Hy Lyla, so it’s good to contrast with Mixins, and that’s a good way to highlight the difference between the two. I would add to that a little bit, in the sense that it’s not really adding the Aside to an XBlock, more like rendering an Aside next to an XBlock — you just have to configure the platform and tell it where to render the Aside (more of an administrative task rather than a coding task, like with Mixins).
The configuration aspect is still under development, but the current state is: You install the Aside into the platform, like you do with an XBlock, via setup.py. In the platform (not the XBlock SDK yet), there is a Django admin field where you can then blacklist XBlock types (chapter, sequential, html, etc.), and the Asides will render on all remaining XBlock types.
As an example that it’s currently just a “render next to” feature, if you export a course using Asides from Studio, you will not see any Asides XML (I know Workbench shows the Aside XML at the bottom of the page, but it doesn’t show up in the main platform). Not sure if that will change in the future as the feature gets developed more.
But yes, theoretically an Aside could be rendered next to any XBlock, despite the fact that the Aside is not declared in the XBlock’s source code.
Hope that helps…
Cole