presto-main/src/main/java/io/prestosql/operator/scalar/JoniRegexpCasts.java/JoniRegexpCasts/castCharToJoniRegexp
class JoniRegexpCasts:    @ScalarOperator(OperatorType.CAST)
    @LiteralParameters("x")
    @SqlType(JoniRegexpType.NAME)
    public static Regex castCharToJoniRegexp(@LiteralParameter("x") Long charLength, @SqlType("char(x)") Slice pattern)
    {
        return joniRegexp(padSpaces(pattern, charLength.intValue()));
    }