--- a/src/symtab.h
+++ b/src/symtab.h
@@ -42,7 +42,7 @@
 class tree;
 class tree_fvc;
 class tree_builtin;
-class octave_value;
+class tree_constant;
 class tree_function;
 
 class string_vector;
@@ -62,7 +62,7 @@
 public:
 
   symbol_def (void);
-  symbol_def (octave_value *t);
+  symbol_def (tree_constant *t);
   symbol_def (tree_builtin *t, unsigned fcn_type = 0);
   symbol_def (tree_function *t, unsigned fcn_type = 0);
 
@@ -76,8 +76,9 @@
   int is_user_function (void) const;
   int is_builtin_variable (void) const;
   int is_builtin_function (void) const;
+  int is_map_element (const string& elts) const;
 
-  void define (octave_value *t);
+  void define (tree_constant *t);
   void define (tree_builtin *t, unsigned fcn_type = 0);
   void define (tree_function *t, unsigned fcn_type = 0);
 
@@ -146,6 +147,7 @@
   int is_variable (void) const;
   int is_user_variable (void) const;
   int is_builtin_variable (void) const;
+  int is_map_element (const string& elts) const;
 
   unsigned type (void) const;
 
@@ -159,11 +161,12 @@
 
   void set_sv_function (sv_Function f);
 
-  int define (octave_value *t);
+  int define (tree_constant *t);
+  int define (const octave_value& v);
   int define (tree_builtin *t, int text_fcn = 0);
   int define (tree_function *t, int text_fcn = 0);
-  int define_as_fcn (octave_value *t);
-  int define_builtin_var (octave_value *t);
+  int define_as_fcn (const octave_value& v);
+  int define_builtin_var (const octave_value& v);
 
   void document (const string& h);
 
@@ -177,6 +180,9 @@
   void mark_as_linked_to_global (void);
   int is_linked_to_global (void) const;
 
+  octave_value variable_value (void) const;
+  octave_value& variable_reference (void);
+
   symbol_record *next (void) const;
 
   void chain (symbol_record *s);
@@ -230,7 +236,7 @@
   int is_eternal (void) const;
   int hides_fcn (void) const;
   int hides_builtin (void) const;
-  string type_as_string (void) const;
+  string type_name (void) const;
   int is_function (void) const;
   int rows (void) const;
   int columns (void) const;