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 expression.
28 *
29 * @see org.millscript.millscript.expr.ApplyExpr
30 * @see org.millscript.millscript.syntax.ParenSyntax
31 */
32 public final class ApplyAction extends Action {
33
34 /**
35 * The action generating the function to apply.
36 */
37 private Action fun;
38
39 /**
40 * The action for the arguments to the function.
41 */
42 private Action args;
43
44 /**
45 * Constructs a new function application action, with the specified actions
46 * for the function and it's arguments.
47 *
48 * @param f the action generating the function to apply
49 * @param a the action for the arguments to the function
50 */
51 public ApplyAction( final Action f, final Action a ) {
52 this.fun = f;
53 this.args = a;
54 }
55
56 /**
57 * @see org.millscript.millscript.action.Action#action(org.millscript.millscript.vm.Machine)
58 */
59 @Override
60 public void action( final Machine mc ) {
61 // Store the number of values on the stack, before generating the
62 // arguments
63 int before = mc.getCount();
64 // Generate the arguments for the function
65 args.act( mc );
66 // Store the number of values on the stack, after generating the
67 // arguments
68 int after = mc.getCount();
69 // Generate the function we want to apply
70 fun.act( mc );
71 // Get it off the stack
72 Function f = mc.popFunction();
73 // Record the function entry
74 mc.enterFunction( f );
75 // Apply the function, telling it how many arguments it has
76 f.apply( mc, after - before );
77 // Record the function's exit
78 mc.exitFunction( f );
79 }
80 }