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Comment by lucasoshiro | Hacker News Reader

If you like this subject, I wrote a quicksort in lambda calculus in Python: https://news.ycombinator.com/item?id=38848905

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Nice. Last November I wrote a implementation of a type checker for the STLC in typescript using mogensen-scott encoding. The idea is that data is represented by its eliminator, so you kind of get pattern matching in javascript.

I had been playing around with the idea and thought I'd try a larger example to see how painful it was to work with. I don't think I would build anything bigger with that technique, though.

https://gist.github.com/dunhamsteve/1be0cbb346d75ee1be8f67d1...

This looks great! Bruijn actually has something similar in its standard library [1] but without your `partition`, so it's much less efficient.

[1]: https://bruijn.marvinborner.de/std/List_Church.bruijn.html#s...

Unrelated comment: I love the Tex in your code comments, and I wish that auto-previewing it was a feature of IDEs (especially emacs)

It's not quite a preview, but back in the 90's there was something called sym-lock.el that would render TeX escape sequences as the corresponding symbol. I have no idea if it still works, but Google points me here:

  https://github.com/sid137/emacs/blob/master/sym-lock.el

(I used it with xemacs at the time, because it had more flexible font handling.)

Emacs can do that quite easily[1]. But this code is not merged into the trunk yet, it should be some time this year.

[1]: https://share.karthinks.com/prog-preview-3.mp4

That's exactly what I had in mind, is it just a modified org-latex-preview that works anywhere?

Thanks!

PS: Nice work :-)

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