diff --git a/include/mes/builtins.h b/include/mes/builtins.h
index 47ff1eee..891a5711 100644
--- a/include/mes/builtins.h
+++ b/include/mes/builtins.h
@@ -175,8 +175,8 @@ struct scm *variable_ref (struct scm *var);
 struct scm *flat_variable_ref (struct scm *var);
 struct scm *variable_set_x (struct scm *var, struct scm *value);
 struct scm *variable_bound_p (struct scm *var);
-struct scm *lookup_variable (struct scm *name, struct scm *define_p);
-struct scm *lookup_ref (struct scm *name);
+struct scm *lookup_handle (struct scm *name, struct scm* define_p);
+struct scm *lookup_ref (struct scm *name, struct scm* bound_p);
 /* src/vector.c */
 struct scm *make_vector (struct scm *x);
 struct scm *vector_length (struct scm *x);
diff --git a/include/mes/constants.h b/include/mes/constants.h
index 3f86c6cf..c030a7be 100644
--- a/include/mes/constants.h
+++ b/include/mes/constants.h
@@ -73,6 +73,12 @@
 // CONSTANT FRAME_PROCEDURE 4
 #define FRAME_PROCEDURE 4
 
+// CONSTANT MODULE_DEFINES = 3
+#define MODULE_DEFINES 3
+
+// CONSTANT MODULE_USES = 4
+#define MODULE_USES 4
+
 // CONSTANT STDIN 0
 // CONSTANT STDOUT 1
 // CONSTANT STDERR 2
diff --git a/include/mes/mes.h b/include/mes/mes.h
index 0529f74d..29202e39 100644
--- a/include/mes/mes.h
+++ b/include/mes/mes.h
@@ -127,13 +127,16 @@ struct scm *apply_builtin1 (struct scm *fn, struct scm *x);
 struct scm *apply_builtin2 (struct scm *fn, struct scm *x, struct scm *y);
 struct scm *apply_builtin3 (struct scm *fn, struct scm *x, struct scm *y, struct scm *z);
 struct scm *builtin_name (struct scm *builtin);
+struct scm *cell_ref (struct scm *cell, long index);
 struct scm *cstring_to_list (char const *s);
 struct scm *cstring_to_symbol (char const *s);
-struct scm *cell_ref (struct scm *cell, long index);
+struct scm *current_module ();
 struct scm *fdisplay_ (struct scm *, int, int);
+struct scm *handle_set_x (struct scm *name, struct scm *value);
 struct scm *init_symbols ();
 struct scm *init_time (struct scm *a);
-struct scm *lookup_variable_ (char const* name);
+struct scm *lookup_handle (struct scm *name, struct scm *define_p);
+struct scm *lookup_ref_ (char const *name);
 struct scm *make_builtin_type ();
 struct scm *make_bytes (char const *s, size_t length);
 struct scm *make_cell (long type, struct scm *car, struct scm *cdr);
@@ -152,6 +155,9 @@ struct scm *make_string0 (char const *s);
 struct scm *make_string_port (struct scm *x);
 struct scm *make_vector_ (long k, struct scm *e);
 struct scm *mes_builtins (struct scm *a);
+struct scm *module_defines (struct scm *module);
+struct scm *module_handle (struct scm *module, struct scm *name);
+struct scm *module_variable (struct scm *module, struct scm *name);
 struct scm *push_cc (struct scm *p1, struct scm *p2, struct scm *a, struct scm *c);
 struct scm *set_x (struct scm *x, struct scm *e);
 struct scm *struct_ref_ (struct scm *x, long i);
diff --git a/mes/module/mes/boot-0.scm b/mes/module/mes/boot-0.scm
index 535501c6..ce8202b6 100644
--- a/mes/module/mes/boot-0.scm
+++ b/mes/module/mes/boot-0.scm
@@ -30,7 +30,7 @@
 (define mes %version)
 
 (define (defined? x)
-  (lookup-variable x #f))
+  (lookup-handle x #f))
 
 (define (cond-expand-expander clauses)
   (if (defined? (car (car clauses)))
diff --git a/mes/module/mes/boot-00.scm b/mes/module/mes/boot-00.scm
index 7203b231..e98ea6e0 100644
--- a/mes/module/mes/boot-00.scm
+++ b/mes/module/mes/boot-00.scm
@@ -20,7 +20,7 @@
 (define mes %version)
 
 (define (defined? x)
-  (lookup-variable x #f))
+  (lookup-handle x #f))
 
