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.vm.Machine;
25
26 /**
27 * This class implements the action for a function application updater
28 * expression.
29 *
30 * @see org.millscript.millscript.expr.ApplyUpdaterExpr
31 * @see org.millscript.millscript.syntax.AssignSyntax
32 * @see org.millscript.millscript.syntax.ParenSyntax
33 */
34 public final class ApplyUpdaterAction extends Action {
35
36 /**
37 * The action generating the function to apply and update.
38 */
39 private Action fun;
40
41 /**
42 * The action for the arguments to the function.
43 */
44 private Action args;
45
46 /**
47 * The action for the values to update the function with.
48 */
49 private Action uargs;
50
51 /**
52 * Constructs a new function application updater action, with the specified
53 * actions for the function, it's arguments and update values.
54 *
55 * @param f the action generating the function to apply
56 * @param a the action for the arguments to the function
57 * @param u the action for the values to update the function with
58 */
59 public ApplyUpdaterAction( final Action f, final Action a, final Action u ) {
60 this.fun = f;
61 this.args = a;
62 this.uargs = u;
63 }
64
65 /**
66 * @see org.millscript.millscript.action.Action#action(org.millscript.millscript.vm.Machine)
67 */
68 @Override
69 public void action( final Machine mc ) {
70 // Store the number of values on the stack, before generating the
71 // arguments
72 int start = mc.getCount();
73 // Generate the arguments for the function
74 args.act( mc );
75 // Store the number of values on the stack, after generating the
76 // arguments
77 int middle = mc.getCount();
78 // Generate the values to update the function with
79 uargs.act( mc );
80 // Store the number of values on the stack, after generating the update
81 // values
82 int end = mc.getCount();
83 // Generate the function we want to apply
84 fun.act( mc );
85 // Get it off the stack
86 Function f = mc.popFunction();
87 // Record the function updaters entry
88 mc.enterUpdater( f );
89 // Apply the function, telling it how many arguments and update values
90 // it has
91 f.applyUpdater( mc, middle - start, end - middle );
92 // Record the function updaters exit
93 mc.exitUpdater( f );
94 }
95 }