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Monads are easy. They're just a design pattern that provides a formal abstraction over operation sequencing with additional computation. If you just accept them

Monads are easy. They're just a design pattern that provides a formal abstraction over operation sequencing with additional computation. If you just accept them as they are, rather than attempting to grok them by approaching them by analogy ("monads are like burritos"), you will make your life much easier. That's the secret to Haskell. There's no "getting it". There's just using it.

sshine 2y ago
I TA’ed a Haskell course for four years, and I came to the conclusion that what made it so difficult to learn was the apparent implicit mixup between newtype syntax / overloading and purpose of even using them. (The newtype syntax is necessary to differentiate between multiple instances of the typeclass; if you threw away the newtype syntax and overloading, >>= could only mean something for one thing, making it comprehensible but less useful — taking both steps at once loses most people.) Motivating the use of monads in FP requires solving a bunch of problems without, and realise your life would be so much easier if you abstracted out the commonality at the function composition level. But there isn’t time for that. When you skip the motivation, the explanation becomes “Welcome to FP. We’re gonna jump through these hoops because math is beautiful, also, most of the syntax you’re typing gets thrown away at compilation, good luck and fmap fmap fmap!”
vaylian 2y ago
> They're just a design pattern that provides a formal abstraction over operation sequencing with additional computation. You are right. But to someone who doesn't already know what a monad is, these words don't mean much, because they are very abstract. I personally started to understand monads when I learned why monads are useful. They are a tool. And if someone just hands you a tool without any explanation what to use the tool for, you will most likely not be able to do something with that tool. Monads are useful, because they make it possible to compose a sequence of computations in such a way, that failure/abortion anywhere in the sequence of computations is handled gracefully. This is relevant, because computer programs can fail all the time because of bad data or bad network connections. Monads allow for elegant error handling and fall-through.

sshine 2y ago

I TA’ed a Haskell course for four years, and I came to the conclusion that what made it so difficult to learn was the apparent implicit mixup between newtype syntax / overloading and purpose of even using them. (The newtype syntax is necessary to differentiate between multiple instances of the typeclass; if you threw away the newtype syntax and overloading, >>= could only mean something for one thing, making it comprehensible but less useful — taking both steps at once loses most people.) Motivating the use of monads in FP requires solving a bunch of problems without, and realise your life would be so much easier if you abstracted out the commonality at the function composition level. But there isn’t time for that. When you skip the motivation, the explanation becomes “Welcome to FP. We’re gonna jump through these hoops because math is beautiful, also, most of the syntax you’re typing gets thrown away at compilation, good luck and fmap fmap fmap!”

vaylian 2y ago

> They're just a design pattern that provides a formal abstraction over operation sequencing with additional computation. You are right. But to someone who doesn't already know what a monad is, these words don't mean much, because they are very abstract. I personally started to understand monads when I learned why monads are useful. They are a tool. And if someone just hands you a tool without any explanation what to use the tool for, you will most likely not be able to do something with that tool. Monads are useful, because they make it possible to compose a sequence of computations in such a way, that failure/abortion anywhere in the sequence of computations is handled gracefully. This is relevant, because computer programs can fail all the time because of bad data or bad network connections. Monads allow for elegant error handling and fall-through.