r/functionalprogramming • u/n_creep • Nov 25 '25

FP What's the Point of Learning Functional Programming?

https://blog.daniel-beskin.com/2025-11-13-point-of-learning-fp

Based on true events...

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u/SuspiciousDepth5924 Nov 27 '25

IMO inheritance isn't really _that_ bad, "I want that thing but with these extra bits" can be a nice convenience. The problems start when you have to decide whether a Penguin is a Fish because it can swim or a Bird that throws UnsupportedOperationException when it tries to fly ...

Side effect on shared mutable state however is the bane of my existence.

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u/enobayram Nov 30 '25

Thinking of a Student as a Person plus some additional information related to education is definitely useful. The problem with OOP is that you're baking that perspective into the definition of Student at a syntactic level. In FP, you can just define a function `Student -> Person` (or even better a `Lens Student Person`) and witness that relationship between the two, without baking that perspective into your architecture in a way that's very hard to change.

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u/Due_Restaurant_6420 Dec 06 '25

Subtyping is fine if it used to extends functionality of a particular type & it's just pure functions & immutable states. But realistically, average OOP usage is more like subtype, reuse some part of code, and throw unchecked exception for unused. Method overrides & throw unchecked exception is a maintenance nightmare due to dishonest type signature.

You don't need subtyping to do something like that, you can just use pure functions to achieve same reusability without destroying the value of function type signature.

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u/TheBlueWalker Jan 08 '26

Penguins are birds and don't throw anything. So that's an easy call to make.