 (define (cond-expand-expander clauses)
   (if (defined? (car (car clauses)))
diff --git a/mes/module/mes/boot-01.scm b/mes/module/mes/boot-01.scm
index 5e1bfa72..8e0a9406 100644
--- a/mes/module/mes/boot-01.scm
+++ b/mes/module/mes/boot-01.scm
@@ -20,7 +20,7 @@
 (define mes %version)
 
 (define (defined? x)
-  (lookup-variable x #f))
+  (lookup-handle x #f))
 
 (define (cond-expand-expander clauses)
   (if (defined? (car (car clauses)))
diff --git a/mes/module/mes/boot-02.scm b/mes/module/mes/boot-02.scm
index 4a5a0356..dbc5f731 100644
--- a/mes/module/mes/boot-02.scm
+++ b/mes/module/mes/boot-02.scm
@@ -30,7 +30,7 @@
 (define mes %version)
 
 (define (defined? x)
-  (lookup-variable x #f))
+  (lookup-handle x #f))
 
 (define (cond-expand-expander clauses)
   (if (defined? (car (car clauses)))
diff --git a/mes/module/mes/boot-03.scm b/mes/module/mes/boot-03.scm
index 843dfc1a..6b80c05a 100644
--- a/mes/module/mes/boot-03.scm
+++ b/mes/module/mes/boot-03.scm
@@ -30,7 +30,7 @@
 (define mes %version)
 
 (define (defined? x)
-  (lookup-variable x #f))
+  (lookup-handle x #f))
 
 (define (cond-expand-expander clauses)
   (if (defined? (car (car clauses)))
diff --git a/mes/module/mes/boot-module.scm b/mes/module/mes/boot-module.scm
index c0ae542d..cd8bfde6 100644
--- a/mes/module/mes/boot-module.scm
+++ b/mes/module/mes/boot-module.scm
@@ -149,20 +149,18 @@
 
 (define guile:current-module (make-fluid #f))
 
-(define lookup-global #f)
-(define (global-lookup-function name define?)
-  ;; (if define? (module-make-local-var! (guile:current-module) name)
-  ;;     (module-variable (guile:current-module) name))
-  '("boe")
-  )
+(define module-system-booted? #f)
+(define *current-module* #f)
+
 (define (set-current-module m)
   (display "set-current-module: name=")
   (display (module-name m))
   (display "\n")
   (let ((o (guile:current-module)))
     (guile:current-module m)
-    ;; (unless o
-    ;;   (set! lookup-global global-lookup-function))
+    (set! *current-module* m)
+    (unless o
+      (set! module-system-booted? #t))
     o))
 
 (define (make-hook . n)
@@ -1232,7 +1230,14 @@
     (if (and variable (variable-bound? variable))
 	(variable-ref variable)
 	(if (null? rest)
-	    (error "No variable named" name 'in module)
+	    (begin
+              (when variable
+                (display "Variable's value is undefined: " (current-error-port))
+                (display name (current-error-port))
+                (display ": " (current-error-port))
+                (write variable (current-error-port))
+                (display "\n" (current-error-port)))
+              (error "No variable named" name 'in module))
 	    (car rest)			; default value
 	    ))))
 
@@ -2725,13 +2730,25 @@
 (define-module (guile-user) #:use-module (boo))
 
 (display "\nnow in guile-user\n")
-(display "ZEE:")
-;;(display ((module-ref (guile:current-module) 'ZEE-MODULE)))
-;;(display (module-ref (resolve-module '(boo)) 'ZEE-MODULE))
+(display "keil-user: ")
+(write  *current-module*)
+(display "\n")
+(display "ZEE-MODULE:")
+(display ((module-ref (guile:current-module) 'ZEE-MODULE)))
+;; (display (module-ref (resolve-module '(boo)) 'ZEE-MODULE))
 ;; (display "\n")
-(ZEE-MODULE)
+;; (ZEE-MODULE)
 (display "\n")
 (display "bah: ")
-;;(display (module-ref (guile:current-module) 'bah))
-(display bah)
+(display (module-ref (guile:current-module) 'bah))
+;;(display bah)
 (display "\n")
+
+
+;; (display "===> ZEE\n")
+;; (display ZEE-MODULE)
+;; (display "\n")
+
+;; (display "===> (ZEE)\n")
+;; (display (ZEE-MODULE))
+;; (display "\n")
diff --git a/scaffold/boot/53-closure-display.scm b/scaffold/boot/53-closure-display.scm
index 9ba02224..0d02cd47 100644
--- a/scaffold/boot/53-closure-display.scm
+++ b/scaffold/boot/53-closure-display.scm
@@ -28,7 +28,7 @@
     (if (null? lst) (list)
         (cons (f (car lst)) (map f (cdr lst)))))
   (define (closure x)
-    (map car (cdr (core:cdr (core:car (core:cdr (cdr (lookup-variable 'x #f))))))))))
+    (map car (cdr (core:cdr (core:car (core:cdr (cdr (lookup-handle 'x #f))))))))))
 
