presto-main/src/main/java/io/prestosql/operator/scalar/Re2JCastToRegexpFunction.java/Re2JCastToRegexpFunction/castCharToRe2JRegexp
class Re2JCastToRegexpFunction:    public static SqlOperator castCharToRe2JRegexp(int dfaStatesLimit, int dfaRetries)
    {
        return new Re2JCastToRegexpFunction("char(x)", dfaStatesLimit, dfaRetries, true);
    }