View Javadoc

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.functions;
22  
23  import org.millscript.commons.util.EList;
24  import org.millscript.millscript.vm.Machine;
25  
26  /**
27   * This is the base class of all mutable list construction functions.
28   */
29  abstract class MutableListFunction extends ListFunction {
30  
31      /**
32       * @see org.millscript.millscript.functions.Function#apply(org.millscript.millscript.vm.Machine, int)
33       */
34      @Override
35      public void apply( final Machine mc, final int nargs ) {
36          EList< Object > list = newEmptyMutableList();
37          initialize( mc, nargs, list );
38          mc.pushObject( list );
39      }
40  
41      /**
42       * Returns the new empty mutable list for this function.
43       *
44       * @return  a new empty mutable List
45       */
46      public abstract EList< Object > newEmptyMutableList();
47  
48      /**
49       * Initialises the specified list with the specified number of arguments
50       * from the machine.
51       *
52       * @param mc    the machine to get arguments from
53       * @param nargs the number of arguments available
54       * @param list  the list to populate with the arguments
55       */
56      private static void initialize( final Machine mc, final int nargs, final EList< Object > list ) {
57          if ( nargs >= 1 ) {
58              Object x = mc.popObject();
59              initialize( mc, nargs - 1, list );
60              list.addLast( x );
61          }
62      }
63  
64  }