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I believe Rust uses datafrog, Datalog as a library to implement some of its next gen solvers for traits and lifetimes. Not a lisp and maybe this still isn’t as elegant as you had in mind? Curious how this library compares for you.

https://github.com/rust-lang/datafrog





If you want to see what it looks like when you actually embed Datalog in your language, have a look at Flix: https://flix.dev/

(Select the "Usinag Datalog..." example in the code sample dropdown)

The Rust code looks completely "procedural"... it's like building a DOM document using `node.addElement(...)` instead of, say, writing HTML. People universally prefer the declarative alternative given the choice.


Haskell can do the same, and does with a lot of little embedded DSLs.

Yea I’ve wanted to try using logict to do some larger logic programming stuff. I’ve done it with list monad but found a lot of speed issues, never quite figured out why it was so slow.

Well, lists are really slow.

To be more precise: lists in your code can be really fast, if the compiler can find a way to never actually have lists in the binary it produces. If it actually has to have lists at runtime, it's generally not all that fast.


Yeah I figured that, but the combinations I was dealing with really weren’t that many.

The problem was https://xmonader.github.io/prolog/2018/12/21/solving-murder-... and trying to solve it with list monad. Someday I hope to get back to it.


The experimental "Polonius" borrow checker was first implemented with datafrog, but I believe it's been abandoned in favour of a revised (also "Polonius") datalog-less algorithm.



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