If someone wishes to invite a lot of people for a Shabbath meal, and before Shabbath he writes down the names of all the people he wishes to invite, so that when he invites them on Shabbath he won't forget some of them, or
If there is a Simha in the Synagogue, such as a Milah, and the Abi Habben (father of the baby) wants to honor several people by sending them up to the Torah, and writes a list before Shabbath of all those he wishes to call up to the Torah, the Ba'al Hasimha (the one whose celebration it is who wrote these lists) is forbidden to read from these lists on Shabbath. The Hakhamim enacted this out of fear that he might accidentally come to erase one of the names on Shabbath.
The Shammash of the Synagogue, however, is permitted to read the list. But once all the people on the list have been called, he is not permitted to read the list any more. Works that are not holy or religious in nature are not meant to be read on Shabbath. In the case of calling people up to the Torah, this is, of course, a Miswah, and is, therefore, permitted.
This is an important Halacha, and I would urge everybody to make sure that their friends know about it. Because we often see people stumble in this matter, in particular, in the case of inviting a lot of people up to the Torah on a special Shabbath.
(See Ben Ish Hai, Shanah Beh, Parashath Wayishlah, Oth Heth)
