Gödel, Escher, Elisp: The Beauty of Macros
chiply.dev26 points by JNRowe 10 days ago
26 points by JNRowe 10 days ago
> To anticipate a common question: why couldn't my-unless be a function? Function arguments are evaluated eagerly, before the function ever sees them.
Interesting, so if you’re using a lazy language then you don’t need a macro here and could write my-unless as a function.
Yes, the D language has that as a feature in function arguments!
https://dlang.org/articles/lazy-evaluation.html
It makes it hard to know when things run. In Lisp you also have that problem everywhere, of course.
As the post shows this allows you to do stuff that looks like extending the syntax of the language.
I can’t decide if I love it or hate it!
I always thought it odd that Penrose gets dropped from the Escher conversations.
Remember the golden rule of Lisp macros: don't write a macro.
If macros can implement arbitrary language features then how come elisp has never built a type system?
I would expect you can.
lexilambda created Typed Racket on top of Racket. https://github.com/racket/typed-racket
Typed racket too, might I add. I just imagine static typing around stable core APIs would help users understand how eglot and vertico compare to prior art. The way I learned how the completion stack works was to ask claude to show me what the elisp entrypoints would look like if implemented in typescript. It's not because I'm unfamiliar with lisp, I'm not, it's just easier to reason with the world in terms of data structures and their contracts.