 (define (x t) #t)
 (define (xx x1 x2)
diff --git a/scaffold/boot/60-let-syntax-expanded.scm b/scaffold/boot/60-let-syntax-expanded.scm
index 64f85c2e..5ed3d34f 100644
--- a/scaffold/boot/60-let-syntax-expanded.scm
+++ b/scaffold/boot/60-let-syntax-expanded.scm
@@ -20,7 +20,7 @@
 (define mes %version)
 
 (define (defined? x)
-  (lookup-variable x #f))
+  (lookup-handle x #f))
 
 (define (cond-expand-expander clauses)
   (if (defined? (car (car clauses)))
diff --git a/src/builtins.c b/src/builtins.c
index 0f11d3a5..cfae324b 100644
--- a/src/builtins.c
+++ b/src/builtins.c
@@ -285,8 +285,8 @@ mes_builtins (struct scm *a)            /*:((internal)) */
   a = init_builtin (builtin_type, "flat-variable-ref", 1, &flat_variable_ref, a);
   a = init_builtin (builtin_type, "variable-set!", 2, &variable_set_x, a);
   a = init_builtin (builtin_type, "variable-bound?", 1, &variable_bound_p, a);
-  a = init_builtin (builtin_type, "lookup-variable", 2, &lookup_variable, a);
-  a = init_builtin (builtin_type, "lookup-ref", 1, &lookup_ref, a);
+  a = init_builtin (builtin_type, "lookup-handle", 2, &lookup_handle, a);
+  a = init_builtin (builtin_type, "lookup-ref", 2, &lookup_ref, a);
   /* src/vector.c */
   a = init_builtin (builtin_type, "make-vector", -1, &make_vector, a);
   a = init_builtin (builtin_type, "vector-length", 1, &vector_length, a);
diff --git a/src/core.c b/src/core.c
index 05d32775..1f3ae36f 100644
--- a/src/core.c
+++ b/src/core.c
@@ -149,9 +149,9 @@ struct scm *
 error (struct scm *key, struct scm *x)
 {
 #if !__MESC_MES__ && !__M2_PLANET__
-  struct scm *throw = lookup_variable (cell_symbol_throw, cell_f);
+  struct scm *throw = lookup_ref (cell_symbol_throw, cell_f);
   if (throw != cell_f)
-    return apply (throw->cdr, cons (key, cons (x, cell_nil)), R0);
+    return apply (throw, cons (key, cons (x, cell_nil)), R0);
 #endif
   display_error_ (key);
   eputs (": ");
diff --git a/src/eval-apply.c b/src/eval-apply.c
index f1d4216b..0eb73155 100644
--- a/src/eval-apply.c
+++ b/src/eval-apply.c
@@ -120,8 +120,8 @@ set_x (struct scm *x, struct scm *e)        /*:((internal)) */
     p = x->variable;
   else
     {
-      p = lookup_variable (x, cell_f);
-      if (p == cell_f || p-> cdr == cell_undefined)
+      p = lookup_handle (x, cell_f);
+      if (p == cell_f || p->cdr == cell_undefined)
         error (cell_symbol_unbound_variable, x);
     }
   if (p->type != TPAIR)
@@ -261,7 +261,7 @@ expand_variable_ (struct scm *x, struct scm *formals, int top_p)        /*:((int
                    && a != cell_symbol_primitive_load
                    && formal_p (x->car, formals) == 0)
             {
-              struct scm *v = lookup_variable (a, cell_f);
+              struct scm *v = lookup_handle (a, cell_f);
               if (v != cell_f)
                 x->car = make_variable (v);
             }
@@ -319,7 +319,7 @@ eval_apply ()
   struct scm *args;
   struct scm *body;
   struct scm *cl;
-  struct scm *entry;
+  struct scm *handle;
   struct scm *expanders;
   struct scm *formals;
   struct scm *input;
@@ -626,15 +626,15 @@ eval:
                       name = name->car;
                     if (macro_p != 0)
                       {
-                        entry = cell_f;
+                        handle = cell_f;
                         /* FIXME: dead code; no tests
-                        entry = assq (name, g_macros);
-                        if (entry == cell_f)
+                        handle = assq (name, g_macros);
