I would say hat has more to do with Strongly Stati...

# arrow

[tmg]

I would say hat has more to do with Strongly Static Typed FP and it's advanced.
The most important parts are composition, immutability. and avoiding side-effects.

[julian]

@tmg Yes. I was actually just thinking I should revise what I said about learning FP to be more specific about learning an FP library like Arrow or Cats, which are both strongly typed FP.

[pakoito]

Compositionality is what keeps me being productive, even in imperative environments.

[julian]

@pakoito Can you unpack that statement a bit for me? Is compositionality so fundamental because it brings with it referential transparency and local reasoning?

[pakoito]

yes, it all goes hand in hand

[pakoito]

composing referentially transparent functions makes refactoring and modifying code easy, so I can move things around according to business needs really quickly

[pakoito]

local reasoning may not always be there, it's desirable and sometimes not up to you at all 🙂

[julian]

It's possible to have referential transparency without local reasoning? I never considered that before. Can you give an example?

[pakoito]

"what thread am I on right now"

[pakoito]

that's a frequent one

[pakoito]

or "what thread does this function happen on" downstream, if you prefer

[pakoito]

I can move the function from a map to a flatMap to a different place, to a result

[pakoito]

and I may not be able to reason whether it'd happened in this or that thread due to suspension or pieces like continueOn