One of the features I was going to add in the next release of Daizu was a way of avoiding the need to regenerate blog articles whenever their navigation menus would change. This happens the first time a new article is published in a given month. For example, when I write the first article in December the menu to the left will need to get a new ‘December’ entry for all the pages it appears in.
I ended up deciding this was unnecessary complexity, so I undid the change, but I thought I should write down what I'd done somewhere.
Daizu blogs have navigation menus (shown to the left of this article if you are looking at it on the Daizu website). The show the years and (sufficiently recent) months in which articles were written, so that you can navigate through them by date. When an article is published in a month, and perhaps year, in which there weren't already any articles, the navigation menu needs to be updated on all the blog pages to reflect that.
I thought I'd try to be clever by having the navigation menu used by blog articles in a separate file, and have their templates include it with an SSI. Only the file containing the actual menu would have to be updated when the menu changes. The menus for the archive pages and the homepage were still included within the pages because those ones might have one of the menu items selected (in which case it doesn't appear as a link, because it's usually bad form to link to the current page).
There are a couple of problems with this. Firstly it would require anyone publishing a blog with Daizu to make sure that the blog pages were being SSI processed. Turning this on for Apache at least also makes it harder for the pages to be cached, because Apache doesn't believe the last modification date if the page might have content drawn in from other files.
On reflection I don't think this is worth it. Very few sites will have so many articles in a blog that republishing them once a month would be a problem, and really big sites would probably need their own generator classes anyway, so they could implement whatever tricks are necessary to avoid excessive page generation.
For future reference: I made the original changes to add this feature in r573 and r586 (possibly with small modifications after that). I removed it in r652, r653, and r654.