diff --git a/include/xo/expression2/DLambdaExpr.hpp b/include/xo/expression2/DLambdaExpr.hpp
index 14be115f..2a0cc2c3 100644
--- a/include/xo/expression2/DLambdaExpr.hpp
+++ b/include/xo/expression2/DLambdaExpr.hpp
@@ -23,6 +23,7 @@ namespace xo {
             using AAllocator = xo::mm::AAllocator;
             using TypeDescr = xo::reflect::TypeDescr;
             using ppindentinfo = xo::print::ppindentinfo;
+            using size_type = DLocalSymtab::size_type;
 
         public:
 
@@ -60,6 +61,7 @@ namespace xo {
             ///@{
 
             DLocalSymtab * local_symtab() const noexcept { return local_symtab_; }
+            size_type n_args() const noexcept { return local_symtab_->size(); }
 
             // get_free_variables()
             // visit_preorder()
diff --git a/include/xo/expression2/DLocalSymtab.hpp b/include/xo/expression2/DLocalSymtab.hpp
index 01d9aa85..163d031e 100644
--- a/include/xo/expression2/DLocalSymtab.hpp
+++ b/include/xo/expression2/DLocalSymtab.hpp
@@ -101,7 +101,7 @@ namespace xo {
         private:
             /** parent symbol table from scoping surrounding this one **/
             DLocalSymtab * parent_ = nullptr;
-            /** actual range of slots_[] array.  Can use inices in [0,..,n) **/
+            /** actual range of slots_[] array.  Can use indices in [0,..,n) **/
             size_type capacity_ = 0;
             /** number of slots in use **/
             size_type size_ = 0;
diff --git a/include/xo/expression2/LambdaExpr.hpp b/include/xo/expression2/LambdaExpr.hpp
new file mode 100644
index 00000000..45f86b25
--- /dev/null
+++ b/include/xo/expression2/LambdaExpr.hpp
@@ -0,0 +1,13 @@
+/** @file LambdaExpr.hpp
+ *
+ *  @author Roland Conybeare, Feb 2026
+ **/
+
+#pragma once
+
+#include "DLambdaExpr.hpp"
+#include "detail/IExpression_DLambdaExpr.hpp"
+//#include "detail/IGCObject_DLambdaExpr.hpp"
+#include "detail/IPrintable_DLambdaExpr.hpp"
+
+/* end LambdaExpr.hpp */
diff --git a/include/xo/expression2/LocalSymtab.hpp b/include/xo/expression2/LocalSymtab.hpp
new file mode 100644
index 00000000..4c852652
--- /dev/null
+++ b/include/xo/expression2/LocalSymtab.hpp
@@ -0,0 +1,12 @@
+/** @file LocalSymtab.hpp
+ *
+ *  @author Roland Conybeare, Feb 2026
+ **/
+
+#pragma once
+
+#include "DLocalSymtab.hpp"
+#include "symtab/ISymbolTable_DLocalSymtab.hpp"
+#include "symtab/IPrintable_DLocalSymtab.hpp"
+
+/* end LocalSymtab.hpp */