Yesterday, I read a shortened version of this paper at http://www.aaai.org/ojs/index.php/aimagazine/article/viewFil... because I couldn't find the full one. Thanks for posting this!
Would highly recommend the tutorial as it is really well done.
So not very up to date, but I suppose mitigations haven't changed significantly upstream since then.
That tells me way more than snippets ever will.
The why in this case is "a little toy language ... to learn .. how dynamically-typed interpreted languages worked"
The linked page on github https://thrax.elijahpotter.dev/ has some snippets that you can click on. The first one called tour.th has a very brief overview of the language.