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/*
* Do.java
*
* Copyright (C) 2003-2006 Peter Graves
* $Id$
*
* 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 final class Do {
// ### do
private static final SpecialOperator DO = new sf_do();
private static final class sf_do extends SpecialOperator {
sf_do() {
super(Symbol.DO, "varlist endlist &body body");
}
@Override
public LispObject execute(LispObject args, Environment env)
{
return _do(args, env, false);
}
};
// ### do*
private static final SpecialOperator DO_STAR = new sf_do_star();
private static final class sf_do_star extends SpecialOperator {
sf_do_star() {
super(Symbol.DO_STAR, "varlist endlist &body body");
}
@Override
public LispObject execute(LispObject args, Environment env)
{
return _do(args, env, true);
}
};
static final LispObject _do(LispObject args, Environment env,
boolean sequential)
{
LispObject varlist = args.car();
LispObject second = args.cadr();
LispObject end_test_form = second.car();
LispObject result_forms = second.cdr();
LispObject body = args.cddr();
// Process variable specifications.
final int numvars = varlist.length();
Symbol[] vars = new Symbol[numvars];
LispObject[] initforms = new LispObject[numvars];
LispObject[] stepforms = new LispObject[numvars];
for (int i = 0; i < numvars; i++) {
final LispObject varspec = varlist.car();
if (varspec instanceof Cons) {
vars[i] = checkSymbol(varspec.car());
initforms[i] = varspec.cadr();
// Is there a step form?
if (varspec.cddr() != NIL)
stepforms[i] = varspec.caddr();
} else {
// Not a cons, must be a symbol.
vars[i] = checkSymbol(varspec);
initforms[i] = NIL;
}
varlist = varlist.cdr();
}
final LispThread thread = LispThread.currentThread();
final SpecialBindingsMark mark = thread.markSpecialBindings();
// Process declarations.
final LispObject bodyAndDecls = parseBody(body, false);
LispObject specials = parseSpecials(bodyAndDecls.NTH(1));
body = bodyAndDecls.car();
Environment ext = new Environment(env);
for (int i = 0; i < numvars; i++) {
Symbol var = vars[i];
LispObject value = eval(initforms[i], (sequential ? ext : env), thread);
ext = new Environment(ext);
if (specials != NIL && memq(var, specials))
thread.bindSpecial(var, value);
else if (var.isSpecialVariable())
thread.bindSpecial(var, value);
else
ext.bind(var, value);
}
LispObject list = specials;
while (list != NIL) {
ext.declareSpecial(checkSymbol(list.car()));
list = list.cdr();
}
// Look for tags.
LispObject localTags = preprocessTagBody(body, ext);
LispObject blockId = new LispObject();
try {
// Implicit block.
ext.addBlock(NIL, blockId);
while (true) {
// Execute body.
// Test for termination.
if (eval(end_test_form, ext, thread) != NIL)
break;
processTagBody(body, localTags, ext);
// Update variables.
if (sequential) {
for (int i = 0; i < numvars; i++) {
LispObject step = stepforms[i];
if (step != null) {
Symbol symbol = vars[i];
LispObject value = eval(step, ext, thread);
if (symbol.isSpecialVariable()
|| ext.isDeclaredSpecial(symbol))
thread.rebindSpecial(symbol, value);
else
ext.rebind(symbol, value);
}
}
} else {
// Evaluate step forms.
LispObject results[] = new LispObject[numvars];
for (int i = 0; i < numvars; i++) {
LispObject step = stepforms[i];
if (step != null) {
LispObject result = eval(step, ext, thread);
results[i] = result;
}
}
// Update variables.
for (int i = 0; i < numvars; i++) {
if (results[i] != null) {
Symbol symbol = vars[i];
LispObject value = results[i];
if (symbol.isSpecialVariable()
|| ext.isDeclaredSpecial(symbol))
thread.rebindSpecial(symbol, value);
else
ext.rebind(symbol, value);
}
}
}
if (interrupted)
handleInterrupt();
}
LispObject result = progn(result_forms, ext, thread);
return result;
} catch (Return ret) {
if (ret.getBlock() == blockId) {
return ret.getResult();
}
throw ret;
}
finally {
thread.resetSpecialBindings(mark);
ext.inactive = true;
}
}
}
