--- a/src/pt-misc.h
+++ b/src/pt-misc.h
@@ -27,152 +27,16 @@
 #pragma interface
 #endif
 
-class ostream;
-
-class string_vector;
-
-class octave_value_list;
-class octave_value;
-class tree_command;
-class tree_expression;
-class tree_simple_assignment;
-class tree_index_expression;
-class tree_identifier;
-class symbol_record;
-class symbol_table;
-
-class tree_statement;
-class tree_statement_list;
-class tree_argument_list;
-class tree_parameter_list;
-class tree_return_list;
-class tree_va_return_list;
-class tree_decl_elt;
-class tree_decl_init_list;
-class tree_if_clause;
-class tree_if_command_list;
-class tree_switch_case;
-class tree_switch_case_list;
-
-class tree_walker;
-
 #include <SLList.h>
 
-// A statement is either a command to execute or an expression to
-// evaluate.
-
-class
-tree_statement
-{
-public:
-
-  tree_statement (void)
-    : cmd (0), expr (0), print_flag (true) { }
-
-  tree_statement (tree_command *c)
-    : cmd (c), expr (0), print_flag (true) { }
-
-  tree_statement (tree_expression *e)
-    : cmd (0), expr (e), print_flag (true) { }
-
-  ~tree_statement (void);
-
-  void set_print_flag (bool print)
-    { print_flag = print; }
-
-  bool is_command (void)
-    { return cmd != 0; }
-
-  bool is_expression (void)
-    { return expr != 0; }
-
-  int line (void);
-  int column (void);
-
-  void maybe_echo_code (bool in_function_body);
-
-  bool print_result (void) { return print_flag; }
-
-  tree_command *command (void) { return cmd; }
-
-  octave_value_list eval (bool silent, int nargout, bool in_function_body);
-
-  tree_expression *expression (void) { return expr; }
-
-  void accept (tree_walker& tw);
-
-private:
-
-  // Only one of cmd or expr can be valid at once.
-
-  // Command to execute.
-  tree_command *cmd;
-
-  // Expression to evaluate.
-  tree_expression *expr;
-
-  // Print result of eval for this command?
-  bool print_flag;
-};
+class octave_value;
+class octave_value_list;
 
-// A list of statements to evaluate.
-
-class
-tree_statement_list : public SLList<tree_statement *>
-{
-public:
-
-  tree_statement_list (void)
-    : SLList<tree_statement *> (), function_body (false) { }
-
-  tree_statement_list (tree_statement *s)
-    : SLList<tree_statement *> (), function_body (false) { append (s); }
-
-  ~tree_statement_list (void)
-    {
-      while (! empty ())
-	{
-	  tree_statement *t = remove_front ();
-	  delete t;
-	}
-    }
-
-  void mark_as_function_body (void) { function_body = true; }
-
-  octave_value_list eval (bool silent = false, int nargout = 0);
-
-  void accept (tree_walker& tw);
+class tree_identifier;
+class tree_index_expression;
+class tree_va_return_list;
 
-private:
-
-  // Does this list of statements make up the body of a function?
-  bool function_body;
-};
-
-// Argument lists.  Used to hold the list of expressions that are the
-// arguments in a function call or index expression.
-
-class
-tree_argument_list : public SLList<tree_expression *>
-{
-public:
-
-  tree_argument_list (void)
-    : SLList<tree_expression *> () { }
-
-  tree_argument_list (tree_expression *t)
-    : SLList<tree_expression *> () { append (t); }
-
-  ~tree_argument_list (void);
-
-  bool all_elements_are_constant (void) const;
-
-  octave_value_list convert_to_const_vector (void);
-
-  string_vector get_arg_names (void) const;
-
-  void accept (tree_walker& tw);
-};
+class tree_walker;
 
 // Parameter lists.  Used to hold the list of input and output
 // parameters in a function definition.  Elements are identifiers
@@ -249,186 +113,6 @@
   ~tree_va_return_list (void) { }
 };
 
