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Common Lisp implementation running on the JVM
/*
* LispStackFrame.java
*
* Copyright (C) 2009 Mark Evenson
* $Id: LispStackFrame.java 13440 2011-08-05 21:25:10Z ehuelsmann $
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* As a special exception, the copyright holders of this library give you
* permission to link this library with independent modules to produce an
* executable, regardless of the license terms of these independent
* modules, and to copy and distribute the resulting executable under
* terms of your choice, provided that you also meet, for each linked
* independent module, the terms and conditions of the license of that
* module. An independent module is a module which is not derived from
* or based on this library. If you modify this library, you may extend
* this exception to your version of the library, but you are not
* obligated to do so. If you do not wish to do so, delete this
* exception statement from your version.
*/
package org.armedbear.lisp;
import static org.armedbear.lisp.Lisp.*;
public class LispStackFrame
extends StackFrame
{
public final LispObject operator;
private final LispObject first;
private final LispObject second;
private final LispObject third;
private final LispObject[] args;
private final class UnavailableArgument extends LispObject
{
public UnavailableArgument () { }
@Override
public String printObject() {
return unreadableString("unavailable arg", false);
}
}
private final LispObject UNAVAILABLE_ARG = new UnavailableArgument();
public LispStackFrame(LispObject operator)
{
this.operator = operator;
first = null;
second = null;
third = null;
args = null;
}
public LispStackFrame(LispObject operator, LispObject arg)
{
this.operator = operator;
first = arg;
second = null;
third = null;
args = null;
}
public LispStackFrame(LispObject operator, LispObject first,
LispObject second)
{
this.operator = operator;
this.first = first;
this.second = second;
third = null;
args = null;
}
public LispStackFrame(LispObject operator, LispObject first,
LispObject second, LispObject third)
{
this.operator = operator;
this.first = first;
this.second = second;
this.third = third;
args = null;
}
public LispStackFrame(LispObject operator, LispObject... args)
{
this.operator = operator;
first = null;
second = null;
third = null;
this.args = args;
}
@Override
public LispObject typeOf() {
return Symbol.LISP_STACK_FRAME;
}
@Override
public LispObject classOf() {
return BuiltInClass.LISP_STACK_FRAME;
}
@Override
public String printObject()
{
String result = "";
final String LISP_STACK_FRAME = "LISP-STACK-FRAME";
try {
result = Symbol.PRIN1_TO_STRING.execute(this.toLispList()).printObject();
} catch (Throwable t) { // error while printing stack
Debug.trace("Serious printing error: ");
Debug.trace(t);
result = unreadableString(LISP_STACK_FRAME);
}
return result;
}
@Override
public LispObject typep(LispObject typeSpecifier)
{
if (typeSpecifier == Symbol.LISP_STACK_FRAME)
return T;
if (typeSpecifier == BuiltInClass.LISP_STACK_FRAME)
return T;
return super.typep(typeSpecifier);
}
public LispObject toLispList()
{
LispObject result = argsToLispList();
if (operator instanceof Operator) {
LispObject lambdaName = ((Operator)operator).getLambdaName();
if (lambdaName != null && lambdaName != Lisp.NIL)
return result.push(lambdaName);
}
return result.push(operator);
}
private LispObject argsToLispList()
{
LispObject result = Lisp.NIL;
if (args != null) {
for (int i = 0; i < args.length; i++)
// `args' come here from LispThread.execute. I don't know
// how it comes that some callers pass NULL ptrs around but
// we better do not create conses with their CAR being NULL;
// it'll horribly break printing such a cons; and probably
// other bad things may happen, too. --TCR, 2009-09-17.
if (args[i] == null)
result = result.push(UNAVAILABLE_ARG);
else
result = result.push(args[i]);
} else {
do {
if (first != null)
result = result.push(first);
else
break;
if (second != null)
result = result.push(second);
else
break;
if (third != null)
result = result.push(third);
else
break;
} while (false);
}
return result.nreverse();
}
public SimpleString toLispString()
{
String result;
try {
result = this.toLispList().printObject();
} catch (Throwable t) { // error while printing stack
Debug.trace("Serious printing error: ");
Debug.trace(t);
result = unreadableString("LISP-STACK-FRAME");
}
return new SimpleString(result);
}
public LispObject getOperator() {
return operator;
}
@Override
public LispObject getParts()
{
LispObject result = NIL;
result = result.push(new Cons("OPERATOR", getOperator()));
LispObject args = argsToLispList();
if (args != NIL) {
result = result.push(new Cons("ARGS", args));
}
return result.nreverse();
}
}