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Lambda Calculus - Fundamentals of Lambda Calculus & Functional Programming in JavaScript

Fullstack Academy

58K subscribers • 1 video on Hallway

YouTube
  • Recommended by 9 people: 5 on Hacker News, 1 on Lobsters and 3 in engineering communities.
  • A classic. People kept recommending it from 2017 to 2024.
  • Presented by Gabriel Lebec
  • Linked in the descriptionglebec/lambda-talk

Intermediate. Assumes working knowledge.

227K views9 years ago9 recommendations

Computer scienceProgramming languagesComputation and complexityFunctional programmingJavaScript

Gabriel Lebec introduces lambda calculus syntax, combinators, and Church encodings, demonstrating how functional programming concepts map to JavaScript.

Fullstack Academy was recently ranked the #1 coding bootcamp in the U.S. Learn more at fullstackacademy.com The Lambda Calculus is a symbol manipulation system which suffices to calculate anything calculable. This branch of pure mathematics forms the backbone of functional programming languages, and here it is presented through the concrete and familiar lens of JavaScript. In this Lambda Calculus video you will learn: - Lambda Calculus Syntax - History of the foundations of mathematical logic - The essence of functional programming 🔗 Part II: youtu.be/pAnLQ9jwN-E 🔗 Slides: bit.ly/2xpcPKn 🔗 Repo: github.com/glebec/lambda-talk

Why it's here

9 people recommend this

What people say. Highly recommended as one of the most approachable and visually pleasing introductions to lambda calculus and combinators.

u/anotherexstnslcrisisin r/haskell • Recommends

As a programmer who’s explicitly only dealt with Python and is now attempting to learn Haskell, this video is one of the most beautifully presented videos explaining the use of Lamba Calculus in settings where languages such as JavaScript would be implemented.
75View on Reddit

u/fagnerbrackin r/Frontend • Recommends

Fundamentals of Lambda Calculus & Functional Programming in JavaScript
24View on Reddit

triyambakamon Hacker News • Recommends

On “All you need is λ, part one: booleans”

Just last night I found this excellent introduction to the Lambda Calculus by Gabriel Lebec 1. It's one of the best I've come across and covers briefly history, building up combinators (using Smullyan's names) leading up to implementing Church encodings and gives Javascript equivalents (or approximations when not possible). The slides themselves are also very aesthetically pleasing, Gabriel has a good sense of colour and design 1 link to this video
View on Hacker News

autophagianon Hacker News • Recommends

On “Logic”

For anyone interested in the topic (combinatory logic as told through the medium of birds) I adore Gabriel Lebec's talk "A Flock Of Functions: Combinators, Lambda Calculus & Church Encodings in JavaScript" link to this video
View on Hacker News

Zhylon Hacker News • Recommends

On “Ask HN: What resources do you recommend for learning Haskell?”

I found these two videos on combinators and lambda calculus recently. They're only tangentially related to Haskell, but they are the most approachable videos on the topic I have ever seen. link to this video link
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ayushgpon Hacker News • Recommends

On “Lisp is not based on the Lambda Calculus”

I suggest you to watch this video if you want to understand how 3 basic functions can be used to create whole language link to this video
View on Hacker News

zellynon Hacker News • Recommends

On “A little closer to finding what became Moses Schönfinkel (2021)”

I would start with lambda calculus. If you pick the right intro video, they'll stray into combinators: link to this video is very good.
View on Hacker News

agent281on Lobsters • Recommends

Fundamentals of Lambda Calculus & Functional Programming in JavaScript
3View on Lobsters

u/sabas123in r/compsci • Recommends

Lambda Calculus - Fundamentals of Lambda Calculus & Functional Programming in JavaScript
1View on Reddit

u/gabedamienin r/functionalprogramming • Mentions

On “is there a heuristic for understanding what a y Combinator is As a beginner in FP”

I can take a crack at it, as someone who made two videos on lambda calculus / combinatorial logic. ## Combinators Let's start with what a combinator is. In short, it's a function that _only_ uses its parameters, and nothing else – i.e. no "free" variables. Some examples: λ x . x -- I / identity λ a b . a -- K / first / const λ a b . b -- KI / second λ f a b . f b a -- C / flip λ f g a . f (g a) -- B / composition And some counter-examples: λ f . f x -- where does x come from? λ f a . f (g a) -- where does g come from? λ n . 1 + n -- where do 1 and + come from? λ x . (x, x) -- where doe…
23View on Reddit

u/StevenJacin r/compsci • Mentions

Lambda Calculus: What are these notation and how to read them? From [video So ::= means "defined as" What does | mean? Why is there expression expression written twice on the second line? Concrete examples would be appreciated. https://preview.redd.it/ywk7gr8g2jwc1.png?width=1247&format=png&auto=webp&s=51983d7748e011ed53322cda56418685016dbc14
18View on Reddit

u/kensuke155in r/functionalprogramming • Mentions

On “Looking for a conceptual introduction to FP and programming paradigms in general”

This might be too abstract and doesn't exactly address FP applications, but it's my favorite FP related talk by far: link to this video
6View on Reddit

u/thinline20in r/functionalprogramming • Mentions

On “Seeking advice on choosing a functional programming language”

I suggest you start with the ones you already know. You said you are using Python now and I think Python is a great choice to start with since you already know how to use it. link to this video link to this video These videos are about Lambda Calculus and combinators. Lambda calculus is a great starting point when trying out fp style. It is easy to understand and can be applicable to any languages.
4View on Reddit

u/kensuke155in r/functionalprogramming • Mentions

On “Looking for an FP video.”

This isn’t it either, but it’s very similar to what you’re describing and is my favorite programming video ever: link to this video The second part of this presentation also goes over numbers defined by the successor function. You can see this in action in the prelude of Sheepda: https://github.com/jtolio/sheepda/blob/master/interview-probs/prelude.shp#L13
3View on Reddit

u/ScientificBeastModein r/functionalprogramming • Mentions

On “Finding what language to learn (OOP? Haskell? Erlang? Idris?)”

Hello, I just want to offer this to you as a resource: link to this video Its an hour-long video, but well worth your time, given the questions you have asked here. It’s a pretty solid overview of some of the math theory behind functional programming. I’ve been into FP for a while now, and I still refer back to this video (or at least the slide-deck provided in the video description). The focus of the presentation is about lambda calculus and various function combinators, and how they build upon each other to create a robust computational system. It really helps provide some context for more practical, higher-level FP concepts. I put this knowledge into practice quite often, even if I don’t always u…
2View on Reddit

u/adlxin r/compsci • Mentions

On “Can someone explain to me lambda calculus?”

Just saw the question, I haven't read any comment. Hope no one did already answer that. Sorry if anyone did. This is the one video that i think you need to watch: link to this video
1View on Reddit