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by cassowary
3375 days ago
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really? It's been a while since I've programmed in Haskell, but something like this is about right: data Data = Data { thing :: Int, that :: Boolean }}
addToThing :: Int -> State Data Int
addToThing n = do
x <- get thing
modify (data -> data {thing: x + n})
return x
It corresponds to this Typescript code: class Data {
constructor(
private thing: number,
private that: Number
) {}
addToThing(n: number) {
const old = this.thing
this.thing = old + n
return old
}
}
Except for the fact that you only need to see mutation if you want to, and you certainly can't use the mutation unless you want it.To me it doesn't really look like jumping through hoops, but we're up front about the mutation so no-one's ever going to get a surprise. There's no silver bullet, sure. But I don't think pure FP is really all that complex. It's mostly just different. |
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I can't help but think that people who say this, yourself included, just don't deal with the problems that I face on a regular basis.
I write a lot of games and game engine code. I might have 60 dynamic objects in the game, each of which with its own behaviors, state and physics. Object oriented code means that the functionality for each object has both inherited and specialized behavior.
And when you're working with those dynamic objects, the "information hiding" aspect of OO programming can be very useful. Some objects have a member variable; others have an accessor that pulls the value out of a child class. I use that to good effect in my current game.
Or I might be parsing a map that I need to iterate over a rectangle in the map. But sometimes it's a hex map; ever tried to iterate over a hex map? Saying map.iterateRect(iterator, x,y,w,h) or equivalent, and not having to know whether the map is rectangular or hexagonal is very nice.
Functional programming is great when you have a lot of generic functions that you can apply to lots of different kinds of data. Object oriented programming ... is good for UI and game development, and anything else where the functions you're writing are very tailored to the data, where polymorphism can map well to the problem, and where you have lots of variations of kinds of data, but fewer (or less complex, or more specialized) things to do with the data.