I am using this with 3 styles.

Do you get any php errors when switching styles? Check your logs :) White page usually means errors.

Removed this post on author's request.

orban, can you briefly explain how/why this new experimental one is better than the released product?

Well, the old one used the following "hack" for the template evals:

eval('$navbar = include("templates/1234.php");');

And that only for larger templates. Smaller ones (default setting 4500 bytes I think) were still executed the old way (even if stored in a file).

This one, however, takes a different approach.

eval('$navbar = template_1234($spacer_open, $stylevar, $GLOBALS, $welcomeheaders)');

All templates are parsed and stored in functions, and all "template function" for one page are stored in a file.

So basically all eval()s only execute a function call. This means all eval calls are nearly completely avoided, and there is just one file for every page. The files aren't too big on disk (40-100kb) but up to 2.5mb in xcache which isn't an issue though so far (I think this is because vB compiles all templates as one very long string with <if> calls being ternary conditionals).

Yeah, I noticed coding one of my plugins that using a bunch of eval()s really slows things down. I ended up rewriting the code 3 times before I came up with a way that didn't use a more than one eval() on runtime.

Thanks for the update!

What could be causing fatal undefined function errors when using the experimental code?

That the file doesn't get included, have you created a writable cache/ folder?

That's really great thinking, orban. What is stopping you from making this the default method?

Well, you can't easily "exclude" templates like in the default method so all addons that dynamically modify templates on run time will break and it's mostly untested. :)

But yeah I might release it as a second option.

Yes, it is only happening on some pages. I am thinking it is an issue with those pages, but I don't really know what to look for.

I reverted to the default method to "fix" the issue.