presto-main/src/main/java/io/prestosql/type/DateOperators.java/DateOperators/castToSlice
class DateOperators:    @ScalarOperator(CAST)
    @LiteralParameters("x")
    @SqlType("varchar(x)")
    public static Slice castToSlice(@SqlType(StandardTypes.DATE) long value)
    {
        return utf8Slice(printDate((int) value));
    }