/*
* $Id$
*
* Copyright (C) 2003-2014 JNode.org
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library 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 Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; If not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
package org.jnode.shell.syntax;
import org.jnode.nanoxml.XMLElement;
/**
* A Powerset syntax allows a group of child Syntaxes to be provided in any order.
* The syntax allows a child syntax to appear more than once, subject to Argument
* multiplicity constraints. As with an Alternatives, the child syntaxes are tried
* one at a time in the same order as the they were provided to the constructor.
* The 'eager' parameter specifies whether the syntax is 'eager' (i.e. matching as
* many instances as possible) or 'lazy' (i.e. matching as few instances as possible).
*
* @author crawley@jnode.org
*/
public class PowersetSyntax extends GroupSyntax {
private final boolean eager;
public PowersetSyntax(String label, boolean eager, String description, Syntax...syntaxes) {
super(label, description, syntaxes);
this.eager = eager;
}
public PowersetSyntax(String label, Syntax...syntaxes) {
this(label, false, null, syntaxes);
}
public PowersetSyntax(Syntax...syntaxes) {
this(null, false, null, syntaxes);
}
@Override
public String toString() {
return "PowersetSyntax{" + super.toString() + "}";
}
@Override
public MuSyntax prepare(ArgumentBundle bundle) {
Syntax[] children = getChildren();
MuSyntax[] childMuSyntaxes = new MuSyntax[children.length];
for (int i = 0; i < children.length; i++) {
childMuSyntaxes[i] = children[i].prepare(bundle);
}
String label = this.label == null ? MuSyntax.genLabel() : this.label;
MuSyntax res;
if (eager) {
res = new MuAlternation(label,
new MuSequence(new MuAlternation((String) null, childMuSyntaxes),
new MuBackReference(label)),
null);
} else {
res = new MuAlternation(label, null,
new MuSequence(new MuAlternation((String) null, childMuSyntaxes),
new MuBackReference(label)));
}
res.resolveBackReferences();
return res;
}
@Override
public String format(ArgumentBundle bundle) {
StringBuilder sb = new StringBuilder();
for (Syntax childSyntax : getChildren()) {
if (sb.length() > 0) {
sb.append(" | ");
} else {
sb.append("[ ");
}
String formatted = childSyntax.format(bundle);
if (needsBracketting(formatted)) {
sb.append("( ").append(formatted).append(" )");
} else {
sb.append(formatted);
}
}
if (sb.length() > 0) {
sb.append(" ] ...");
}
return sb.toString();
}
@Override
public XMLElement toXML() {
XMLElement element = basicElement("powerSet");
if (eager) {
element.setAttribute("eager", "true");
}
return element;
}
}