Gödel, Escher, Elisp: The Beauty of Macros

> 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.

	▲	wk_end an hour ago \| parent \| next [-]
		Indeed: https://hackage-content.haskell.org/package/base-4.22.0.0/do...
	▲	brabel an hour ago \| parent \| prev [-]
		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!

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thisisauserid 44 minutes ago | parent | prev | next [-]

I always thought it odd that Penrose gets dropped from the Escher conversations.

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kimi 2 hours ago | parent | prev | next [-]

Remember the golden rule of Lisp macros: don't write a macro.

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KeenanKeenan 2 hours ago | parent | prev [-]

If macros can implement arbitrary language features then how come elisp has never built a type system?

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BeetleB an hour ago | parent | next [-]

I would expect you can.

lexilambda created Typed Racket on top of Racket. https://github.com/racket/typed-racket

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wk_end an hour ago | parent | prev [-]

Well, not elisp, but

https://coalton-lang.github.io

or maybe

https://shen-language.github.io

	▲	KeenanKeenan an hour ago \| parent [-]
		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.