Functors, Applicatives, and Monads: You don't need to know theory to use them

http://joyfulmantis.github.io/posts/2017-08-23-functors-applicatives-monads.html

by joyfulmantis • 9 years ago

4 4 9 years ago

joyfulmantis.github.io

catnaroek2• 9 years ago

Nothing about laws? Seriously? The laws are the entire point! (Even if some socially maladjusted people occasionally break them.)

joyfulmantis• 9 years ago

The laws are important if you want to implement these typeclasses in your own data type, but I feel for new comers who will only want to use them in other data types it is better to first focus on practical application. I feel that laws and formal definitions tend to drive away newcomers from a subject that need not be so hard to understand.

catnaroek2• 9 years ago

Sorry, joyfulmantis, your comment appears “dead”, so I can't directly reply to it.

Haskell's standard type classes represent algebraic structures. And to understand algebraic structures, you need the axioms that define them. There is no way around this. Of course, you also need examples, but they are by no means a replacement for definitions. If you don't understand the definitions, then you don't understand the abstraction at all.

hakonrossebo• 9 years ago

Really like the practical approach of explaining these concepts.

Functors, Applicatives, and Monads: You don't need to know theory to use them

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