To explain like two fundamental rules (we can make wrapper types, and do flatmap) I will:
- Write 5 paragraphs setting up an imaginary scenario involving fantasy elements of aliens, dragons, and a magical kindom where they speak using message boxes
- Introduce basic category theory by starting with what a functor is
- Explain all the effects of a monad in such general terms that it basically amounts to anything and everything - since a function can be anything and do everything and it's just function composition
- Write some snippets of Haskell, and just assume that you're familiar with the syntax
I've read more than my fair share of these tutorials, and I'd like to be proven wrong here but I don't think I've ever seen one that explains what the point of these functional constructs (similarly with Applicative etc.) is.
"You can do IO now." So what? I could do IO before that as well.
Very rarely are practical explanations discussed. Even if they are discussed, the treatment is shallow and useless.
From the very beginning of the article (level 1), I don't see what's wrong with code that looks like the following. Early return seems to fix the "typing this makes me feel ill" part? To me, the following code seems perfectly readable without requiring the reader to know about function composition.
I find that pretty repetitive, but more, having to reason about branching control flow adds a lot of mental overhead that I'd rather spend on my business logic.
From my experience having used Haskell (a long time ago), the main benefit of Monads is the `do` and <- syntax. Once you got your thing to satisfy the Monad interface, you unlocked the nice syntax for writing code. That, and compatibility with transformers.
Whether this is the best thing since sliced bread or not, is left as an exercise to the reader.
Monads got their name from monoids (being a monoid in the category of endofunctors). Monoids are equivalent to one-object categories, so the name uses the greek syllable "mono" for one.
I understood the monad concept for a few months in university. After the exam was over, I soon stopped understanding it. The same thing happened with the concept of VC dimension. It's kind of interesting, because we usually don't think of "understanding" as something that comes with a time limit.
It happens all the time. For a brief period I understood musical notation and rhythm and then it was gone. Similarly I had a time in my life where I knew by feeling whether a French noun was le or la.
I've spent a lot of time wrapping my head around monads; whenever I thought I "got it," I would come across some exotic monad that completely blew my mind. The best way to understand them is not to rely on analogies but just follow the rules—everybody says that, but it took me a while to truly realize it.
I tried understanding the rules but actually using it helped me to get it. Especially when I was using a parser combinator to parse a programming language.
To explain like two fundamental rules (we can make wrapper types, and do flatmap) I will:
- Write 5 paragraphs setting up an imaginary scenario involving fantasy elements of aliens, dragons, and a magical kindom where they speak using message boxes
- Introduce basic category theory by starting with what a functor is
- Explain all the effects of a monad in such general terms that it basically amounts to anything and everything - since a function can be anything and do everything and it's just function composition
- Write some snippets of Haskell, and just assume that you're familiar with the syntax
- Talk about how delicious burritos are
I've read more than my fair share of these tutorials, and I'd like to be proven wrong here but I don't think I've ever seen one that explains what the point of these functional constructs (similarly with Applicative etc.) is.
"You can do IO now." So what? I could do IO before that as well.
Very rarely are practical explanations discussed. Even if they are discussed, the treatment is shallow and useless.
Here's my effort: https://m50d.github.io/2013/01/16/generic-contexts
From the very beginning of the article (level 1), I don't see what's wrong with code that looks like the following. Early return seems to fix the "typing this makes me feel ill" part? To me, the following code seems perfectly readable without requiring the reader to know about function composition.
I find that pretty repetitive, but more, having to reason about branching control flow adds a lot of mental overhead that I'd rather spend on my business logic.
From my experience having used Haskell (a long time ago), the main benefit of Monads is the `do` and <- syntax. Once you got your thing to satisfy the Monad interface, you unlocked the nice syntax for writing code. That, and compatibility with transformers.
Whether this is the best thing since sliced bread or not, is left as an exercise to the reader.
Haskell is primarily a bunch of type gymnastics designed to give the impression of "purity" when no such thing exists in the world.
I still don’t understand why it’s named from Gnosticism (https://en.wikipedia.org/wiki/Monad_(Gnosticism))
Monads got their name from monoids (being a monoid in the category of endofunctors). Monoids are equivalent to one-object categories, so the name uses the greek syllable "mono" for one.
It comes from Pythagoras, not Gnosticism
Yeah, would like to know as well. I think the applicative functor was originally call "Idiom", another weird name.
It's an updating wiki.. but (2017) https://news.ycombinator.com/item?id=15170328
Popular well.. submissions in:
2019 (3 points) https://news.ycombinator.com/item?id=19207241
2022 (3 points) https://news.ycombinator.com/item?id=30277518
2024 (11 points) https://news.ycombinator.com/item?id=40332349
I understood the monad concept for a few months in university. After the exam was over, I soon stopped understanding it. The same thing happened with the concept of VC dimension. It's kind of interesting, because we usually don't think of "understanding" as something that comes with a time limit.
It happens all the time. For a brief period I understood musical notation and rhythm and then it was gone. Similarly I had a time in my life where I knew by feeling whether a French noun was le or la.
Pretty cool!
I've spent a lot of time wrapping my head around monads; whenever I thought I "got it," I would come across some exotic monad that completely blew my mind. The best way to understand them is not to rely on analogies but just follow the rules—everybody says that, but it took me a while to truly realize it.
See, for example, the Tardis monad or the Cont monad: https://www.reddit.com/r/haskell/comments/446d13/exotic_mona...
I tried understanding the rules but actually using it helped me to get it. Especially when I was using a parser combinator to parse a programming language.
So weird, on the front page at the same time as this: "Biology is a burrito"
When I saw that link it immediately reminded me of this: https://blog.plover.com/prog/burritos.html
>Monads are like burritos
And then a few links down is this link to monad tutorials.
Weird coincidence.
> Monads are like burritos https://blog.plover.com/prog/burritos.html
I'm surprised that this tutorial isn't on the wiki.