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0 pointsmrkeen1y ago0 comments

That's right, but only because it's a 1-to-many comparison error.

Callbacks are one particular monad, not monads in general: https://jsdw.me/posts/haskell-cont-monad/

0 comments

But then CPS machinery is often used to implement Monads.

> Programming with monads strongly reminiscent of continuation—passing style (CPS), and this paper explores the relationship between the two. In a sense they are equivalent: CPS arises as a special case of a monad, and any monad may be embedded in CPS by changing the answer type.

https://cs.uwaterloo.ca/~david/cs442/monads.pdf

bazoom421y ago

Promises in JavaScript are not monads as far as I can tell. While they have a somewhat similar interface, they do not appear to obey the monad laws.

explaininjs1y ago

There is one particular edge case in which they do not satisfy the laws. That happens to make them much more practical in day to day coding than a strict interpretation would be.

bazoom421y ago

So having Promises be monads would make them less useful? This is an interesting point.

It seems to confirm the argument that monads are not that useful or pervasive outside of Haskell.

1 more reply

acchow1y ago

I was not actually thinking of Javascript (or any particular language) when I mentioned async-await. I was just referring to the concept.

j / k navigate · click thread line to collapse

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dumbo-octopus1y ago

But then CPS machinery is often used to implement Monads.

https://cs.uwaterloo.ca/~david/cs442/monads.pdf

bazoom421y ago

Promises in JavaScript are not monads as far as I can tell. While they have a somewhat similar interface, they do not appear to obey the monad laws.

explaininjs1y ago

There is one particular edge case in which they do not satisfy the laws. That happens to make them much more practical in day to day coding than a strict interpretation would be.

bazoom421y ago

So having Promises be monads would make them less useful? This is an interesting point.

It seems to confirm the argument that monads are not that useful or pervasive outside of Haskell.

1 more reply

acchow1y ago

I was not actually thinking of Javascript (or any particular language) when I mentioned async-await. I was just referring to the concept.

j / k navigate · click thread line to collapse