无形中是否有将类型构造函数用于 Nat 的基础结构? [英] Is there infrastructure in shapeless that takes a type constructor to the power of a Nat?

问题描述

对我来说，这似乎是一个非常基本的功能，但我在当前的 shapeless (2.3.3) 中找不到它.

To me this appears as a very basic functionality, but I can't find it in current shapeless (2.3.3).

所以我正在寻找一个类型 Induction[X,F[_],N <: Nat] with

So I am looking for a type Induction[X,F[_],N <: Nat] with

Induction[X,F,Nat._0].Out =:= X
Induction[X,F,Nat._1].Out =:= F[X]
Induction[X,F,Nat._2].Out =:= F[F[X]]
...

也许也可以沿着类型构造链接一个函数，例如，构造一个 Point 实例?

Maybe it's also possible to chain a function along the type construction, e.g., to construct a Point instance?

推荐答案

不，没有.正如您所观察到的，这很可能需要一个类似 Point 的类型类才能有用.我建议在 Kittens 中添加类似的内容，这取决于无形和猫.

No there isn't. As you observe this most likely needs a Point-like type class to be useful. I suggest adding something like this to Kittens which depends on both shapeless and Cats.

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