BooleanAntlrLexer lexer = new BooleanAntlrLexer( pReader );
BooleanAntlrParser parser = new BooleanAntlrParser( lexer );
parser.expr();
CommonAST ast = (CommonAST) parser.getAST();
BooleanAntlrTree tree = new BooleanAntlrTree();
return tree.expr( ast );
}