--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/pt.h	Fri May 16 07:05:49 1997 +0000
@@ -0,0 +1,75 @@
+/*
+
+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_h)
+#define octave_tree_h 1
+
+#if defined (__GNUG__)
+#pragma interface
+#endif
+
+class tree_walker;
+
+// Base class for the parse tree.
+
+class
+tree
+{
+public:
+
+  tree (int l = -1, int c = -1)
+    {
+      line_num = l;
+      column_num = c;
+    }
+
+  virtual ~tree (void) { }
+
+  virtual int line (void) const
+    { return line_num; }
+
+  virtual int column (void) const
+    { return column_num; }
+
+  virtual void accept (tree_walker& tw) = 0;
+
+private:
+
+  // The input line and column where we found the text that was
+  // eventually converted to this tree node.
+  int line_num;
+  int column_num;
+
+  // No copying!
+
+  tree (const tree&);
+
+  tree& operator = (const tree&);
+};
+
+#endif
+
+/*
+;;; Local Variables: ***
+;;; mode: C++ ***
+;;; End: ***
+*/