Say, I made this template, [[Category:{{{1}}}]][{{fullurl:Category:{{{1}}}}} {{{1}}}] ( http://radioscanningtw.jidanni.org/index.php?title=Template:C ) as I want categories clickable right where I mention them on a page.

And my site has a thousand categories that have members but no text, and should stay that way, hence the fullurl to avoid the action=edit.

Of course the categories are repeated again at the bottom of each page, but there is no __NO_CATEGORY_LIST__ to turn that off.

I suppose my template is OK. Can't think of a better way.

I suppose what I really want is something like the ISBN detection code that one can set up to match certain regexps and do certain things so one wouldn't need to use a template at all. And in the rare case when one doesn't want a match, one could use <nowiki>.

Yes, a general perl style filter that would do things on the wiki text mediawiki sees without changing what the user sees.

And all in one or two Local_Settings variables.

(Hmmm, probably just increasing the house of cards risks to the system.)