Cooking with Monads

#functional #scala

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Oldest comments (3)

Iven Marquardt • May 13 '20 • Edited

Teaching monads by example may have its advantages but also entails its very own drawbacks. Monads are so general that every specific example you pick looks kind of arbitrarily, because you could have just as well picked another one from the thousands of possibilities.

Maybe it is a good idea to provide both, an example and an abstract decription: What a monad does on a very fundamental level is to turn an ordinary value into a computation of a specific notion. A mere collection of natural numbers [1,2,3], for instance, is turned into a prioritized choice/non deterministic computation. Actually Funtor does that already. Applicative and monads are just ways to sequence such computations. The former statically and the latter dynamically. Falling back to a fuzzy metaphor one can think of functor/applicative/monads as semantics machines or little embedded DSLs.

Andreas Jim • May 13 '20

Hi Iven, thanks a lot for your comment. I wrote this article back in 2016, when I was starting to seriously dive into functional programming – it was more of a test for myself, whether I understood the concepts well enough to write about them :) Having an imperative programming background, I struggled with the functional concepts; it took me a while to understand how the State monad works, for instance. It took me several months of hands-on experience to actually feel comfortable with monadic programming. To summarize – I'm not claiming that this article teaches anybody what a monad is, but maybe it can be a little bit helpful.