From b64dee41cb285b7376d61fcfd3564d08fdddc963 Mon Sep 17 00:00:00 2001
From: Roland Conybeare <rconybeare@gmail.com>
Date: Tue, 17 Feb 2026 14:42:17 -0500
Subject: [PATCH] xo-interpreter2 stack: define-expr's work at top-level

---
 include/xo/object2/DArray.hpp | 12 +++++++++---
 src/object2/DArray.cpp        | 13 +++++++++++++
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/include/xo/object2/DArray.hpp b/include/xo/object2/DArray.hpp
index 7b75886..8d7248e 100644
--- a/include/xo/object2/DArray.hpp
+++ b/include/xo/object2/DArray.hpp
@@ -75,9 +75,6 @@ namespace xo {
                 requires (std::same_as<Args, obj<AGCObject>> && ...)
             static DArray * array(obj<AAllocator> mm, Args... args);
 
-            const obj<AGCObject> & operator[](size_type index) const noexcept { return elts_[index]; }
-            obj<AGCObject> & operator[](size_type index) noexcept { return elts_[index]; }
-
             ///@}
             /** @defgroup darray-access acecss methods **/
             ///@{
@@ -91,6 +88,10 @@ namespace xo {
             size_type size() const noexcept { return size_; }
             /** return element @p index of this array (0-based) **/
             obj<AGCObject> at(size_type index) const;
+
+            const obj<AGCObject> & operator[](size_type index) const noexcept { return elts_[index]; }
+            obj<AGCObject> & operator[](size_type index) noexcept { return elts_[index]; }
+
             ///@}
             /** @defgroup darray-iterators iterators **/
             ///@{
@@ -106,6 +107,11 @@ namespace xo {
             /** @defgroup darray-general general methods **/
             ///@{
 
+            /** resize to @p new_size.  @p new_size may not be larger than capacity
+             *  Return true if resize was accomplished; false otherwise.
+             **/
+            bool resize(size_type new_size) noexcept;
+
             ///@}
             /** @defgroup darray-conversion-operators conversion operators **/
             ///@{
diff --git a/src/object2/DArray.cpp b/src/object2/DArray.cpp
index e1414ee..31ced92 100644
--- a/src/object2/DArray.cpp
+++ b/src/object2/DArray.cpp
@@ -84,6 +84,19 @@ namespace xo {
             }
         }
 
+        bool
+        DArray::resize(size_type new_z) noexcept {
+            if (new_z >= capacity_) {
+                return false;
+            } else if (new_z > size_) {
+                // ensure new size is zeroed (we/re not zeroing if/when we shrink)
+                ::memset((std::byte *)(&elts_[size_]), 0, (std::byte *)(&elts_[new_z]) - (std::byte *)(&elts_[size_]));
+            }
+
+            this->size_ = new_z;
+            return true;
+        }
+
         // printing support
 
         bool