Re: Recentish C-s M-y change

[Gregory Heytings]

> Are there any examples where the prefix arg would alter the *behavior* 
> of the subcommand (make it do something different), not just set a 
> quantifier?

In isearch-mode-map, I think not.  In other places, I don't know.

Many commands in isearch-mode-map explicitly allow and use a prefix 
argument (C-q, C-r, C-s, C-w, ...).  isearch-yank-kill (C-y) and 
isearch-yank-pop (M-y) accept one, but it is unused.  I don't see what 
meaning could be attached to a numeric argument to isearch-yank-kill or 
isearch-yank-pop, so I think that using C-u to start an interactive 
selection with these two commands would make sense.