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  • g

    girafferson

    04/24/2018, 12:17 AM
    Let me pull up the arrow source again
  • p

    pakoito

    04/24/2018, 12:17 AM
    @pakoito uploaded a file: Untitled
    Untitled.txt
  • p

    pakoito

    04/24/2018, 12:18 AM
    you see two generics there
  • p

    pakoito

    04/24/2018, 12:18 AM
    the generic in the interface refers to the container
  • p

    pakoito

    04/24/2018, 12:18 AM
    but the generic in the function refers to the content
  • p

    pakoito

    04/24/2018, 12:19 AM
    which means that the implementation of this interface has to work for all objects of the container F, regardless of the type of its content
  • p

    pakoito

    04/24/2018, 12:19 AM
    let’s create one implementation
  • p

    pakoito

    04/24/2018, 12:20 AM
    @pakoito uploaded a file: Untitled
    Untitled.txt
  • p

    pakoito

    04/24/2018, 12:20 AM
    and we can use it for lists of any type
  • p

    pakoito

    04/24/2018, 12:21 AM
    @pakoito uploaded a file: Untitled
    -.txt
  • g

    girafferson

    04/24/2018, 12:22 AM
    Okay yeah I think that makes sense
  • g

    girafferson

    04/24/2018, 12:22 AM
    So last thing
  • g

    girafferson

    04/24/2018, 12:22 AM
    like, functions like fix(), I'll read it then forget about it
  • g

    girafferson

    04/24/2018, 12:22 AM
    Idk what fix does
  • p

    pakoito

    04/24/2018, 12:22 AM
    yes, I was expecting that question
  • g

    girafferson

    04/24/2018, 12:23 AM
    😛
  • p

    pakoito

    04/24/2018, 12:23 AM
    to be able to generify over containers
  • p

    pakoito

    04/24/2018, 12:23 AM
    we need a language feature that Kotlin doens’t have
  • p

    pakoito

    04/24/2018, 12:23 AM
    so we emulate it instead
  • p

    pakoito

    04/24/2018, 12:23 AM
    lemme show you a small snippet and tell me if it makes sense
  • p

    pakoito

    04/24/2018, 12:24 AM
    @pakoito uploaded a file: Untitled
    Untitled.txt
  • g

    girafferson

    04/24/2018, 12:25 AM
    It makes sense to me in the context of fix
  • p

    pakoito

    04/24/2018, 12:25 AM
    so what fix is, first
  • p

    pakoito

    04/24/2018, 12:25 AM
    it is an extension function
  • p

    pakoito

    04/24/2018, 12:25 AM
    that requires one generic parameter to be fixed to an existing value
  • p

    pakoito

    04/24/2018, 12:25 AM
    in this case is ForList
  • g

    girafferson

    04/24/2018, 12:26 AM
    Right
  • p

    pakoito

    04/24/2018, 12:26 AM
    what it does, is, because Kind<ForList, A> can only be a ListK<A> because that’s the only implementor of Kind<ForList, A>, you can downcast safely
  • p

    pakoito

    04/24/2018, 12:27 AM
    ForList
    here is a non-instanciable class with a private constructor
  • p

    pakoito

    04/24/2018, 12:27 AM
    its only purpose is to be a marker for this and other extension functions and interfaces
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