new file mode 100644
--- /dev/null
+++ b/src/pt-unop.cc
@@ -0,0 +1,273 @@
+/*
+
+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 (__GNUG__)
+#pragma implementation
+#endif
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "error.h"
+#include "oct-obj.h"
+#include "oct-lvalue.h"
+#include "ov.h"
+#include "pt-unop.h"
+#include "pt-pr-code.h"
+#include "pt-walk.h"
+
+// Prefix expressions.
+
+octave_value_list
+tree_prefix_expression::rvalue (int nargout)
+{
+  octave_value_list retval;
+
+  if (nargout > 1)
+    error ("prefix operator `%s': invalid number of output arguments",
+	   oper () . c_str ());
+  else
+    retval = rvalue ();
+
+  return retval;
+}
+
+octave_value
+tree_prefix_expression::rvalue (void)
+{
+  octave_value retval;
+
+  if (error_state)
+    return retval;
+
+  if (op)
+    {
+      if (etype == unot || etype == uminus)
+	{
+	  octave_value val = op->rvalue ();
+
+	  if (! error_state)
+	    {
+	      if (val.is_defined ())
+		{
+		  if (etype == unot)
+		    retval = val.not ();
+		  else
+		    retval = val.uminus ();
+		}
+	      else
+		error ("argument to prefix operator `%s' undefined",
+		       oper () . c_str ());
+	    }
+	}
+      else if (etype == increment || etype == decrement)
+	{
+	  octave_lvalue ref = op->lvalue ();
+
+	  if (! error_state)
+	    {
+	      if (ref.is_defined ())
+		{
+		  if (etype == increment)
+		    ref.increment ();
+		  else
+		    ref.decrement ();
+
+		  retval = ref.value ();
+		}
+	      else
+		error ("argument to prefix operator `%s' undefined",
+		       oper () . c_str ());
+	    }
+	}
+      else
+	error ("prefix operator %d not implemented", etype);
+    }
+
+  return retval;
+}
+
+void
+tree_prefix_expression::eval_error (void)
+{
+  if (error_state > 0)
+    ::error ("evaluating prefix operator `%s' near line %d, column %d",
+	     oper () . c_str (), line (), column ());
+}
+
+string
+tree_prefix_expression::oper (void) const
+{
+  string retval = "<unknown>";
+
+  switch (etype)
+    {
+    case unot:
+      retval = "!";
+      break;
+
+    case uminus:
+      retval = "-";
+      break;
+
+    case increment:
+      retval = "++";
+      break;
+
+    case decrement:
+      retval = "--";
+      break;
+
+    default:
+      break;
+    }
+
+  return retval;
+}
+
+void
+tree_prefix_expression::accept (tree_walker& tw)
+{
+  tw.visit_prefix_expression (*this);
+}
+
+// Postfix expressions.
+
+octave_value_list
+tree_postfix_expression::rvalue (int nargout)
+{
+  octave_value_list retval;
+
+  if (nargout > 1)
+    error ("postfix operator `%s': invalid number of output arguments",
+	   oper () . c_str ());
+  else
+    retval = rvalue ();
+
+  return retval;
+}
+
+octave_value
+tree_postfix_expression::rvalue (void)
+{
+  octave_value retval;
+
+  if (error_state)
+    return retval;
+
+  if (op)
+    {
+      if (etype == transpose || etype == hermitian)
+	{
+	  octave_value val = op->rvalue ();
+
+	  if (! error_state)
+	    {
+	      if (val.is_defined ())
+		{
+		  if (etype == transpose)
+		    retval = val.transpose ();
+		  else
+		    retval = val.hermitian ();
+		}
+	      else
+		error ("argument to postfix operator `%s' undefined",
+		       oper () . c_str ());
+	    }
+	}
+      else if (etype == increment || etype == decrement)
+	{
+	  octave_lvalue ref = op->lvalue ();
+
+	  if (! error_state)
+	    {
+	      if (ref.is_defined ())
+		{
+		  retval = ref.value ();
+
+		  if (etype == increment)
+		    ref.increment ();
+		  else
+		    ref.decrement ();
+		}
+	      else
+		error ("argument to postfix operator `%s' undefined",
+		       oper () . c_str ());
+	    }
+	}
+      else
+	error ("postfix operator %d not implemented", etype);
+    }
+
+  return retval;
+}
+
+void
+tree_postfix_expression::eval_error (void)
+{
+  if (error_state > 0)
+    ::error ("evaluating postfix operator `%s' near line %d, column %d",
+	     oper () . c_str (), line (), column ());
+}
+
+string
+tree_postfix_expression::oper (void) const
+{
+  string retval = "<unknown>";
+
+  switch (etype)
+    {
+    case transpose:
+      retval = ".'";
+      break;
+
+    case hermitian:
+      retval = "'";
+      break;
+
+    case increment:
+      retval = "++";
+      break;
+
+    case decrement:
+      retval = "--";
+      break;
+
+    default:
+      break;
+    }
+
+  return retval;
+}
+
+void
+tree_postfix_expression::accept (tree_walker& tw)
+{
+  tw.visit_postfix_expression (*this);
+}
+
+/*
+;;; Local Variables: ***
+;;; mode: C++ ***
+;;; End: ***
+*/