2/ISymbolTable_DGlobalSymtab.cpp b/xo-expression2/src/expression2/ISymbolTable_DGlobalSymtab.cpp
new file mode 100644
index 00000000..b735a6fb
--- /dev/null
+++ b/xo-expression2/src/expression2/ISymbolTable_DGlobalSymtab.cpp
@@ -0,0 +1,34 @@
+/** @file ISymbolTable_DGlobalSymtab.cpp
+ *
+ *  Generated automagically from ingredients:
+ *  1. code generator:
+ *       [xo-facet/codegen/genfacet]
+ *     arguments:
+ *       --input [idl/ISymbolTable_DGlobalSymtab.json5]
+ *  2. jinja2 template for abstract facet .hpp file:
+ *       [iface_facet_any.hpp.j2]
+ *  3. idl for facet methods
+ *       [idl/ISymbolTable_DGlobalSymtab.json5]
+**/
+
+#include "symtab/ISymbolTable_DGlobalSymtab.hpp"
+
+namespace xo {
+    namespace scm {
+        auto
+        ISymbolTable_DGlobalSymtab::is_global_symtab(const DGlobalSymtab & self) noexcept -> bool
+        {
+            return self.is_global_symtab();
+        }
+
+        auto
+        ISymbolTable_DGlobalSymtab::lookup_binding(const DGlobalSymtab & self, const DUniqueString * sym) noexcept -> Binding
+        {
+            return self.lookup_binding(sym);
+        }
+
+
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/* end ISymbolTable_DGlobalSymtab.cpp */
diff --git a/xo-expression2/src/expression2/expression2_register_facets.cpp b/xo-expression2/src/expression2/expression2_register_facets.cpp
index a3a4b520..c563c9da 100644
--- a/xo-expression2/src/expression2/expression2_register_facets.cpp
+++ b/xo-expression2/src/expression2/expression2_register_facets.cpp
@@ -6,8 +6,8 @@
 #include "expression2_register_facets.hpp"
 
 #include <xo/expression2/UniqueString.hpp>
-#include <xo/expression2/detail/IGCObject_DUniqueString.hpp>
-#include <xo/expression2/detail/IPrintable_DUniqueString.hpp>
+//#include <xo/expression2/detail/IGCObject_DUniqueString.hpp>
+//#include <xo/expression2/detail/IPrintable_DUniqueString.hpp>
 
 #include <xo/expression2/detail/IExpression_DDefineExpr.hpp>
 //#include <xo/expression2/detail/IGCObject_DDefineExpr.hpp>
@@ -101,6 +101,10 @@ namespace xo {
             FacetRegistry::register_impl<AGCObject, DLocalSymtab>();
             FacetRegistry::register_impl<APrintable, DLocalSymtab>();
 
+            FacetRegistry::register_impl<ASymbolTable, DGlobalSymtab>();
+            FacetRegistry::register_impl<AGCObject, DGlobalSymtab>();
+            FacetRegistry::register_impl<APrintable, DGlobalSymtab>();
+
             // until we register facets
             TypeRegistry::register_type<DGlobalSymtab>();