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1   ////////////////////////////////////////////////////////////////////////////////
2   // MillScript: an Open Spice interpreter and batch website creation tool
3   // Copyright (C) 2001-2004 Open World Ltd
4   //
5   // This file is part of MillScript.
6   //
7   // MillScript is free software; you can redistribute it and/or modify it under
8   // the terms of the GNU General Public License as published by the Free
9   // Software Foundation; either version 2 of the License, or (at your option)
10  // any later version.
11  //
12  // MillScript is distributed in the hope that it will be useful, but WITHOUT
13  // ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14  // FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
15  // more details.
16  //
17  // You should have received a copy of the GNU General Public License along with
18  // MillScript; if not, write to the Free Software Foundation, Inc., 59 Temple
19  // Place, Suite 330, Boston, MA  02111-1307  USA
20  ////////////////////////////////////////////////////////////////////////////////
21  package org.millscript.millscript.action;
22  
23  import org.millscript.millscript.vm.Machine;
24  
25  /**
26   * This class is the base of all binary actions, i.e. those that operate on two
27   * values.
28   */
29  public abstract class BinaryOpAction extends Action {
30  
31      /**
32       * The action for the left hand side of the binary operation.
33       */
34      private final Action lhs;
35  
36      /**
37       * The action for the right hand side of the binary operation.
38       */
39      private final Action rhs;
40  
41      /**
42       * Constructs a new binary action, with the specified left and right hand
43       * side actions.
44       *
45       * @param a the left hand side action
46       * @param b the right hand side action
47       */
48      protected BinaryOpAction( final Action a, final Action b ) {
49          this.lhs = a;
50          this.rhs = b;
51      }
52  
53      /**
54       * Performs this binary action on the specified left and right hand side
55       * values.
56       *
57       * @param x the left hand side value
58       * @param y the right hand side value
59       * @return  the result of this binary action on the left and right hand
60       * side values
61       */
62      public abstract Object perform( final Object x, final Object y );
63  
64      /**
65       * @see org.millscript.millscript.action.Action#action(org.millscript.millscript.vm.Machine)
66       */
67      @Override
68      public final void action( final Machine mc ) {
69          mc.pushObject( perform( lhs.act1( mc ), rhs.act1( mc ) ) );
70      }
71  
72  }