>>> -   (concat
>>> -    (when delete "Delete ")
>>> -    (package-menu--list-to-prompt delete)
>>> -    (when (and delete install)
>>> -      (if upgrade "; " "; and "))
>>> -    (when install "Install ")
>>> -    (package-menu--list-to-prompt install)
>>> -    (when (and upgrade (or install delete)) "; and ")
>>> -    (when upgrade "Upgrade ")
>>> -    (package-menu--list-to-prompt upgrade)
>>> -    "? ")))
>>> +   (format "Number of packages to delete: %s / install: %s / upgrade: %s, proceed? "
>>> +	   (package-menu--list-to-prompt delete)
>>> +	   (package-menu--list-to-prompt install)
>>> +	   (package-menu--list-to-prompt upgrade))))
>> 
>> This loses the feature of saying just what's needed, instead of
>> showing zero.  Can we do better?
> 
> If you ask, there probably is a way... I'll try to find something better.

Ok, I found something for this part that I also adapted to 2 other parts that I had overly simplified. I also made a few modifications here and there compared to my original file.

Jean-Christophe