A Flock of Functions: Lambda Calculus and Combinatory Logic in JavaScript | Gabriel Lebec @ DevTalks

The Lambda Calculus is a tiny symbol manipulation system which suffices to compute anything Turing-computable. Thanks to this expressive power, LC is woven into the DNA of functional programming languages. In this talk, the surprises and delights of LC and related formalisms are demonstrated through the familiar lens of JavaScript.
Gabriel's slides:
speakerdeck.com/glebec/lambda...
Gist of the Q&A part:
gist.github.com/glebec/7d9d14...
See part II of Gabriel's talk at:
github.com/glebec/lambda-talk
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October 2019 | Smartly.io DevTalks
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[@DumblyDorr]

Great talk! I'd probably put Cantor and Gentzen on that historical slide, too (and note that Russell's paradox was noticed by Frege).

[@DevineLuLinvega]

Interobang spotted!! Nice talk, it made a lot of things clearer, thank you.

[@neilbedwell7763]

There is something incredibly daoist about boolean logic and equality expressed as combinators

[@marcfoster715]

Which is probably why Raymond Smullyan loved combinatory logic.

[@mskiptr]

Wow! That is one awesome talk!

[@qu4ku]

great talk, thanks to the author.

[@helloimwill]

Once thought an idiot bird, later was found to be fond of all other birds and itself. 🥰

[@Ancipital_]

Can someone please explain to me λf.ff. In particular the ff after the period. Can this be reduced and if so, how? I don't understand how to understand this 😸
(λf.ff)λa.a = (λa.a)λa.a .. i get it but i don't get it.

[@Coolbassist]

λf.ff takes a function f, and applies f to f. You're correct in that (λf.ff)λa.a = (λa.a)λa.a. λa.a is the identity function, which we can call I. So (λf.ff)I is equal to II, which is the identity function applied to the identity function. Which returns just the identity function, I.

[@zekodun]

curious how this works for SKI commentators?

[@caosed4991]

Google changes people. Hmm or maybe its just age.😶

in what way? i only watched the older video

[@caosed4991]

@ i honestly don't remember why I made that comment, but i think it was because in this video it looks like they talk in a more lower level language? If that makes sense. In this video they are talking in javascript, unlike the other video, where they were talking in math more. And I don't think that's a great thing. Just a personal opinion.

[@glebec]

LOL, it could just be that I was jet lagged from flying from NYC to Helsinki the night before. 😅