From 0e2ddcf839a1e5abbd81d282666ceadf987369af Mon Sep 17 00:00:00 2001
From: Roland Conybeare <rconybeare@gmail.com>
Date: Wed, 26 Nov 2025 20:15:03 -0500
Subject: [PATCH] xo-interpreter: Object->TaggedPtr conversion (prep for
 primitives)

---
 .../xo/expression/FunctionExprInterface.hpp   | 12 +++----
 include/xo/expression/Lambda.hpp              |  4 +--
 .../xo/expression/PrimitiveExprInterface.hpp  |  6 ++--
 .../xo/expression/ProcedureExprInterface.hpp  | 33 +++++++++++++++++++
 src/expression/Lambda.cpp                     |  2 +-
 5 files changed, 45 insertions(+), 12 deletions(-)
 create mode 100644 include/xo/expression/ProcedureExprInterface.hpp

diff --git a/include/xo/expression/FunctionExprInterface.hpp b/include/xo/expression/FunctionExprInterface.hpp
index 62756654..340d3f11 100644
--- a/include/xo/expression/FunctionExprInterface.hpp
+++ b/include/xo/expression/FunctionExprInterface.hpp
@@ -1,4 +1,4 @@
-/** @file FunctionInterface.hpp
+/** @file ProcedureExprInterface.hpp
  *
  *  Author: Roland Conybeare
  **/
@@ -10,14 +10,14 @@
 
 namespace xo {
     namespace scm {
-        class FunctionExprInterface : public Expression {
+        class ProcedureExprInterface : public Expression {
         public:
-            FunctionExprInterface(exprtype extype, TypeDescr fn_type)
+            ProcedureExprInterface(exprtype extype, TypeDescr fn_type)
                 : Expression(extype, fn_type) {}
 
             /** downcast from Expression **/
-            static bp<FunctionExprInterface> from(bp<Expression> x) {
-                return bp<FunctionExprInterface>::from(x);
+            static bp<ProcedureExprInterface> from(bp<Expression> x) {
+                return bp<ProcedureExprInterface>::from(x);
             }
 
             virtual const std::string & name() const = 0;
@@ -30,4 +30,4 @@ namespace xo {
     } /*namespace scm*/
 } /*namespace xo*/
 
-/** end FunctionInterface.hpp **/
+/** end ProcedureExprInterface.hpp **/
diff --git a/include/xo/expression/Lambda.hpp b/include/xo/expression/Lambda.hpp
index e4d24cd6..e5b3aeb1 100644
--- a/include/xo/expression/Lambda.hpp
+++ b/include/xo/expression/Lambda.hpp
@@ -6,7 +6,7 @@
 #pragma once
 
 #include "Expression.hpp"
-#include "FunctionExprInterface.hpp"
+#include "ProcedureExprInterface.hpp"
 #include "Variable.hpp"
 #include "LocalSymtab.hpp"
 #include <map>
@@ -19,7 +19,7 @@ namespace xo {
          *  @brief abstract syntax tree for a function definition
          *
          **/
-        class Lambda : public FunctionExprInterface {
+        class Lambda : public ProcedureExprInterface {
         public:
             /**
              *  @p name.  Name for this lambda -- must be unique
diff --git a/include/xo/expression/PrimitiveExprInterface.hpp b/include/xo/expression/PrimitiveExprInterface.hpp
index 1011e5dc..9db7be14 100644
--- a/include/xo/expression/PrimitiveExprInterface.hpp
+++ b/include/xo/expression/PrimitiveExprInterface.hpp
@@ -5,19 +5,19 @@
 
 #pragma once
 
-#include "FunctionExprInterface.hpp"
+#include "ProcedureExprInterface.hpp"
 #include "llvmintrinsic.hpp"
 #include <type_traits>
 
 namespace xo {
     namespace scm {
-        class PrimitiveExprInterface : public FunctionExprInterface {
+        class PrimitiveExprInterface : public ProcedureExprInterface {
         public:
             using void_function_type = void (*)();
 
         public:
             explicit PrimitiveExprInterface(TypeDescr fn_type)
-                : FunctionExprInterface(exprtype::primitive, fn_type) {}
+                : ProcedureExprInterface(exprtype::primitive, fn_type) {}
 
             /** downcast from Expression **/
             static bp<PrimitiveExprInterface> from(bp<Expression> x) {
diff --git a/include/xo/expression/ProcedureExprInterface.hpp b/include/xo/expression/ProcedureExprInterface.hpp
new file mode 100644
index 00000000..62acf21a
--- /dev/null
+++ b/include/xo/expression/ProcedureExprInterface.hpp
@@ -0,0 +1,33 @@
+/** @file FunctionExprInterface.hpp
+ *
+ *  Author: Roland Conybeare
+ **/
+
+#pragma once
+
+#include "Expression.hpp"
+//#include <cstdint>
+
+namespace xo {
+    namespace scm {
+        class ProcedureExprInterface : public Expression {
+        public:
+            ProcedureExprInterface(exprtype extype, TypeDescr fn_type)
+                : Expression(extype, fn_type) {}
+
+            /** downcast from Expression **/
+            static bp<ProcedureExprInterface> from(bp<Expression> x) {
+                return bp<ProcedureExprInterface>::from(x);
+            }
+
+            virtual const std::string & name() const = 0;
+            virtual int n_arg() const = 0; // { return this->value_td()->n_fn_arg(); }
+            virtual TypeDescr fn_retval() const = 0; // { return this->value_td()->fn_retval(); }
+            virtual TypeDescr fn_arg(uint32_t i) const = 0; // { return this->value_td()->fn_arg(i); }
+
+        private:
+        }; /*FunctionInterface*/
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/** end FunctionExprInterface.hpp **/
diff --git a/src/expression/Lambda.cpp b/src/expression/Lambda.cpp
index d944b690..0196f52e 100644
--- a/src/expression/Lambda.cpp
+++ b/src/expression/Lambda.cpp
@@ -259,7 +259,7 @@ namespace xo {
                        TypeDescr lambda_td,
                        const rp<LocalSymtab> & local_env,
                        const rp<Expression> & body)
-            : FunctionExprInterface(exprtype::lambda, lambda_td),
+            : ProcedureExprInterface(exprtype::lambda, lambda_td),
               name_{name},
               body_{body},
               local_env_{local_env}