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January 5, 2017 14:10
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| /** | |
| * Created by ariwaranosai on 2017/1/3. | |
| * | |
| */ | |
| trait ExpAlg[T] { | |
| def lit(n: Int): T | |
| def add(x: T, y: T): T | |
| } | |
| object ExpAlg { | |
| implicit def toIntExpOps[T](n: Int)(implicit m: ExpAlg[T]): ToIntExpOps[T] = | |
| new ToIntExpOps[T](n)(m) | |
| class ToIntExpOps[T](n: Int)(implicit m: ExpAlg[T]) { | |
| def lit[T](implicit m: ExpAlg[T]): T = m.lit(n) | |
| } | |
| implicit def toExpAlgTOps[T](n: T)(implicit m: ExpAlg[T]) = | |
| new ToExpAlgTOps[T](n)(m) | |
| class ToExpAlgTOps[T](n: T)(implicit m: ExpAlg[T]) { | |
| def add(y: T): T = m.add(n, y) | |
| def ++ = add _ | |
| } | |
| } | |
| trait MulAlg[T] { | |
| def mul(x: T, y: T): T | |
| } | |
| object MulAlg { | |
| implicit def toMulAlgOps[T](n: T)(implicit m: MulAlg[T]) = | |
| new ToMulAlgOps[T](n)(m) | |
| class ToMulAlgOps[T](n: T)(m: MulAlg[T]) { | |
| def mul(y: T): T = m.mul(n, y) | |
| def ** = mul _ | |
| } | |
| } | |
| trait Eval { | |
| def eval: Int | |
| } | |
| import ExpAlg._ | |
| import MulAlg._ | |
| object EvalInstance { | |
| implicit val evalInstance = new ExpAlg[Eval] { | |
| override def lit(n: Int) = new Eval { | |
| override def eval = n | |
| } | |
| override def add(x: Eval, y: Eval) = new Eval { | |
| override def eval = x.eval + y.eval | |
| } | |
| } | |
| implicit val mulInstance = new MulAlg[Eval] { | |
| override def mul(x: Eval, y: Eval): Eval = new Eval { | |
| override def eval = x.eval * y.eval | |
| } | |
| } | |
| } | |
| object FTT { | |
| def main(args: Array[String]): Unit = { | |
| def e1[T](implicit m: ExpAlg[T]) = { | |
| (1.lit[T] ++ 2.lit[T]) ++ 2.lit[T] | |
| } | |
| def e2[T](implicit m: ExpAlg[T], m1: MulAlg[T]) = { | |
| (1.lit[T] ++ 2.lit[T]) ** 3.lit[T] | |
| } | |
| import EvalInstance._ | |
| println(e1[Eval].eval) | |
| println(e2[Eval].eval) | |
| } | |
| } | |
| trait View { | |
| def view: String | |
| } | |
| object ViewExp { | |
| implicit val viewInstance = new ExpAlg[View] { | |
| override def lit(n: Int): View = new View { | |
| override def view = n.toString | |
| } | |
| override def add(x: View, y: View): View = new View { | |
| override def view = s"(${x.view} + ${y.view})" | |
| } | |
| } | |
| implicit val mulInstance = new MulAlg[View] { | |
| override def mul(x: View, y: View): View = new View { | |
| override def view = s"(${x.view} * ${y.view})" | |
| } | |
| } | |
| } | |
| object FTT1 { | |
| def main(args: Array[String]): Unit = { | |
| def e1[T](implicit m: ExpAlg[T]) = { | |
| (1.lit[T] ++ 2.lit[T]) ++ 2.lit[T] | |
| } | |
| def e2[T](implicit m: ExpAlg[T], m1: MulAlg[T]) = { | |
| (1.lit[T] ++ 2.lit[T]) ** 3.lit[T] | |
| } | |
| import ViewExp._ | |
| println(e1[View].view) | |
| println(e2[View].view) | |
| } | |
| } | |
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