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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 represents a simple conditional action for an <code>if</code>
27   * statement. This class handles the case where there is a predicate action and
28   * an action to execute if the predicate evaluates to <code>true</code>.
29   *
30   * @see org.millscript.millscript.syntax.ConditionalSyntax
31   * @see org.millscript.millscript.expr.If2Expr
32   */
33  public final class If2Action extends Action {
34  
35      /**
36       * The predicate action, which is evaluated to a <code>true</code> or
37       * <code>false</code> value.
38       */
39      private Action pred;
40  
41      /**
42       * The action to be evaluated if the predicate action evaluates to
43       * <code>true</code>.
44       */
45      private Action ifso;
46  
47      /**
48       * Constructs a new if action for the specified predicate and body actions.
49       *
50       * @param a the predicate action
51       * @param b the body action
52       */
53      public If2Action( final Action a, final Action b ) {
54          this.pred = a;
55          this.ifso = b;
56      }
57  
58      /**
59       * @see org.millscript.millscript.action.Action#action(org.millscript.millscript.vm.Machine)
60       */
61      @Override
62      public void action( final Machine mc ) {
63          if ( pred.predAct( mc ) ) {
64              ifso.act( mc );
65          }
66      }
67  
68  }