--- a/src/pt-const.h
+++ b/src/pt-const.h
@@ -24,10 +24,6 @@
 #if !defined (octave_tree_const_h)
 #define octave_tree_const_h 1
 
-#if defined (__GNUG__)
-#pragma interface
-#endif
-
 #include <iostream.h>
 
 #include <stdlib.h>

--- a/src/pt-exp-base.cc
+++ b/src/pt-exp-base.cc
@@ -25,10 +25,6 @@
 #include "config.h"
 #endif
 
-#if defined (__GNUG__)
-#pragma implementation
-#endif
-
 #include <sys/types.h>
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>

--- a/src/pt-exp-base.h
+++ b/src/pt-exp-base.h
@@ -24,10 +24,6 @@
 #if !defined (octave_tree_expr_h)
 #define octave_tree_expr_h 1
 
-#if defined (__GNUG__)
-#pragma interface
-#endif
-
 #include <time.h>
 #include <stdio.h>
 #include <iostream.h>
@@ -117,7 +113,7 @@
       etype = unknown;
     }
 
-  ~tree_expression (void) { }
+  virtual ~tree_expression (void) { }
 
   virtual int is_multi_val_ret_expression (void) const
     { return 0; }
@@ -268,8 +264,6 @@
       maybe_do_ans_assign = 0;
     }
 
-  ~tree_identifier (void) { }
-
   int is_identifier (void) const
     { return 1; }
 
@@ -777,8 +771,6 @@
   tree_builtin (int i_max, int o_max, Octave_builtin_fcn f,
 		const char *nm = 0);
 
-  ~tree_builtin (void) { }
-
 //  int is_builtin (void) const;
 
   int is_mapper_function (void) const
@@ -843,8 +835,6 @@
 	 cmd_list = cl;
        }
 
-  ~tree_function (void) { }
-
 //  tree_function *define (tree_statement_list *t);
   tree_function *define_param_list (tree_parameter_list *t);
   tree_function *define_ret_list (tree_parameter_list *t);

--- a/src/pt-plot.cc
+++ b/src/pt-plot.cc
@@ -25,10 +25,6 @@
 #include "config.h"
 #endif
 
-#if defined (__GNUG__)
-#pragma implementation
-#endif
-
 #include <sys/types.h>
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>
@@ -725,6 +721,44 @@
     }
 }
 
+subplot::subplot (void)
+{
+  plot_data = 0;
+  using = 0;
+  title = 0;
+  style = 0;
+}
+
+subplot::subplot (tree_expression *data)
+{
+  plot_data = data;
+  using = 0;
+  title = 0;
+  style = 0;
+}
+
+subplot::subplot (subplot_using *u, tree_expression *t, subplot_style *s)
+{
+  plot_data = 0;
+  using = u;
+  title = t;
+  style = s;
+}
+
+subplot::~subplot (void)
+{
+  delete plot_data;
+  delete using;
+  delete title;
+  delete style;
+}
+
+void
+subplot::set_data (tree_expression *data)
+{
+  plot_data = data;
+}
+
 tree_constant
 subplot::extract_plot_data (int ndim, tree_constant& data)
 {
@@ -900,7 +934,6 @@
     style->print_code (os);
 }
 
-int
 subplot_list::print (int ndim, ostrstream& plot_buf)
 {
   int status = 0;

--- a/src/pt-plot.h
+++ b/src/pt-plot.h
@@ -24,10 +24,6 @@
 #if !defined (octave_tree_plot_h)
 #define octave_tree_plot_h 1
 
-#if defined (__GNUG__)
-#pragma interface
-#endif
-
 #include <iostream.h>
 
 class tree_command;
@@ -163,48 +159,20 @@
 subplot : public tree_print_code
 {
 public:
-  subplot (void)
-    {
-      plot_data = 0;
-      using = 0;
-      title = 0;
-      style = 0;
-    }
-
-  subplot (tree_expression *data)
-    {
-      plot_data = data;
-      using = 0;
-      title = 0;
-      style = 0;
-    }
+  subplot (void);
+  subplot (tree_expression *data);
+  subplot (subplot_using *u, tree_expression *t, subplot_style *s);
 
-  subplot (subplot_using *u, tree_expression *t,
-		subplot_style *s)
-    {
-      plot_data = 0;
-      using = u;
-      title = t;
-      style = s;
-    }
+  ~subplot (void);
 
-  ~subplot (void)
-    {
-      delete plot_data;
-      delete using;
-      delete title;
-      delete style;
-    }
-
-  void set_data (tree_expression *data)
-    { plot_data = data; }
-
-  int print (int ndim, ostrstream& plot_buf);
+  void set_data (tree_expression *data);
 
   tree_constant extract_plot_data (int ndim, tree_constant& data);
 
   int handle_plot_data (int ndim, ostrstream& plot_buf);
 
+  int print (int ndim, ostrstream& plot_buf);
+
   void print_code (ostream& os);
 
 private:
@@ -219,6 +187,7 @@
 {
  public:
   subplot_list (void) : SLList<subplot *> () { }
+
   subplot_list (subplot *t) : SLList<subplot *> ()
     { append (t); }