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.functions.Function;
24 import org.millscript.millscript.functions.SpiceClassConstructorFunction;
25 import org.millscript.millscript.tools.CastLibrary;
26 import org.millscript.millscript.vm.Machine;
27
28 /**
29 * This class implements the action for a <code>init</code> expression. This
30 * behaves much like a normal apply action, but it examines the function action
31 * to see if it is a constructor function and if so it extracts the underlying
32 * initialiser and applies that.
33 *
34 * @see org.millscript.millscript.expr.InitExpr
35 * @see org.millscript.millscript.syntax.InitSyntax
36 */
37 public final class InitAction extends Action {
38
39 /**
40 * The constructor function action.
41 */
42 private Action constructorAction;
43
44 /**
45 * The constructor arguments action.
46 */
47 private Action argsAction;
48
49 /**
50 * Constructs a new <code>init</code> action to run the supplied
51 * initialiser action.
52 *
53 * @param c the initialiser action
54 */
55 public InitAction( final Action ca, final Action aa ) {
56 this.argsAction = aa;
57 this.constructorAction = ca;
58 }
59
60 /**
61 * @see org.millscript.millscript.action.Action#action(org.millscript.millscript.vm.Machine)
62 */
63 @Override
64 public void action( final Machine mc ) {
65 // Store the number of values on the stack, before generating the
66 // arguments
67 int before = mc.getCount();
68 // Generate the arguments for the function
69 argsAction.act( mc );
70 // Store the number of values on the stack, after generating the
71 // arguments
72 int after = mc.getCount();
73 // Perform the constructor function action
74 this.constructorAction.act( mc );
75 // Get the class constructor function off the stack
76 final SpiceClassConstructorFunction constructorFunction = CastLibrary.toSpiceClassConstructorFunction( mc.popObject() );
77 // Get the initialiser out of the constructor function
78 final Function initialiserFunction = constructorFunction.getInitialiserFunction();
79 // Now apply the initialiser function
80 // Record the function entry
81 mc.enterFunction( initialiserFunction );
82 // Apply the function, telling it how many arguments it has
83 initialiserFunction.apply( mc, after - before );
84 // Record the function's exit
85 mc.exitFunction( initialiserFunction );
86 }
87
88 }