From 111df958f55155e3a15bb3d740f031cf77e4e980 Mon Sep 17 00:00:00 2001
From: Roland Conybeare <rconybeare@gmail.com>
Date: Fri, 16 Jan 2026 19:04:08 -0500
Subject: [PATCH] xo-expression2: symtab scaffold [WIP] [COSMETIC]

---
 xo-expression2/idl/ASymbolTable.json5         | 41 ++++++++++++++
 .../include/xo/expression2/DLocalSymtab.hpp   | 54 +++++++++++++++++++
 2 files changed, 95 insertions(+)
 create mode 100644 xo-expression2/idl/ASymbolTable.json5
 create mode 100644 xo-expression2/include/xo/expression2/DLocalSymtab.hpp

diff --git a/xo-expression2/idl/ASymbolTable.json5 b/xo-expression2/idl/ASymbolTable.json5
new file mode 100644
index 00000000..ca10ef91
--- /dev/null
+++ b/xo-expression2/idl/ASymbolTable.json5
@@ -0,0 +1,41 @@
+{
+    mode: "facet",
+    includes: [ ],
+
+    namespace1: "xo",
+    namespace2: "scm",
+    facet: "SymbolTable",
+    detail_subdir: "symtab",
+    brief: "symbol table derived from a set of schematika expressions",
+    using_doxygen: true,
+    doc: [
+        "Map symbols to schematika expression. Output of schematika parser"
+    ],
+    types: [
+        // { name: string, doc: [ string ], definition: string },
+    ],
+    const_methods: [
+        {
+            name: "is_global_symtab",
+            doc: ["true iff this is toplevel (global) symbol table."],
+            return_type: "bool",
+            args: [],
+            const: true,
+            noexcept: true,
+            attributes: [],
+        },
+        {
+            name: "lookup_binding_unint",
+            doc: ["report ingredients needed to address variable at runtime."],
+            return_type: "Binding",
+            args: [
+                {type: "DString*", name: "sym"},
+            ],
+            const: true,
+            noexcept: true,
+            attributes: [],
+        },
+    ],
+    nonconst_methods: [
+    ],
+}
diff --git a/xo-expression2/include/xo/expression2/DLocalSymtab.hpp b/xo-expression2/include/xo/expression2/DLocalSymtab.hpp
new file mode 100644
index 00000000..b8d583bf
--- /dev/null
+++ b/xo-expression2/include/xo/expression2/DLocalSymtab.hpp
@@ -0,0 +1,54 @@
+/** @file DLocalSymtab.hpp
+ *
+ *  @author Roland Conybeare, Jan 2026
+ **/
+
+#pragma once
+
+#include "TypeRef.hpp"
+#include "exprtype.hpp"
+#include <xo/reflect/TaggedPtr.hpp>
+#include <xo/gc/GCObject.hpp>
+
+namespace xo {
+    namespace scm {
+        /** @class DLocalSymtab
+         *  @brief Schematika expression respresenting a literal constant
+         **/
+        struct DLocalSymtab {
+        public:
+            using TaggedPtr = xo::reflect::TaggedPtr;
+            using TypeDescr = xo::reflect::TypeDescr;
+            using AGCObject = xo::mm::AGCObject;
+            using typeseq = xo::reflect::typeseq;
+
+        public:
+            explicit DLocalSymtab(obj<AGCObject> value) noexcept;
+
+            bool is_resolved() const noexcept { return typeref_.is_resolved(); }
+
+            exprtype extype() const noexcept { return exprtype::constant; }
+            TypeDescr value_td() const noexcept { return typeref_.td(); }
+            TaggedPtr value_tp() const noexcept { return TaggedPtr(typeref_.td(), value_.data()); }
+
+            TypeRef typeref() const noexcept { return typeref_; }
+            TypeDescr valuetype() const noexcept { return typeref_.td(); }
+            obj<AGCObject> value() const noexcept { return value_; }
+
+            void assign_valuetype(TypeDescr td) noexcept { typeref_.resolve(td); }
+
+        private:
+            static TypeDescr _lookup_td(typeseq tseq);
+
+        private:
+            /** type for value of this expression
+             *  or unification breadcrumb before unification
+             **/
+            TypeRef typeref_;
+            /** literal value **/
+            obj<AGCObject> value_;
+        };
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/* end DLocalSymtab.hpp */