Created
July 6, 2015 08:37
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| trait LeftFolder[C <: Coproduct, In, F] extends Serializable { | |
| def apply(c: C, in: In): In | |
| } | |
| object LeftFolder { | |
| def apply[C <: Coproduct, In, F](implicit folder: LeftFolder[C, In, F]) = folder | |
| implicit def hdLeftFolder[H, T <: Coproduct, In, F] | |
| (implicit f: Case2.Aux[F, In, H, In]): LeftFolder[H :+: T, In, F] = new LeftFolder[H :+: T, In, F] { | |
| def apply(c: H :+: T, in: In): In = c match { | |
| case Inl(h) => f(in, h) | |
| case Inr(t) => in | |
| } | |
| } | |
| implicit def tlLeftFolder[H, T <: Coproduct, In, F] | |
| (implicit st: LeftFolder[T, In, F]): LeftFolder[H :+: T, In, F] = new LeftFolder[H :+: T, In, F] { | |
| def apply(c: H :+: T, in: In) = | |
| c match { | |
| case Inl(h) => in | |
| case Inr(t) => st(t,in) | |
| } | |
| } | |
| } |
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