+                        if (handle == cell_f)
                         */
-                        macro_set_x (name, entry);
+                        macro_set_x (name, handle);
                       }
                     else
-                      entry = lookup_variable (name, cell_t);
+                      lookup_handle (name, cell_t);
                   }
                 R2 = R1;
                 aa = R1->cdr->car;
@@ -662,14 +662,24 @@ eval:
                   name = name->car;
                 if (macro_p != 0)
                   {
-                    entry = macro_get_handle (name);
+                    handle = macro_get_handle (name);
                     R1 = make_macro (name, R1);
-                    set_cdr_x (entry, R1);
+                    set_cdr_x (handle, R1);
                   }
                 else if (global_p != 0)
                   {
-                    entry = lookup_variable (name, cell_f);
-                    set_cdr_x (entry, R1);
+                    handle = lookup_handle (name, cell_f);
+                    if (g_debug > 0)
+                      {
+                        eputs ("global set: ");
+                        write_error_ (name);
+                        eputs ("\n");
+                      }
+#if 0
+                    set_cdr_x (handle, R1);
+#else
+                    handle_set_x (handle, R1);
+#endif
                   }
                 else
                   {
@@ -681,11 +691,11 @@ eval:
                         eputs ("\n");
                       }
 #endif
-                    entry = cons (name, R1);
-                    aa = cons (entry, cell_nil);
+                    handle = cons (name, R1);
+                    aa = cons (handle, cell_nil);
                     set_cdr_x (aa, cdr (R0));
                     set_cdr_x (R0, aa);
-                    cl = lookup_variable (cell_closure, cell_f);
+                    cl = lookup_handle (cell_closure, cell_f);
                     set_cdr_x (cl, aa);
                   }
                 R1 = cell_unspecified;
@@ -710,7 +720,7 @@ eval:
         goto vm_return;
       if (R1 == cell_symbol_call_with_current_continuation)
         goto vm_return;
-      R1 = lookup_ref (R1);
+      R1 = lookup_ref (R1, cell_t);
       goto vm_return;
     }
   else if (t == TVARIABLE)
@@ -783,15 +793,15 @@ macro_expand:
           macro = macro_get_handle (cell_symbol_portable_macro_expand);
           if (macro != cell_f)
             {
-              expanders = lookup_ref (cell_symbol_sc_expander_alist);
-              if (expanders != cell_f)
+              expanders = lookup_ref (cell_symbol_sc_expander_alist, cell_f);
+              if (expanders != cell_undefined)
                 {
                   macro = assq (R1->car, expanders);
                   if (macro != cell_f)
                     {
-                      sc_expand = lookup_ref (cell_symbol_macro_expand);
+                      sc_expand = lookup_ref (cell_symbol_macro_expand, cell_f);
                       R2 = R1;
-                      if (sc_expand != cell_undefined && sc_expand != cell_f)
+                      if (sc_expand != cell_undefined && sc_expand != cell_undefined)
                         {
                           R1 = cons (sc_expand, cons (R1, cell_nil));
                           goto apply;
diff --git a/src/module.c b/src/module.c
index 2c8dfc1c..a742fc06 100644
--- a/src/module.c
+++ b/src/module.c
@@ -39,72 +39,89 @@ initial_module ()
   return M0;
 }
 
