test for t0716
git-svn-id: http://lampsvn.epfl.ch/svn-repos/scala/scala/trunk@14495 5e8d7ff9-d8ef-0310-90f0-a4852d11357a
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trait Functor[F[_]] {
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def fmap[A,B](fun: A=>B, arg:F[A]): F[B]
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}
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object Functor{
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implicit val ListFunctor = new Functor[List] {
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def fmap[A, B](f: A => B, arg: List[A]):List[B] = arg map f
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}
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final class OOFunctor[F[_],A](arg:F[A])(implicit ftr: Functor[F]) {
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def fmap[B](fun: A=>B):F[B] = ftr.fmap(fun,arg)
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}
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//breaks if uncommented
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implicit def lifttoOO[F[_],A](arg:F[A])(implicit ftr: Functor[F]) = new OOFunctor[F,A](arg)(ftr)
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//works if uncommented
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//implicit def liftListtoOO[A](arg:List[A]):OOFunctor[List,A] = new OOFunctor[List,A](arg)
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}
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object GeneralLiftingDemo extends Application {
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import Functor._
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val l = List(1,2,3)
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println("OO : " + l.fmap( 1+) )
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}
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