Recently in a huge flurry of Wordpress related googling I came across a possible solution to my problem of that time which used a method I hadn't come across before: Part of the process was including in the functions.php file the code which would have otherwise been placed in the template files of the site. That code was then "injected" into the theme files with one simple line of code. Something like:
<?php insert_custom_code(); ?>
I loved how clean this kept the template files, by allowing me to write the code related to some trickery and tucking it away in functions. Now I've also learned about creating site specific plugins so I can wrap that sort of stuff up in even tidier packages. Unfortunately that specific solution didn't work for my problem at that time, and I've lost that information.
I think this is a straight forward and standard part of Wordpress work - especially related to plugin and theme development, but I'm not sure what it's called or how to find it. So my question is: Does anyone know what this is called? Or where it might live in the wordpress codex or any other documentation that might help? I really appreciate it.