Theme parameter for the theme path

When working with diazo, I'd love to be able to have a variable like {$theme_path}
I currently have to hardcode the theme path when including specific files.
For example

 <after css:theme-children="html body">
         <script src="++theme++mytheme/js/collection-search-filter.js"></script>

It means that if I rename my theme to cooltheme and deploy to another site, I end up breaking things without also renaming all paths containing ++theme++
Following my example, I'd need to change this entry to

 <after css:theme-children="html body">
         <script src="++theme++cooltheme/js/collection-search-filter.js"></script>

If there were a theme_path variable, I could simply make it work everywhere by doing something like this:

 <after css:theme-children="html body">
         <script src="{$theme_path}/js/collection-search-filter.js"></script>

My best bet is to have a variable called theme_path but I still need to be mindful to change that if I make a copy of the theme. But at least it would be just one place to change it.

portal_url = portal_state/portal_url
theme_path = string:/++theme++mytheme

Not if you use inline CSS or javascript.
Maybe it could be saved in the registry, then it would be possible to use it in TAL templates.

But isn't there already an entry in your manifest.cfg, like:
prefix = /++theme++mytheme

I think that is the way to do it

Using prefix with relative paths or inline code is definitely another legitimate way of doing it. I've stayed away from inline after it broke my diazo rules once.