alt Hacker NewsMakes me think of Boo language; Boo was so good at metaprogramming and multi-phasr programming! A very fine .NET language that was so far ahead of the curve, with having the tools of that language be usable at runtime.
Alas many of the docs are offline now. But it had great quasiquotes, which let you write code that gets turned into AST that you can then process. Good macros. A programmable compiler pipeline. So much. Alas, obscured now. https://boo-language.github.io/
Boo and Nemerle both were really showing what was possible in .NET back in the early days. I still miss the metaprogramming they had, not to mention their pattern matching (which C# has closed the gap on, but is still way, way short.)