From 0bcd97685e124981ea4cfd92411cc57018307811 Mon Sep 17 00:00:00 2001
From: Roland Conybeare <rconybeare@gmail.com>
Date: Mon, 19 Jan 2026 21:25:30 -0500
Subject: [PATCH] xo-reader2 xo-expresion2: work on define-expressions [WIP]

---
 include/xo/interpreter2/VirtualSchematikaMachine.hpp |  6 ++++++
 src/interpreter2/VirtualSchematikaMachine.cpp        | 10 ++++++++++
 2 files changed, 16 insertions(+)

diff --git a/include/xo/interpreter2/VirtualSchematikaMachine.hpp b/include/xo/interpreter2/VirtualSchematikaMachine.hpp
index 8bbe6bb4..a149173e 100644
--- a/include/xo/interpreter2/VirtualSchematikaMachine.hpp
+++ b/include/xo/interpreter2/VirtualSchematikaMachine.hpp
@@ -45,6 +45,12 @@ namespace xo {
              **/
             void _do_eval_constant_op();
 
+            /** evaluate a define-expression
+             *  Require:
+             *  - expression in @ref expr_
+             **/
+            void _do_eval_define_op();
+
             /** evaluate a variable expression
              *  Require:
              *  - expression in @ref expr_
diff --git a/src/interpreter2/VirtualSchematikaMachine.cpp b/src/interpreter2/VirtualSchematikaMachine.cpp
index bd29e968..f7131e0a 100644
--- a/src/interpreter2/VirtualSchematikaMachine.cpp
+++ b/src/interpreter2/VirtualSchematikaMachine.cpp
@@ -45,6 +45,9 @@ namespace xo {
             case exprtype::constant:
                 _do_eval_constant_op();
                 break;
+            case exprtype::define:
+                _do_eval_define_op();
+                break;
             case exprtype::variable:
                 _do_eval_variable_op();
                 break;
@@ -61,6 +64,13 @@ namespace xo {
             this->pc_ = this->cont_;
         }
 
+        void
+        VirtualSchematikaMachine::_do_eval_define_op()
+        {
+            // not implemented
+            assert(false);
+        }
+
         void
         VirtualSchematikaMachine::_do_eval_variable_op()
         {