-// struct scm *
-// module_define_x (struct scm *module, struct scm *name, struct scm *value)
-// {
-//   return hashq_set_x (M0, name, value);
-// }
-
-// struct scm *
-// scm_module_lookup_closure (struct scm *module)
-// {
-//   if (module == cell_f)
-//     return cell_f;
-//   else
-//     return struct_ref (module, MODULE_EVAL_CLOSURE);
-// }
-
-// struct scm *
-// scm_current_module_lookup_closure ()
-// {
-//   if (scm_module_system_booted_p)
-//     return scm_module_lookup_closure (scm_current_module ());
-//   return cell_f;
-// }
-
-// struct scm *
-// scm_eval_closure_lookup (struct scm *eclo, struct scm *name, struct scm *define_p)
-// {
-//   struct scm *module = eclo;
-//   if (define_p == cell_f)
-//     return module_variable (module, name);
-//   else
-//     {
-// #if 0
-//       if (struct scm *_EVAL_CLOSURE_INTERFACE_P (eclo))
-//         return struct cell_f;
-// #endif
-//       return apply (module_make_local_var_x_var, cons (module, cons (name, cell_nil)));
-//     }
-// }
+struct scm *
+current_module ()     /*:((internal)) */
+{
+  /*  struct scm *booted_p = hashq_get_handle_ (M0, cstring_to_symbol ("module-system-booted?"), cell_f);
+  if (booted_p->type == TPAIR && booted_p->cdr != cell_f)
+  {
+  */
+  struct scm *module = hashq_get_handle_ (M0, cstring_to_symbol ("*current-module*"), cell_f);
+  if (module->type == TPAIR && module->cdr != cell_f)
+    return module->cdr;
+  /*
+     }
+  */
+  return M0;
+}
 
 struct scm *
-module_variable (struct scm *module, struct scm *name)
+module_defines (struct scm *module)     /*:((internal)) */
 {
-  /* 1. Check module obarray */
-  struct scm *a = struct_ref_ (module, MODULE_OBARRAY);
-  struct scm *b = scm_hashq_ref (a, name, cell_f);
-  if (b != cell_f)
-    return b;
+  if (module != cell_f && module != M0)
+    return struct_ref_ (module, MODULE_DEFINES);
+  return M0;
+}
 
-  // /* 2. Custom binder */
-  // struct scm *binder = struct_ref (module, MODULE_BINDER);
-  // if (binder != cell_f)
-  //   {
-  //     b = apply (binder->cdr, (cons (module, cons (name, cons (cell_f, cell_nil)))), cell_f);
-  //     if (b != cell_f)
-  //       return b;
-  //   }
+struct scm *
+module_define_x (struct scm *module, struct scm *name, struct scm *value)
+{
+  struct scm *table = module_defines (module);
+  return hashq_set_x (table, name, value);
+}
 
-  /* 3. Search the use list */
-  struct scm *uses = struct_ref (module, MODULE_USES);
-  while (uses->type == TPAIR)
+struct scm *
+module_handle (struct scm *module, struct scm *name)     /*:((internal)) */
+{
+  /* 1. Check module defines.  */
+  struct scm *table = module_defines (module);
+  if (g_debug > 0)
     {
-      b = module_variable (uses->car, name);
+      eputs ("module_handle:");
+      eputs (" name = ");
+      write_error_ (name);
+      // eputs (" defines = ");
+      // write_error_ (table);
+      eputs ("\n");
+    }
+
+  struct scm *handle = hashq_get_handle_ (table, name, cell_f);
+  if (handle != cell_f)
+    return handle;
+
+  /* 2. Custom binder.  */
+  /*
+  struct scm *binder = struct_ref (module, MODULE_BINDER);
+  if (binder != cell_f)
+    {
+      b = apply (binder->cdr, (cons (module, cons (name, cons (cell_f, cell_nil)))), cell_f);
       if (b != cell_f)
         return b;
+    }
+  */
+
+  /* 3. Search the use list.  */
+  struct scm *uses = struct_ref_ (module, MODULE_USES);
+  while (uses->type == TPAIR)
+    {
+      handle = module_handle (uses->car, name);
+      if (handle != cell_f)
+        return handle;
       uses = uses->cdr;
     }
 
+  /* 4. Hack for Mes: always look in M0. */
+  handle = hashq_get_handle_ (M0, name, cell_f);
+
+  return handle;
+}
+
+/* NOT USED? */
+struct scm *
+module_variable (struct scm *module, struct scm *name)
+{
+  struct scm *handle = module_handle (module, name);
+  if (handle != cell_f)
+    return handle->cdr;
   return cell_f;
 }
diff --git a/src/variable.c b/src/variable.c
index 1f74248c..21bc0c24 100644
--- a/src/variable.c
+++ b/src/variable.c
@@ -45,9 +45,32 @@ flat_variable_ref (struct scm *var)
 struct scm *
 variable_set_x (struct scm *var, struct scm *value)
 {
+#if 0
   assert_variable (1, var);
   var->variable = value;
   return cell_unspecified;
+#else
+    if (g_debug > 0)
+    {
+      eputs ("variable-set!");
+      write_error_ (var);
+      eputs ("\n");
+    }
+  if (var->type == TPAIR)
+    {
+      struct scm *x = var->cdr;
+      if (x->type == TVARIABLE)
+        x->variable = value;
+      else
+        //set_cdr_x (var, value);
+        var->cdr = value;
+    }
+  else if (var->type == TVARIABLE)
+    var->variable = value;
+  else
+    assert_variable (1, var);
+  return cell_unspecified;
+#endif
 }
 
