On Tue, 23 Jan 2007, Earl Miles wrote:
The $file would be a file that should live in the same directory as the .module file and tells the system which file to conditionally load when that callback is invoked. This is one of the things that creates a big advantage in this system: We could move callbacks into conditionally loaded files, allowing Drupal's minimum per-page codesize to be smaller. The 'nodeapi' hook is not run for every page load, but because hooks are anonymous right now, that code *must* be present.
Well, I am increasingly adopting a similar coding practice. A few days ago, I also split up archive.module into a small stub which registers the menu item and has a page callback, and then that page callback includes archive.inc which contains all the magic to display an archive page. This does eliminate a great deal of parsing for PHP. Although we use an opcode cache here, we observed greatly reduced memory usage if we take care of doing our own modules this way. (I don't have hard numbers unfortunately). Gabor