01: /*
02: * Jatha - a Common LISP-compatible LISP library in Java.
03: * Copyright (C) 1997-2005 Micheal Scott Hewett
04: *
05: * This library is free software; you can redistribute it and/or
06: * modify it under the terms of the GNU Lesser General Public
07: * License as published by the Free Software Foundation; either
08: * version 2.1 of the License, or (at your option) any later version.
09: *
10: * This library is distributed in the hope that it will be useful,
11: * but WITHOUT ANY WARRANTY; without even the implied warranty of
12: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13: * Lesser General Public License for more details.
14: *
15: * You should have received a copy of the GNU Lesser General Public
16: * License along with this library; if not, write to the Free Software
17: * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18: *
19: *
20: * For further information, please contact Micheal Hewett at
21: * hewett@cs.stanford.edu
22: *
23: */
24:
25: package org.jatha.machine;
26:
27: import org.jatha.Jatha;
28: import org.jatha.dynatype.*;
29:
30: // @date Sat Feb 1 22:18:53 1997
31: /**
32: * opAP applies a non-recursive function in an evaluation environment.
33: * ((f.e') v.s) e (AP.c) d --> NIL (v.e') f (s e c.d)
34: * Replaces the C register with the CAR of the topmost value on the S register.
35: * Pushes the C, E and S registers onto the D register, in that order.
36: * Replaces the E register with a cons of the second value on the S
37: * register and the cdr of the first value.
38: * Places NIL in the S register.
39: * @see SECDMachine
40: * @author Micheal S. Hewett hewett@cs.stanford.edu
41: */
42: class opAP extends SECDop {
43: /**
44: * It calls <tt>SECDop()</tt> with the machine argument
45: * and the label of this instruction.
46: * @see SECDMachine
47: */
48: public opAP(Jatha lisp) {
49: super (lisp, "AP");
50: }
51:
52: public void Execute(SECDMachine machine) {
53:
54: LispValue fe = machine.S.pop(); /* (f . e) */
55: LispValue v = machine.S.pop();
56:
57: /*
58: printf("\nAP: fe = "); print(fe);
59: printf("\nAP: v = "); print(v);
60: */
61:
62: LispValue code = fe.car();
63: if (code instanceof LispFunction)
64: code = ((LispFunction) code).getCode();
65:
66: machine.C.pop(); // Get rid of 'AP' opcode.
67:
68: machine.D.assign(f_lisp.makeCons(machine.S.value(), f_lisp
69: .makeCons(machine.E.value(), f_lisp.makeCons(machine.C
70: .value(), machine.D.value()))));
71: machine.C.assign(code);
72: machine.E.assign(f_lisp.makeCons(v, fe.cdr()));
73: machine.S.assign(f_lisp.NIL);
74: }
75: }
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