12:50 foldrStep alg recurse = alg . getCompose . fmap recurse . Compose . unList foldr alg = fix $ foldrStep alg

16:50 excessive strictness in the last line? should be: alg (Just v) r = case v of (x, xs) - > xs (f r x) -- so that you can never hit bottom before you apply r even for alg (Just undefined)? Or is that always impossible here?

for those who struggle with parsers/haskell in general, watch this course : kzfaq.info/sun/PL385J0eWxqYIJDIdG9KtP_JGLtgF0iKnj

Denoised version of The Algebra of Algebraic Data Types kzfaq.info/get/bejne/mM1gibWZvNTVZ3k.html&ab_channel=AlokSaldanha

Riveting presentation that goes on my list of very useful videos about functional programming

29:30 The polynomial expansion is valid for x<1. I wonder what that would mean for x as a list element...

oh, the happy days before the widespread singular they

Absolutely mind-blowing and beautiful, especially in the type calculus section. Thank you Chris Taylor.

Horrible sound

Good introduction. Enough to get started

There's another better version removing the terrible noise kzfaq.info/get/bejne/iKyCo7Wasr6Rd4E.html

Missed the event last night cos couldn't travel in from Cornwall. Will you be posting the vids soon?

I love seeing these kinds of projects finding more direct ways to handle incremental updates without a virtual DOM intermediary. (Like S.js/Surplus in JS for example.) I know Purescript Panda was just an exercise in that direction, but I bet the next framework to catch on after React will work this way.

This is so good! Life saver!

14:45 there's two too many mappend's in that mappend definition.

The talk is a very good primer and covers the more esoteric morphisms that are too often overlooked. I think negative comments on the speaker are without merit. Any serious study of the topic will require a dive into the literature, but the talk is a nice sampling, even if it is a bit of a whirlwind. Thank you, Tim Williams.

Does anyone know the paper (by someone named "top-") that he cites at 34'25"?

Yes I believe I do matter.

Ooo, using generics to write converters between domain objects is a cool idea!

Awesome talk! Great motivation and summaries.

If one uses the fact that the entries in row n of Pascal's triangle sum to 2^n (where we start counting at 0), the relationship for set becomes may be immediately obtained without "differencing".

Really great talk. If you want to know how far foldr and unfoldr can take you this talk is inspiring. Thanks, John Wiegley for recommending.

greeaaat. yet another crappppy sound monad video. it's like they doing it on purpose.

Talking about preparation... Sorry, that was very unprofessional.

I think this video is well worth its time, in spite of the errors in it. I have seen more knowledgable presentations, but they all went much too quickly into generalisations. Like the title suggests, here it is made clear why understanding the topic is worthwhile (in terms of some specific cases contained in those generalisations). In my own novice observations though, beyond the first two examples the code doesn't actually make use of the theory of monads (if that's the right word). Compose and id are defined, but don't ever contribute to code that is executed. AddP of the third example and runIO of the fourth implement the parts of compose they need for themselves, with direct reference to the structure of the monad - which misses the point entirely. Without promising that this is the standard, correct way of doing things, I can at least say that it would be an improvement to e g implement addP as addP ns ms = ns >>= ( -> ms >>= (\m -> return (n+m))) In order to get that to work, P should either be defined as a monad along with the functions (>>=) and return, or just be replaced with [Integer] (since list is a monad already). I wouldn't call it elegant, but at least the interaction with the structure of the monad is now kept out of this function.

such a bad presentation. do not waste your time with that crap. This guy is not only very poor prepaired, he seems not to know what he is talking about

my fav type error was an example by Bartosz Milewski: that Kafka character that turned into a roach.

The speaker needs to be using his active voice more, and stop saying "ahm" all the time.

YEAH Time to get to mars boys

Thank you so much! An amazing talk.

Awesome. I can't wait to try this out. Does it support signals and slots running on different threads as well?

the sporadic volume cuts make listening difficult.

That's good! I think, I got the point - for the first time!

no puedes hablar más despacio? no mames

love this lecture, we need intermediate to advanced level haskell talk. been fed up with "haskell introduction"...

beautiful newton's method in haskell indeed!

Excellent! Great job. Thanks.

I enjoyed the tutorial, it was truly useful. Thank you very much Chris Taylor.

Why are Nothing/Nil modeled as Unit/()/'1' rather than Void/Zed/Naught/'0' ?? Is this because they are the Empty Product, not Empty Sum? Are we therefore naming these wrong? Definitely blows my mind. So we map from the discrete types to the continuous real numbers, apply analysis (calculus), which transits territory that has no correspondence in discrete types, then take the result and map back to discrete types. WOW.

You should take the mike and shove / bind it to the range of whomever gave it to you, regarded as a function.

Great talk! Thanks!

So nuts and beautiful :)

I hate when people come late.

terrible sound :( love the content tho

Does his microphone have hiccups?

Wow!! Amazing talk!! This is the best explanation on the web! By far!

I believe the paper mentioned @34:20 *just as the audio goes out* is this one (which is linked to near the end of the 2nd of the 3 blog posts that go with this talk) arxiv.org/abs/math/0212377

8:53 Here he has defined *> twice and also has not implemented it.