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;
}