--- a/src/variables.h
+++ b/src/variables.h
@@ -24,6 +24,7 @@
 #define octave_variables_h 1
 
 class octave_function;
+class octave_user_function;
 class symbol_record;
 class symbol_table;
 
@@ -40,6 +41,8 @@
 #include "ov-builtin.h"
 #include "symtab.h"
 
+extern bool at_top_level (void);
+
 extern void initialize_symbol_tables (void);
 
 extern bool is_builtin_variable (const std::string&);
@@ -83,6 +86,9 @@
 extern octave_function *
 lookup_function (const std::string& nm);
 
+extern octave_user_function *
+lookup_user_function (const std::string& nm);
+
 extern octave_value get_global_value (const std::string& nm);
 
 extern void set_global_value (const std::string& nm, const octave_value& val);