SearchExpressionParser parser = new SearchExpressionParser(
new SearchExpressionLexer(new StringReader(
m_searchExpression)));
parser.caseSensitive = m_caseSensitive;
parser.regex = m_regExp;
parser.searchExpression();
ast = parser.getAST();
} catch (Exception e) {
ast = null;
// nothing to do; set m_ast to null -> regular plaintext search
}