 struct scm *
@@ -61,30 +84,65 @@ variable_bound_p (struct scm *var)
 }
 
 struct scm *
-lookup_variable (struct scm *name, struct scm *define_p)
+handle_set_x (struct scm *handle, struct scm *value)
+{
+#if 0
+  struct scm *x = handle->cdr;
+  if (x->type == TVARIABLE)
+    x->variable = value;
+  else
+    handle->cdr = value;
+  return cell_unspecified;
+#else
+  if (g_debug > 0)
+    {
+      eputs ("variable-set!");
+      write_error_ (handle);
+      eputs ("\n");
+    }
+  if (handle->type == TPAIR)
+    {
+      struct scm *x = handle->cdr;
+      if (x->type == TVARIABLE)
+        x->variable = value;
+      else
+        //set_cdr_x (handle, value);
+        handle->cdr = value;
+    }
+  else if (handle->type == TVARIABLE)
+    handle->variable = value;
+  else
+    assert_variable (1, handle);
+  return cell_unspecified;
+#endif
+}
+
+/*
+  GUILE has `proc': scm_current_module -> scm_module_lookup_closure -> standard-eval-closure:
+
+  BUT: define-p: module-make-local-var!, !define-p: module-variable
+
+ */
+struct scm *
+lookup_handle (struct scm *name, struct scm *define_p)
 {
   struct scm *handle = handle = assq (name, R0);
 
   if (handle == cell_f)
     {
-      struct scm *lookup = hashq_get_handle_ (M0, cstring_to_symbol ("lookup-global"), cell_f);
-      if (lookup != cell_f && lookup->cdr != cell_f)
+      struct scm *module = current_module ();
+      if (define_p == cell_f)
         {
-          eputs ("lookup? ");
-          display_error_ (lookup);
-          eputs (" ...  \n");
-          handle = apply (lookup->cdr, cons (name, cons (define_p, cell_nil)), R0);
-          eputs ("lookup: ");
-          display_error_ (name);
-          eputs (" => ");
-          write_error_ (handle);
-          if (handle != cell_f)
-            handle = cons (name, name->variable);
+          if (module == M0)
+            handle = hashq_get_handle_ (M0, name, cell_f);
+          else
+            handle = module_handle (module, name);
         }
       else
         {
-          handle = hashq_get_handle_ (M0, name, cell_f);
-          if (handle == cell_f && define_p == cell_t)
+          struct scm *table = module_defines (module);
+          handle = hashq_get_handle_ (table, name, cell_f);
+          if (handle == cell_f)
             {
               if (g_debug > 0)
                 {
@@ -92,7 +150,15 @@ lookup_variable (struct scm *name, struct scm *define_p)
                   write_error_ (name);
                   eputs ("\n");
                 }
-              handle = hashq_set_handle_x (M0, name, cell_f);
+              handle = hashq_set_handle_x (table, name, cell_f);
+            }
+          else if (handle->cdr == cell_undefined)
+            {
+              eputs ("lookup + define: ");
+              write_error_ (name);
+              eputs ("  found: ");
+              write_error_ (handle);
+              eputs ("\n");
             }
         }
     }
@@ -101,16 +167,20 @@ lookup_variable (struct scm *name, struct scm *define_p)
 }
 
 struct scm *
-lookup_variable_ (char const* name)
+lookup_ref (struct scm *name, struct scm *bound_p)
 {
-  return lookup_variable (cstring_to_symbol (name), cell_f);
+  struct scm *handle = lookup_handle (name, cell_f);
+  if (handle == cell_f)
+    {
+      if (bound_p == cell_t)
+        error (cell_symbol_unbound_variable, name);
+      return cell_undefined;
+    }
+  return handle->cdr;
 }
 
 struct scm *
-lookup_ref (struct scm *name)
+lookup_ref_ (char const *name)
 {
-  struct scm *x = lookup_variable (name, cell_f);
-  if (x == cell_f)
-    error (cell_symbol_unbound_variable, name);
-  return x->cdr;
+  return lookup_ref (cstring_to_symbol (name), cell_f);
 }