[NTG-context] automatic page sizes?

Dear everyone, I do know that this question has been answered here before, but I've not been able to find it in the archive (and my personal copy got lost when the harddrive of my previous laptop went berserk). How do I make ConTeXt emit a pdf file where each page is just as long as necessary for the text on it, up to say 1 meter? Page breaks would usually, but not always, be initiated by some macro or other; footers are not used (yet?). Regards, Christopher Creutzig