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Questions tagged [coproduct]

10 questions
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My coproduct encoding is ambiguous

This question has come up a few times recently, so I'm FAQ-ing it here. Suppose I've got some case classes like this: import io.circe._, io.circe.generic.semiauto._ object model { case class A(a: String) case class B(a: String, i: Int) case…
Travis Brown
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Existential type classes vs. Data Constructors vs. Coproducts

I find myself running up against the same pattern in my designs where I start with a type with a few data constructors, eventually want to be able to type against those data constructors and thus split them into their own types, just to then have to…
Francisco Ryan Tolmasky I
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GADT Type as Shapeless Coproduct -- how to build an Interpreter with an arbitrary number of Algebras

Let say I have two GADT types. abstract class Numbers[A]() case class IntType() extends Numbers[Int] abstract class Letters[A]() case class EnglishType() extends Letters[String] And I have an Interpreter for each of the GADT types which…
Travis Stevens
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3
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How to make only few datatype which is not related to each other acceptable by generics

There is a trait which works perfectly. However, I would like to refactor the part related to generic [T] in order to limit the data type which could be accepted by generic [T] (I need only Option[JsValue] , JsValue , StringEnumEntry , String ). Is…
Tim Florian
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How do I define value of discriminator for coproduct codecs?

Could you please explain how coproducts really work? Here is my code sealed trait ArdbData case class ArdbDataString(value: String) extends ArdbData case class ArdbDataLong(value: Long) extends ArdbData case class ArdbDataDouble(value: Double)…
expert
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Prepend more than two coproducts in Shapeless

I'd like to prepend more than two separate Coproducts into one: import shapeless.syntax._ case class Aa(name: String) case class Bb(age: Int) case class Cc(ok: Boolean) case class Dd(x: Long) case class Ee(y: Double) case class Ff(z:…
KaC
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Library for pattern matching shapeless coproduct with partial functions

I have a relatively ergonomic pattern I use to pattern match shapeless Coproducts. It looks basically like this val stringOrInt: String :+: Int :+: CNil = Coproduct("Hello world") implicit class Coproduct2Syntax[A, B](val value: A :+: B :+: CNil)…
kag0
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Shapeless: Iterate over the types in a Coproduct

I want to do something really simple, but I'm struggling to craft the correct search or just understanding some of the solutions I've seen. Given a method that takes a generic type parameter which is a Coproduct; def apply[T <: Coproduct] = { …
Ryan Worsley
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0
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Coproducts in shapeless does not compile

I'm experimenting with shapeless and now trying to understand Generic for Coproducts. Here is what I tried: object ShapelessExperiments { final case class Test1() final case class Test2() final case class Test3() type Test = Test1…
Some Name
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Get a specific implementation of a parametrized trait from a parametrized function

Trying to get a parametrized function that would return the specified coproduct of a trait. sealed trait Tr { def x: Int } case class Cl1(x: Int) extends Tr case class Cl2(x: Int) extends Tr def getTr[A <: Tr](i: Int): A = { ??? } How can this…
Vasily802
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