[wp-hackers] Issue with passing results from get_the_category through do_action

[Claude Needham]

I have written a small bit of code that would (hopefully) allow me to
select the best or most appropriate category for a post. For a post
with just one category this is easy. For a post with multiple
categories this requires a smart system of some sort.

Never mind that. My problem is in trying to figure out how to properly
pass the $categories object through the do_action system.

The code is something like the following:

in single.php