/*
* RegexSimpleHelper.java
*
* Copyright (c) 2006-2007 David Holroyd
*
* 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 uk.co.badgersinfoil.metaas.impl.parser;
import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import org.antlr.runtime.ANTLRReaderStream;
import org.antlr.runtime.CharStream;
import org.antlr.runtime.RecognitionException;
import org.asdt.core.internal.antlr.AS3Lexer;
import uk.co.badgersinfoil.metaas.impl.AS3FragmentParser;
import uk.co.badgersinfoil.metaas.impl.antlr.LinkedListToken;
import uk.co.badgersinfoil.metaas.impl.antlr.LinkedListTokenSource;
import uk.co.badgersinfoil.metaas.impl.antlr.LinkedListTokenStream;
import uk.co.badgersinfoil.metaas.impl.antlr.LinkedListTree;
import uk.co.badgersinfoil.metaas.impl.antlr.LinkedListTreeAdaptor;
import uk.co.badgersinfoil.metaas.impl.parser.regexsimple.RegexSimpleParser;
import uk.co.badgersinfoil.metaas.impl.parser.regexsimple.RegexSimpleLexer;
public class RegexSimpleHelper {
private static final LinkedListTreeAdaptor TREE_ADAPTOR = new LinkedListTreeAdaptor();
/**
* Creates a properly-configured parser object for the E4X grammar.
*/
public static RegexSimpleParser parserOn(Reader in) throws IOException {
ANTLRReaderStream cs = new ANTLRReaderStream(in);
RegexSimpleLexer lexer = new RegexSimpleLexer(cs);
LinkedListTokenSource source = new LinkedListTokenSource(lexer);
LinkedListTokenStream stream = new LinkedListTokenStream(source);
RegexSimpleParser parser = new RegexSimpleParser(stream);
parser.setTreeAdaptor(TREE_ADAPTOR);
parser.setInput(lexer, cs);
return parser;
}
public static LinkedListTree parseRegexpLiteral(LinkedListToken startMarker, AS3Lexer lexer, CharStream cs, LinkedListTokenStream stream) throws RecognitionException {
String tail = cs.substring(cs.index(), cs.size()-1);
int initialTailLength = tail.length();
RegexSimpleParser parser;
try {
parser = regexpParserOn(new StringReader(tail), stream);
} catch (IOException e) {
// TODO: better exception type?
throw new RuntimeException(e);
}
LinkedListTree ast = AS3FragmentParser.tree(parser.regexpLiteral());
tail = parser.getInputTail();
// skip over the regexp in the original, underlying CharStream
cs.seek(cs.index() + (initialTailLength - tail.length()));
LinkedListTokenSource source = (LinkedListTokenSource)stream.getTokenSource();
stream.setTokenSource(source); // cause any remembered RegexpSimple state to be dropped
stream.scrub(1); // erase the subsequent token that the RegexpSimple parser got from this stream
source.setDelegate(lexer);
return ast;
}
private static RegexSimpleParser regexpParserOn(Reader in, LinkedListTokenStream stream) throws IOException {
ANTLRReaderStream cs = new ANTLRReaderStream(in);
RegexSimpleLexer lexer = new RegexSimpleLexer(cs);
LinkedListTokenSource source = (LinkedListTokenSource)stream.getTokenSource();
source.setDelegate(lexer);
// The AS3 grammar will see the initial '/' as an DIV (divide)
// token, and lookahead in the AS3Parser will have already
// grabbed references to that token in order to make it the
// startToken for various AST subtrees, so we can't just delete
// it. We therefore find the DIC token and change its type to
// match the regexp vocabulary, and then rewind the token stream
// so that this will be the first token that the
// SinpleRegexpParser will see.
LinkedListToken startMarker = (LinkedListToken)stream.LT(-1);
startMarker.setType(RegexSimpleParser.REGEXP_DELIMITER);
stream.seek(stream.index()-1);
RegexSimpleParser parser = new RegexSimpleParser(stream);
parser.setTreeAdaptor(new LinkedListTreeAdaptor());
parser.setInput(lexer, cs);
return parser;
}
}