new file mode 100644
--- /dev/null
+++ b/src/pt-select.h
@@ -0,0 +1,233 @@
+/*
+
+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_select_h)
+#define octave_tree_select_h 1
+
+#if defined (__GNUG__)
+#pragma interface
+#endif
+
+#include <SLList.h>
+
+class expression;
+class tree_statement_list;
+
+class tree_walker;
+
+#include "pt-cmd.h"
+
+// If.
+
+class
+tree_if_clause
+{
+public:
+
+  tree_if_clause (void)
+    : expr (0), list (0) { }
+
+  tree_if_clause (tree_statement_list *l)
+    : expr (0), list (l) { }
+
+  tree_if_clause (tree_expression *e, tree_statement_list *l)
+    : expr (e), list (l) { }
+
+  ~tree_if_clause (void);
+
+  bool is_else_clause (void)
+    { return ! expr; }
+
+  int eval (void);
+
+  tree_expression *condition (void) { return expr; }
+
+  tree_statement_list *commands (void) { return list; }
+
+  void accept (tree_walker& tw);
+
+private:
+
+  // The condition to test.
+  tree_expression *expr;
+
+  // The list of statements to evaluate if expr is true.
+  tree_statement_list *list;
+};
+
+class
+tree_if_command_list : public SLList<tree_if_clause *>
+{
+public:
+
+  tree_if_command_list (void)
+    : SLList<tree_if_clause *> () { }
+
+  tree_if_command_list (tree_if_clause *t)
+    : SLList<tree_if_clause *> () { append (t); }
+
+  ~tree_if_command_list (void)
+    {
+      while (! empty ())
+	{
+	  tree_if_clause *t = remove_front ();
+	  delete t;
+	}
+    }
+
+  void eval (void);
+
+  void accept (tree_walker& tw);
+};
+
+class
+tree_if_command : public tree_command
+{
+public:
+
+  tree_if_command (int l = -1, int c = -1)
+    : tree_command (l, c), list (0) { }
+
+  tree_if_command (tree_if_command_list *lst, int l = -1, int c = -1)
+    : tree_command (l, c), list (lst) { }
+
+  ~tree_if_command (void);
+
+  void eval (void);
+
+  tree_if_command_list *cmd_list (void) { return list; }
+
+  void accept (tree_walker& tw);
+
+private:
+
+  // List of if commands (if, elseif, elseif, ... else, endif)
+  tree_if_command_list *list;
+};
+
+// Switch.
+
+class
+tree_switch_case
+{
+public:
+
+  tree_switch_case (void)
+    : label (0), list (0) { }
+
+  tree_switch_case (tree_statement_list *l)
+    : label (0), list (l) { }
+
+  tree_switch_case (tree_expression *e, tree_statement_list *l)
+    : label (e), list (l) { }
+
+  ~tree_switch_case (void);
+
+  bool is_default_case (void)
+    { return ! label; }
+
+  bool label_matches (const octave_value& val);
+
+  int eval (const octave_value& val);
+
+  void eval_error (void);
+
+  tree_expression *case_label (void) { return label; }
+
+  tree_statement_list *commands (void) { return list; }
+
+  void accept (tree_walker& tw);
+
+private:
+
+  // The case label.
+  tree_expression *label;
+
+  // The list of statements to evaluate if the label matches.
+  tree_statement_list *list;
+};
+
+class
+tree_switch_case_list : public SLList<tree_switch_case *>
+{
+public:
+
+  tree_switch_case_list (void)
+    : SLList<tree_switch_case *> () { }
+
+  tree_switch_case_list (tree_switch_case *t)
+    : SLList<tree_switch_case *> () { append (t); }
+
+  ~tree_switch_case_list (void)
+    {
+      while (! empty ())
+	{
+	  tree_switch_case *t = remove_front ();
+	  delete t;
+	}
+    }
+
+  void eval (const octave_value& val);
+
+  void accept (tree_walker& tw);
+};
+
+class
+tree_switch_command : public tree_command
+{
+public:
+
+  tree_switch_command (int l = -1, int c = -1)
+    : tree_command (l, c), expr (0), list (0) { }
+
+  tree_switch_command (tree_expression *e, tree_switch_case_list *lst,
+		       int l = -1, int c = -1)
+    : tree_command (l, c), expr (e), list (lst) { }
+
+  ~tree_switch_command (void);
+
+  void eval (void);
+
+  void eval_error (void);
+
+  tree_expression *switch_value (void) { return expr; }
+
+  tree_switch_case_list *case_list (void) { return list; }
+
+  void accept (tree_walker& tw);
+
+private:
+
+  // Value on which to switch.
+  tree_expression *expr;
+
+  // List of cases (case 1, case 2, ..., default)
+  tree_switch_case_list *list;
+};
+
+#endif
+
+/*
+;;; Local Variables: ***
+;;; mode: C++ ***
+;;; End: ***
+*/