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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.expr.LocalIdent;
24  import org.millscript.millscript.functions.ClosureFunction;
25  import org.millscript.millscript.functions.LambdaFunction;
26  import org.millscript.millscript.vm.Machine;
27  import org.millscript.millscript.vm.Ref;
28  
29  /**
30   * This class represents an action that makes a closure function.
31   *
32   * @see org.millscript.millscript.expr.LambdaExpr
33   * @todo    this class could really use a better description
34   */
35  public final class MakeClosureAction extends Action {
36  
37      /**
38       * The function to make a closure with.
39       */
40      private final LambdaFunction lambda;
41  
42      /**
43       * The set of local idents to save.
44       */
45      private final LocalIdent[] outerIds;
46  
47      /**
48       * The set of references used by the local idents.
49       */
50      private final Ref[] outerRefs;
51  
52      /**
53       * Constructs a new make closure action, to make a closure function from
54       * the specified function and local variables.
55       *
56       * @param a the local variables that need to be saved
57       * @param b the function to make a closure with
58       */
59      public MakeClosureAction( final LocalIdent[] a, final LambdaFunction b ) {
60          outerIds = a;
61          lambda = b;
62          int numOuters = a.length;
63          outerRefs = new Ref[ numOuters ];
64          for ( int i = 0; i < numOuters; i++ ) {
65              outerRefs[ i ] = outerIds[ i ].getRef();
66          }
67      }
68  
69      /**
70       * @see org.millscript.millscript.action.Action#action(org.millscript.millscript.vm.Machine)
71       */
72      @Override
73      public void action( final Machine mc ) {
74          final int numOuters = outerRefs.length;
75          final Object[] outerVals = new Object[ numOuters ];
76          for ( int i = 0; i < numOuters; i++ ) {
77              outerVals[ i ] = outerRefs[ i ].value;
78          }
79          mc.pushObject( new ClosureFunction( outerVals, outerRefs, outerIds, lambda ) );
80      }
81  
82  }