Add doctest for IdT
#4445
Add doctest for IdT
#4445
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| * scala> import cats.~> | ||
| * scala> import cats.data.IdT | ||
| * | ||
| * scala> val vectorToList: Vector ~> List = new ~>[Vector, List] { override def apply[A](v: Vector[A]): List[A] = v.toList } |
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This part can be simplified :
| * scala> val vectorToList: Vector ~> List = new ~>[Vector, List] { override def apply[A](v: Vector[A]): List[A] = v.toList } | |
| * scala> val vectorToList: Vector ~> List = FunctionK.liftFunction(_.toList) |
(requires import cats.arrow.FunctionK)
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(for Scala3 the syntax is going to be slightly different though)
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Sure, it could have written it that way, I just wrote it in detail so that anybody could fully see how it happens)
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Well, I'm leaning to think that examples in scaladocs should keep the examples as simple as possible. Whereas the details on how, let's say, FunctionK works is supposed to be captured in the FunctionK scaladocs per se.
But I don't think it's really worth bikeshedding anyway – in any case it is a great job on providing the missing docs for the class, thank you for doing this!
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I'm not sure if we can write it like that, don't the doctests have to cross-compile for Scala 2 and Scala 3? So we are stuck with worst-of-both-worlds syntax.
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Thank you for the PR! Looks good to me in general, the only nit is regarding mapK: I think it would make sense to show a simplified FunctionK syntax in the examples. |
| * scala> import cats.data.IdT | ||
| * | ||
| * scala> val idT: IdT[List, Int] = IdT(List(1, 2, 3)) | ||
| * scala> idT.flatMap(x => IdT(List(x + 1))) |
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A more interesting demo of flatMap might do something like this. Otherwise it's a glorified map 😉
| * scala> idT.flatMap(x => IdT(List(x + 1))) | |
| * scala> idT.flatMap(x => IdT(List(x + 1, x + 2))) |
| * scala> import cats.data.IdT | ||
| * | ||
| * scala> val idT: IdT[List, Int] = IdT(List(1, 2, 3)) | ||
| * scala> idT.flatMapF(x => List(Option(x).filter(_ % 2 == 0))) |
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Same with this one, it's basically just demoing a map. Actually, I'd do the example without the Option, it's a bit distracting IMO.
PR for part of #2479
Adding doctest for IdT typeclass.