xo-interpreter2 stack: scaffold DClosure, DLocalEnv [WIP]

src/interpreter2/CMakeLists.txt

@@ -17,6 +17,10 @@ set(SELF_SRCS
     IPrintable_DVsmApplyFrame.cpp
 
     VsmInstr.cpp
+
+    DClosure.cpp
+    DLocalEnv.cpp
+
     #IExpression_Any.cpp
     )
 

src/interpreter2/DClosure.cpp

@@ -0,0 +1,29 @@
+/** @file DClosure.cpp
+ *
+ *  @author Roland Conybeare, Feb 2026
+ **/
+
+#include "DClosure.hpp"
+
+namespace xo {
+    namespace scm {
+
+        DClosure::DClosure(const DLambdaExpr * lm,
+                           const DLocalEnv * env)
+        : lambda_{lm}, env_{env}
+        {}
+
+        DClosure *
+        DClosure::make(obj<AAllocator> mm,
+                       const DLambdaExpr * lm,
+                       const DLocalEnv * env)
+        {
+            void * mem = mm.alloc_for<DClosure>();
+
+            return new (mem) DClosure(lm, env);
+        }
+
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/* end DClosure.cpp */

src/interpreter2/DLocalEnv.cpp

@@ -0,0 +1,92 @@
+/** @file DLocalEnv.cpp
+ *
+ *  @author Roland Conybeare, Feb 2026
+ **/
+
+#include "DLocalEnv.hpp"
+#include <xo/reflectutil/typeseq.hpp>
+
+namespace xo {
+    using xo::mm::AGCObject;
+    using xo::reflect::typeseq;
+
+    namespace scm {
+
+        DLocalEnv::DLocalEnv(DLocalEnv * parent,
+                             DLocalSymtab * symtab,
+                             DArray * args)
+        : parent_{parent},
+          symtab_{symtab},
+          args_{args}
+        {}
+
+        DLocalEnv *
+        DLocalEnv::_make_empty(obj<AAllocator> mm,
+                               DLocalEnv * parent,
+                               DLocalSymtab * symtab,
+                               DArray * args)
+        {
+            assert(symtab);
+
+            void * mem = mm.alloc_for<DLocalEnv>();
+
+            return new (mem) DLocalEnv(parent, symtab, args);
+        }
+
+        obj<AGCObject>
+        DLocalEnv::lookup_value(Binding ix) const noexcept
+        {
+            assert(!ix.is_global());
+
+            const DLocalEnv * env = this;
+
+            for (auto i = ix.i_link(); i > 0; --i) {
+                env = env->parent();
+            }
+
+            if (env) {
+                auto j = ix.j_slot();
+
+                if (j < static_cast<decltype(j)>(env->size())) {
+                    return (*(env->args_))[j];
+                } else {
+                    assert(false);
+                }
+            } else {
+                assert(false);
+            }
+
+            /* something terribly wrong if control here */
+            return obj<AGCObject>();
+        }
+
+        void
+        DLocalEnv::assign_value(Binding ix, obj<AGCObject> x)
+        {
+            assert(!ix.is_global());
+
+            const DLocalEnv * env = this;
+
+            for (auto i = ix.i_link(); i > 0; --i) {
+                env = env->parent();
+            }
+
+            if (env) {
+                auto j = ix.j_slot();
+
+                if (j < static_cast<decltype(j)>(env->size())) {
+                    (*(env->args_))[j] = x;
+                } else {
+                    assert(false);
+                }
+            } else {
+                assert(false);
+            }
+
+            /* something terribly wrong if control here */
+        }
+
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/* end DLocalEnv.cpp */