Translating (+) <$> (*2) <*> (+10)

[THOUSAND-SKY]

(+) <$> [3] <*> [4] -- => [7] is pure (+) <*> [3] <*> [4]
and is translated to pipe([sum], array.ap([3]), array.ap([4])) // => [7].

But what is (+) <$> (*2) <*> (+10) translated to? What is pure (+) in this context?

[samhh]

I think that example relies on the applicative instance for (->). fp-ts-std defines these instances, for which the following appears to behave equivalently:

import { pipe } from 'fp-ts/function'
import * as Fn from 'fp-ts-std/Function'
import * as Num from 'fp-ts-std/Number'

export const f = pipe(
  Fn.of(Num.add),
  Fn.ap(Num.multiply(2)),
  Fn.ap(Num.add(10)),
)

Here pure (+) translates to Fn.of(Num.add).

[THOUSAND-SKY]

Very nice. Thank you.