new file mode 100644
--- /dev/null
+++ b/src/pt-stmt.h
@@ -0,0 +1,136 @@
+/*
+
+Copyright (C) 1996, 1997 John W. Eaton
+
+This file is part of Octave.
+
+Octave is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by the
+Free Software Foundation; either version 2, or (at your option) any
+later version.
+
+Octave is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with Octave; see the file COPYING.  If not, write to the Free
+Software Foundation, 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+
+*/
+
+#if !defined (octave_tree_stmt_h)
+#define octave_tree_stmt_h 1
+
+#if defined (__GNUG__)
+#pragma interface
+#endif
+
+#include <SLList.h>
+
+class octave_value_list;
+
+class tree_command;
+class tree_expression;
+
+class tree_walker;
+
+// 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;
+};
+
+// 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);
+
+private:
+
+  // Does this list of statements make up the body of a function?
+  bool function_body;
+};
+
+#endif
+
+/*
+;;; Local Variables: ***
+;;; mode: C++ ***
+;;; End: ***
+*/