Traversable view conversion

[amasson88]

hi

Thanks for this nice library! Exactly what I was looking for :)

I have found a small issue. There is some implicit conversion in v0.1.2 from Traversable(View) that doesn't preserve laziness.

For example

  val source = new Traversable[String] {
      def foreach[U](f: String => U): Unit = {
        println("emit V1")
        f("V1")
        println("emit V2")
        f("V2")
        println("emit V3")
        f("V3")
      }
    }    
    val gen: Generator[String] = source.view    
    gen.foreach { x => println("foreach " + x) }

gives:

emit V1
emit V2
emit V3
foreach V1
foreach V2
foreach V3

As a workaround, something like this seems to work:

    def fromLazyTrav[T](trav: Traversable[T]) = new Generator[T] {
      import Generator._
      def generate(f: T => Action): Action = {
        trav.foreach { x =>
          val r = f(x)
          if (r == End) return End
        }
        Continue
      }
    }
...
    val gen = fromLazyTrav(source)
    gen.foreach { x => println("foreach " + x) }

It gives:

emit V1
foreach V1
emit V2
foreach V2
emit V3
foreach V3

Would it be possible to preserve laziness by default?

thanks
Arnaud

[Li Haoyi]

Views are deprecated so probably not gonna bother