/* This file is part of SableCC ( http://sablecc.org ).
*
* See the NOTICE file distributed with this work for copyright information.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.sablecc.sablecc.walker;
import java.util.*;
import org.sablecc.sablecc.exception.*;
import org.sablecc.sablecc.lrautomaton.*;
import org.sablecc.sablecc.lrautomaton.Alternative;
import org.sablecc.sablecc.lrautomaton.Element;
import org.sablecc.sablecc.structure.*;
import org.sablecc.sablecc.syntax3.node.*;
public class ParserPriorityCollector
extends TreeWalker {
private final GlobalIndex globalIndex;
private Context currentContext;
private NormalParserProduction currentProduction;
private ParserPriorityLevel currentPriorityLevel;
public ParserPriorityCollector(
GlobalIndex globalIndex) {
this.globalIndex = globalIndex;
}
@Override
public void caseAGrammar(
AGrammar node) {
visit(node.getParser());
}
@Override
public void caseAParser(
AParser node) {
for (PParserContext parserContext : node.getParserContexts()) {
visit(parserContext);
}
}
@Override
public void caseAParserContext(
AParserContext node) {
this.currentContext = this.globalIndex.getContext(node);
for (PParserProduction parserProduction : node.getParserProductions()) {
visit(parserProduction);
}
this.currentContext = null;
}
@Override
public void caseANormalParserProduction(
ANormalParserProduction node) {
this.currentProduction = (NormalParserProduction) this.globalIndex
.getProduction(node);
for (PParserPriority pParserPriority : node.getParserPriorities()) {
visit(pParserPriority);
}
this.currentPriorityLevel = null;
this.currentProduction = null;
}
private void addToCurrentPriorityLevel(
LinkedList<TIdentifier> identifiers) {
for (TIdentifier identifier : identifiers) {
ParserAlternative alternative = (ParserAlternative) this.currentProduction
.getAlternativeOrNull(identifier.getText());
if (alternative == null) {
throw CompilerException.invalidReference(identifier);
}
Alternative grammarAlternative = alternative
.getGrammarAlternative();
int size = grammarAlternative.getElements().size();
if (size == 0) {
throw CompilerException.alternativeNotRecursive(identifier);
}
String prodName = this.currentProduction.getNameToken().getText();
// is it left recursive?
Element element = grammarAlternative.getElement(0);
if (element instanceof ProductionElement
&& ((ProductionElement) element).getProduction().getName()
.equals(prodName)) {
// check that recursion is followed by token
if (grammarAlternative.getElements().size() < 2
|| !(grammarAlternative.getElement(1) instanceof TokenElement)) {
throw CompilerException
.recursionNotFollowedByToken(identifier);
}
}
else {
// not left recursive => check that it is right recursive
element = grammarAlternative.getElement(size - 1);
if (!(element instanceof ProductionElement)
|| !((ProductionElement) element).getProduction()
.getName().equals(prodName)) {
throw CompilerException.alternativeNotRecursive(identifier);
}
}
this.currentPriorityLevel.addAlternative(grammarAlternative);
grammarAlternative.setPriorityLevel(this.currentPriorityLevel,
identifier);
}
}
@Override
public void caseALeftParserPriority(
ALeftParserPriority node) {
this.currentPriorityLevel = new ParserPriorityLevel(PriorityType.LEFT,
this.currentPriorityLevel);
addToCurrentPriorityLevel(node.getIdentifiers());
}
@Override
public void caseARightParserPriority(
ARightParserPriority node) {
this.currentPriorityLevel = new ParserPriorityLevel(PriorityType.RIGHT,
this.currentPriorityLevel);
addToCurrentPriorityLevel(node.getIdentifiers());
}
}