new file mode 100644
--- /dev/null
+++ b/src/pt-assign.h
@@ -0,0 +1,153 @@
+/*
+
+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_assign_h)
+#define octave_tree_assign_h 1
+
+#if defined (__GNUG__)
+#pragma interface
+#endif
+
+#include <string>
+
+class ostream;
+
+class tree_argument_list;
+class tree_walker;
+
+class octave_value;
+class octave_value_list;
+class octave_lvalue;
+
+#include "ov.h"
+#include "pt-exp.h"
+
+// Simple assignment expressions.
+
+class
+tree_simple_assignment : public tree_expression
+{
+public:
+
+  tree_simple_assignment (bool plhs = false, int l = -1, int c = -1,
+			  octave_value::assign_op t = octave_value::asn_eq)
+    : tree_expression (l, c), lhs (0), rhs (0), preserve (plhs), etype (t) { }
+
+  tree_simple_assignment (tree_expression *le, tree_expression *re,
+			  bool plhs = false, int l = -1, int c = -1,
+			  octave_value::assign_op t = octave_value::asn_eq)
+    : tree_expression (l, c), lhs (le), rhs (re), preserve (plhs),
+      etype (t) { }
+
+  ~tree_simple_assignment (void);
+
+  bool rvalue_ok (void) const
+    { return true; }
+
+  octave_value rvalue (void);
+
+  octave_value_list rvalue (int nargout);
+
+  bool is_assignment_expression (void) const
+    { return true; }
+
+  void eval_error (void);
+
+  string oper (void) const;
+
+  tree_expression *left_hand_side (void) { return lhs; }
+
+  tree_expression *right_hand_side (void) { return rhs; }
+
+  void accept (tree_walker& tw);
+
+private:
+
+  void do_assign (octave_lvalue& ult, const octave_value_list& args,
+		  const octave_value& rhs_val);
+
+  void do_assign (octave_lvalue& ult, const octave_value& rhs_val);
+
+  // The left hand side of the assignment.
+  tree_expression *lhs;
+
+  // The right hand side of the assignment.
+  tree_expression *rhs;
+
+  // True if we should not delete the lhs.
+  bool preserve;
+
+  // True if this is an assignment to the built-in variable ans.
+  bool ans_ass;
+
+  // The type of the expression.
+  octave_value::assign_op etype;
+};
+
+// Multi-valued assignment expressions.
+
+class
+tree_multi_assignment : public tree_expression
+{
+public:
+
+  tree_multi_assignment (bool plhs = false, int l = -1, int c = -1)
+    : tree_expression (l, c), preserve (plhs), lhs (0), rhs (0) { }
+
+  tree_multi_assignment (tree_argument_list *lst, tree_expression *r,
+			 bool plhs = false, int l = -1, int c = -1)
+    : tree_expression (l, c), preserve (plhs), lhs (lst), rhs (r) { }
+
+  ~tree_multi_assignment (void);
+
+  bool is_assignment_expression (void) const
+    { return true; }
+
+  bool rvalue_ok (void) const
+    { return true; }
+
+  octave_value rvalue (void);
+
+  octave_value_list rvalue (int nargout);
+
+  void eval_error (void);
+
+  tree_argument_list *left_hand_side (void) { return lhs; }
+
+  tree_expression *right_hand_side (void) { return rhs; }
+
+  void accept (tree_walker& tw);
+
+private:
+
+  bool preserve;
+  tree_argument_list *lhs;
+  tree_expression *rhs;
+};
+
+#endif
+
+/*
+;;; Local Variables: ***
+;;; mode: C++ ***
+;;; End: ***
+*/