sourcehighlight is annoyingly slow, but it does support wiki directives 
in comments. See [here](http://www.cs.unb.ca/~bremner/teaching/java_examples/snippet/ListMerge/)
for an example (tags).

> I think that is just a result of it expanding directives, and wikilinks,
> everywhere in the file, which is generally a possible problem..
> --[[Joey]]

* * * * *

I think having the option to choose source code page types from the
dropdown list is definitely a feature.  This gives users an easy way
to contribute programs (say `.pl` files) or code snippets (like, for
example, the Elisp area of the EmacsWiki).  Actually, would there any
other way to create a `.pl` file without write access to the
repository?  --[[JasonBlevins]]

> Well, you can upload them as an attachment if the wiki is configured to
> allow it. Having them in the drop down becomes a problem when there are
> so many wacky extensions in there that you can't find anything.
> --[[Joey]]

>> I should just note that the
>> [[sourcecode|todo/automatic_use_of_syntax_plugin_on_source_code_files/discussion]]
>> plugin only adds the file extensions listed in the config.  This shouldn't cause
>> massive drop-down menu pollution.  -- [[Will]]