-// List of expressions that make up a declaration statement.
-
-class
-tree_decl_elt
-{
-public:
-
-  typedef void (*eval_fcn) (tree_decl_elt &, bool);
-
-  tree_decl_elt (tree_identifier *i = 0, tree_expression *e = 0)
-    : id (i), expr (e) { }
-
-  ~tree_decl_elt (void);
-
-  void eval (void);
-
-  tree_identifier *ident (void) { return id; }
-
-  tree_expression *expression (void) { return expr; }
-
-  void accept (tree_walker& tw);
-
-private:
-
-  // An identifier to tag with the declared property.
-  tree_identifier *id;
-
-  // An initializer expression (may be zero);
-  tree_expression *expr;
-};
-
-class
-tree_decl_init_list : public SLList<tree_decl_elt *>
-{
-public:
-
-  tree_decl_init_list (void)
-    : SLList<tree_decl_elt *> () { }
-
-  tree_decl_init_list (tree_decl_elt *t)
-    : SLList<tree_decl_elt *> () { append (t); }
-
-  ~tree_decl_init_list (void)
-    {
-      while (! empty ())
-	{
-	  tree_decl_elt *t = remove_front ();
-	  delete t;
-	}
-    }
-
-  void eval (tree_decl_elt::eval_fcn, bool);
-
-  void accept (tree_walker& tw);
-};
-
-class
-tree_if_clause
-{
-public:
-
-  tree_if_clause (void) : expr (0), list (0) { }
-
-  tree_if_clause (tree_statement_list *l)
-    : expr (0), list (l) { }
-
-  tree_if_clause (tree_expression *e, tree_statement_list *l)
-    : expr (e), list (l) { }
-
-  ~tree_if_clause (void);
-
-  bool is_else_clause (void)
-    { return ! expr; }
-
-  int eval (void);
-
-  tree_expression *condition (void) { return expr; }
-
-  tree_statement_list *commands (void) { return list; }
-
-  void accept (tree_walker& tw);
-
-private:
-
-  // The condition to test.
-  tree_expression *expr;
-
-  // The list of statements to evaluate if expr is true.
-  tree_statement_list *list;
-};
-
-class
-tree_if_command_list : public SLList<tree_if_clause *>
-{
-public:
-
-  tree_if_command_list (void)
-    : SLList<tree_if_clause *> () { }
-
-  tree_if_command_list (tree_if_clause *t)
-    : SLList<tree_if_clause *> () { append (t); }
-
-  ~tree_if_command_list (void)
-    {
-      while (! empty ())
-	{
-	  tree_if_clause *t = remove_front ();
-	  delete t;
-	}
-    }
-
-  void eval (void);
-
-  void accept (tree_walker& tw);
-};
-
-class
-tree_switch_case
-{
-public:
-
-  tree_switch_case (void) : label (0), list (0) { }
-
-  tree_switch_case (tree_statement_list *l)
-    : label (0), list (l) { }
-
-  tree_switch_case (tree_expression *e, tree_statement_list *l)
-    : label (e), list (l) { }
-
-  ~tree_switch_case (void);
-
-  bool is_default_case (void)
-    { return ! label; }
-
-  bool label_matches (const octave_value& val);
-
-  int eval (const octave_value& val);
-
-  void eval_error (void);
-
-  tree_expression *case_label (void) { return label; }
-
-  tree_statement_list *commands (void) { return list; }
-
-  void accept (tree_walker& tw);
-
-private:
-
-  // The case label.
-  tree_expression *label;
-
-  // The list of statements to evaluate if the label matches.
-  tree_statement_list *list;
-};
-
-class
-tree_switch_case_list : public SLList<tree_switch_case *>
-{
-public:
-
-  tree_switch_case_list (void)
-    : SLList<tree_switch_case *> () { }
-
-  tree_switch_case_list (tree_switch_case *t)
-    : SLList<tree_switch_case *> () { append (t); }
-
-  ~tree_switch_case_list (void)
-    {
-      while (! empty ())
-	{
-	  tree_switch_case *t = remove_front ();
-	  delete t;
-	}
-    }
-
-  void eval (const octave_value& val);
-
-  void accept (tree_walker& tw);
-};
-
 #endif
 
 /*