xo-expression2: + DApplyExpr [WIP]. Builds, not used or tested

include/xo/expression2/DApplyExpr.hpp

@@ -0,0 +1,64 @@
+/** @file DApplyExpr.hpp
+ *
+ *  @author Roland Conybeare, Jan 2026
+ **/
+
+#pragma once
+
+#include "Expression.hpp"
+#include "TypeRef.hpp"
+#include "exprtype.hpp"
+#include <xo/object2/DArray.hpp>
+#include <xo/reflect/TypeDescr.hpp>
+#include <xo/indentlog/print/pretty.hpp>
+
+namespace xo {
+    namespace scm {
+
+        /** @class DApplyExpr
+         *  @brief syntax for a procedure/function call
+         **/
+        class DApplyExpr {
+        public:
+            using TypeDescr = xo::reflect::TypeDescr;
+            using ppindentinfo = xo::print::ppindentinfo;
+            using size_type = std::size_t;
+
+        public:
+
+            obj<AExpression>  fn() const noexcept { return fn_; }
+            const DArray * args() const noexcept { return args_; }
+
+            size_type n_arg() const noexcept { return args_->size(); }
+            obj<AExpression> arg(size_type i) const;
+
+            /** @defgroup scm-applyexpr-expression-facet **/
+            ///@{
+
+            exprtype extype() const noexcept { return exprtype::apply; }
+            TypeRef typeref() const noexcept { return typeref_; }
+            TypeDescr valuetype() const noexcept { return typeref_.td(); }
+            void assign_valuetype(TypeDescr td) noexcept;
+
+            ///@}
+            /** @defgroup scm-applyexpr-printable-facet **/
+            ///@{
+
+            bool pretty(const ppindentinfo & ppii) const;
+
+            ///@}
+
+        private:
+            /** expression value always has type consistent
+             *  with this description
+             **/
+            TypeRef typeref_;
+            /** expression for function/procedure to invoke **/
+            obj<AExpression> fn_;
+            /** expression for each argument vector **/
+            const DArray * args_;
+        };
+    }
+}
+
+/* end DApplyExpr.hpp */

include/xo/expression2/DVariable.hpp

@@ -15,7 +15,7 @@
 namespace xo {
     namespace scm {
 
-        /** @class DVariable*
+        /** @class DVariable
          *  @brief syntax for a variable reference
          **/
         class DVariable {

include/xo/expression2/exprtype.hpp

@@ -29,8 +29,10 @@ namespace xo {
 #ifdef NOT_YET
             /** variable assignment **/
             assign,
+#endif
             /** function call **/
             apply,
+#ifdef NOT_YET
             /** function definition **/
             lambda,
 #endif
@@ -61,7 +63,9 @@ namespace xo {
             case exprtype::define: return "define";
 #ifdef NOT_YET
             case exprtype::assign: return "assign";
+#endif
             case exprtype::apply: return "apply";
+#ifdef NOT_YET
             case exprtype::lambda: return "lambda";
             case exprtype::variable: return "variable";
             case exprtype::ifexpr: return "if_expr";