RE: simple requirement, so simple don't know how to search

[Drew Adams]

        Thanks for the info, but registers limit the marked entries
        and I will not be able to cycle through them. So that is 
        out of the question.
        After looking around I found thing-cmds.el . The description
        looks good but I need to try it out.
        I'm looking for something like:
        press F2 -> put the current position where cursor is in a
                  list with limit of 20 entries.
        press F3 -> go forward in the list.
        press F4 -> go backward in the list.

I wrote thing-cmds.el. Dunno if it will help you here - it's not clear to me
what you really want to do. I thought previously that what you wanted was
essentially bookmarks.
 
Now you say you just want to move through a list, that is, move forward a sexp
(list element) at a time. For that you can use `C-M-f', `C-M-b', and so on. What
you mean by your description of F2 is also unclear to me.

People's replies to you have been all over the map, which is an indication that
maybe your requirement isn't well specified. ;-) Most replies take the need to
be to bounce around among predefined positions. Hence people have suggested
marks (and global marks), registers, and bookmarks, all of which let you do
that.