This is pretty neat! It seems to be a kind of DSL for making DSLs. The new language is defined in a grammar file and files written in the language can execute

This is pretty neat! It seems to be a kind of DSL for making DSLs. The new language is defined in a grammar file and files written in the language can execute directly by adding implementation code to the grammar definition in the form of snippets of js/python/etc associated with the kinds of syntax you define. The syntax of everything is the same: a of tree of tokens. If that sounds like a broad definition, that's because it is. Afaict the only required syntax is that the tokens form a tree; your dsl can assign arbitrary meaning to the actual structure. This might be something I could use at $work, I bet it would fit well into an automation framework. I feel like if I knew some lisp it would give me a different perspective on tree notation.