new file mode 100644
--- /dev/null
+++ b/src/pt-unop.h
@@ -0,0 +1,157 @@
+/*
+
+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_unop_h)
+#define octave_tree_unop_h 1
+
+#if defined (__GNUG__)
+#pragma interface
+#endif
+
+#include <string>
+
+class tree_walker;
+
+class octave_value;
+class octave_value_list;
+class octave_lvalue;
+
+#include "pt-exp.h"
+
+// Unary expressions.
+
+class
+tree_unary_expression : public tree_expression
+{
+public:
+
+  tree_unary_expression (int l = -1, int c = -1)
+    : tree_expression (l, c), op (0)  { }
+
+  tree_unary_expression (tree_expression *e, int l = -1, int c = -1)
+    : tree_expression (l, c), op (e) { }
+
+  ~tree_unary_expression (void) { delete op; }
+
+  tree_expression *operand (void) { return op; }
+
+protected:
+
+  // The operand for the expression.
+  tree_expression *op;
+};
+
+// Prefix expressions.
+
+class
+tree_prefix_expression : public tree_unary_expression
+{
+public:
+
+  enum type
+    {
+      unknown,
+      unot,
+      uminus,
+      increment,
+      decrement
+    };
+
+  tree_prefix_expression (int l = -1, int c = -1)
+    : tree_unary_expression (l, c), etype (unknown) { }
+
+  tree_prefix_expression (type t = unknown, tree_expression *e,
+			  int l = -1, int c = -1)
+    : tree_unary_expression (e, l, c), etype (t) { }
+
+  ~tree_prefix_expression (void) { }
+
+  bool rvalue_ok (void) const
+    { return true; }
+
+  octave_value rvalue (void);
+
+  octave_value_list rvalue (int nargou);
+
+  void eval_error (void);
+
+  string oper (void) const;
+
+  void accept (tree_walker& tw);
+
+private:
+
+  // The type of the expression.
+  type etype;
+};
+
+// Postfix expressions.
+
+class
+tree_postfix_expression : public tree_unary_expression
+{
+public:
+
+  enum type
+    {
+      unknown,
+      hermitian,
+      transpose,
+      increment,
+      decrement
+    };
+
+  tree_postfix_expression (int l = -1, int c = -1)
+    : tree_unary_expression (l, c), etype (unknown) { }
+
+  tree_postfix_expression (type t = unknown, tree_expression *e,
+			   int l = -1, int c = -1)
+    : tree_unary_expression (e, l, c), etype (t) { }
+
+  ~tree_postfix_expression (void) { }
+
+  bool rvalue_ok (void) const
+    { return true; }
+
+  octave_value rvalue (void);
+
+  octave_value_list rvalue (int nargout);
+
+  void eval_error (void);
+
+  string oper (void) const;
+
+  void accept (tree_walker& tw);
+
+private:
+
+  // The type of the expression.
+  type etype;
+};
+
+#endif
+
+/*
+;;; Local Variables: ***
+;;; mode: C++ ***
+;;; End: ***
+*/