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Ruby Conf 12 - Y Not- Adventures in Functional Programming by Jim Weirich

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42K subscribers • 74 videos on Hallway • Conference channel

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  • Recommended by 18 people: 17 on Hacker News and 1 in engineering communities.
  • A classic. People kept recommending it from 2012 to 2026.
  • Presented by Jim Weirich

Intermediate. Assumes working knowledge.

65K views13 years ago18 recommendations

Programming languagesComputer scienceFunctional programmingRubyComputation and complexity

Jim Weirich derives the Y combinator step by step using Ruby lambdas to explain functional programming and lambda calculus from first principles.

One of the deepest mysteries in the functional programming world is the Y-Combinator. Many have heard of it, but few have mastered its mysteries. Although fairly useless in real world software, understanding how the Y-Combinator works and why it is important gives the student an important insight into the nature of functional programming. Join with us on this journey of understanding. Be prepared to curry your functions and bind your lambdas as we delve into the whys and wherefores of this paragon of functional programming. Although you will probably never have a need for the combinator, the effort put forth to understand it will improve your functional programming chops. This talk is not for the faint of heart, but the successful student will be richly rewarded. Also, you will understand why "Y-Combinator" is the perfect name for Paul Graham's start-up funding company. At the end of his talk Jim references Tom Stuart's talk "Programming with Nothing" which can be found here: youtube.com/watch?v=VUhlNx_-wYk Help us caption & translate this video! amara.org/v/FGer/

Why it's here

18 people recommend this

What people say. Recommended as a legendary, highly entertaining, and approachable step-by-step live-coded derivation of the Y combinator.

Moments people linked to

mekishizufuon Hacker News • Recommends

On “What is a y-combinator? (2008)”

If you are curious about the topic, I strongly recommend watching these videos: Y Not- Adventures in Functional Programming by Jim Weirich link to this video Programming with Nothing by Tom Stuart link

VeejayRampayon Hacker News • Recommends

On “So very sad to hear about the passing of Ruby legend Jim Weirich”

link to this video This talk is a must-see, really shows off Jim Weirich's craft and overall ability to be a great pedagogue.

careersuicideon Hacker News • Recommends

On “Writing code doesn't mix well with oration”

Jim Weirich's "Y Not - Adventures in Functional Programming"1 is perhaps the most entertaining and interesting technical talk I've ever seen. It would absolutely not be as cool or as fun without the live coding. Additionally, the incremental process by which he arrives at the conclusion makes the topic much more approachable. 1. link to this video

JamilDon Hacker News • Recommends

On “What is a Y Combinator?”

For those (like me) that prefer learning through talks and demonstrations, Jim Wierich gave an incredible talk on the Y Combinator at RubyConf 2012. Video: link to this video Code: link

webdevatlurkon Hacker News • Recommends

On “Ask HN: What is your favourite tech talk?”

…e an account to post in this thread. I'm rather early in my career doing mostly Ruby, Python and JavaScript things. As you might expect, I consume mainly Ruby, Python and JavaScript related talks. The first two talks that really blew my mind are: - K Lars Lohn's PyCon Keynote from 2016: link - Jim Weirich's (RIP) "Y Not" talk from RubyConf 2012: link to this video There are many other presenters who I have a good opinion of: - Raymond Hettinger: his presentation/teaching style is something I'd like to model my own after, also he gave the first talk on writing proper threaded/concurrent python that I was able to understand and make use of. - Brandon Rhoades: another speaker with a presentation style t…

dmvaldmanon Hacker News • Recommends

On “Y Not? – Adventures in Functional Programming (2012)”

This video (similar lecture, different audience) has the slides alongside the talk: link to this video Still one of the best programming talks I've ever seen.

caseyoharaon Hacker News • Recommends

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

On the same topic, Jim Weirich's 2012 talk "Y Not - Adventures in Functional Programming" on lambda calculus and the (little 'c') Y combinator is fantastic. link to this video

sva_on Hacker News • Recommends

On “Baking the Y Combinator from Scratch”

If anyone wants this in a humorous 1 hour format, watch the legendary Jim Weirich (rip) explain it here: link to this video Don't be discouraged that it is in Ruby as the concepts are completely general. Great watch even though I never coded a line of Ruby.

peterlkon Hacker News • Recommends

On “All elementary functions from a single binary operator”

Reminds me a bit of the coolest talk I ever got to see in person: link to this video It’s a derivation of the Y combinator from ruby lambdas

u/kinowin r/functionalprogramming • Recommends

Ruby Conf 12 - Y Not- Adventures in Functional Programming by Jim Weirich - YouTube

tesmar2on Hacker News • Recommends

On “Three Little Birds – Deriving the Y Combinator”

Jim Weirich derives the Y combinator in pure Ruby here: link EDIT: Correct video link to this video It is some of the ugliest ruby code I have ever seen, but it was something amazing to watch happen live.

al2o3cron Hacker News • Recommends

On “Emacs users are like Terry Pratchett’s Igors”

+1 on the lambda calculus stuff. Here's a related talk about deriving the Y combinator in Ruby by Jim Weirich: link to this video (skip to about 28:00 if you're impatient) There are additional versions of this same presentation circulating with the code in Javascript and (I believe) Clojure. Full disclosure: Jim is a co-worker of mine.

friendzison Hacker News • Recommends

On “Tech Talks”

Since it is not readme based, I suggest including Y-Not1 - an excellent talk about functional programming and lambda calculus 1: link to this video

HCIdivision17on Hacker News • Recommends

On “Excitement Over Gravity Waves Comes Crashing Down”

…It seems our universe follows certain equations which are themselves dimensionful, so I'm not sure why we wouldn't attempt to benchmark the universe against itself - we don't have much else to use. Even dimensionless numbers are only marginally useful, like alpha; it may "exist" and manifest as our universe, but it's not especially predictive. 0 link to this video (one of my favorite videos - I still don't grok it, but I'm getting closer!) 1 link…

pdkl95on Hacker News • Recommends

On “Ask HN: What's your favorite tech talk?”

Y Not - Adventures in Functional Programming by Jim Weirich link to this video The Coming Civil War over General Purpose Computing by Cory Doctorow link Cybersecurity as Realpolitik by Dan Geer link link

dnscoon Hacker News • Recommends

On “Deriving the Y Combinator in JavaScript”

Jim Weirich's 2012 Ruby Conf talk is also a great introduction to the Y Combinator and Lambda Calculus. link to this video