I agree that niladic functions are dispensable. After all, since any (normal?) verb v returns a noun, a self-updating noun could simply be written as (v ''). It is an expression, but it evaluates to a noun and is enclosed in parens, so I don't see much of a difference. And simpler is usually better.
Nevertheless, I am curious as to how one would create an actual self-updating noun. I don't know much about m-mapped files; would a J noun "point" to one? Thank you, Louis ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
