Earlier quoted context omitted.
The language is the least interesting part of this. What is interesting is if it was truly built with a simple loop and without manual involvement to produce a working compiler (albeit with fairly cursed code... 5.5kloc for a parser for a grammar that appears this simple is not great) Sadly, the linked page glosses over the specifics of the setup and instead focused on the less interesting parts..
It produced...something, alright. Something that can be replaced by a very small shell script.
And that is entirely irrelevant, as the purpose was to produce a compiler.
As an experiment this is amazing in terms of telling us a lot about how capable these tools are. Most developers would not be capable of producing a working compiler and the associated tooling in this kind of timeframe.