Merge pull request #1 from Ichoran/wip/cc2-cipt-internal-ev

Moved `Ev` from a generic type parameter to a member type in CIPT.

Author: szeiger

src/main/scala/strawman/collection/Iterable.scala

@@ -201,9 +201,11 @@ trait IterablePolyTransforms[+A, +C[A]] extends Any {
 /** Transforms over iterables that can return collections of different element types for which an
   * implicit evidence is required.
   */
-trait ConstrainedIterablePolyTransforms[+A, +C[A], +CC[X] <: C[X], Ev[A]] extends ConstrainedFromIterable[CC, Ev] with IterablePolyTransforms[A, C] {
+trait ConstrainedIterablePolyTransforms[+A, +C[A], +CC[X] <: C[X]] extends IterablePolyTransforms[A, C] {
+  type Ev[A]
 
   protected def coll: Iterable[A]
+  protected def constrainedFromIterable[B: Ev](it: Iterable[B]): CC[B]
 
   /** Map */
   def map[B : Ev](f: A => B): CC[B] = constrainedFromIterable(View.Map(coll, f))
@@ -218,6 +220,11 @@ trait ConstrainedIterablePolyTransforms[+A, +C[A], +CC[X] <: C[X], Ev[A]] extend
   def zip[B](xs: IterableOnce[B])(implicit ev: Ev[(A @uncheckedVariance, B)]): CC[(A @uncheckedVariance, B)] = constrainedFromIterable(View.Zip(coll, xs))
   // sound bcs of VarianceNote
 
+  def collect[B: Ev](pf: scala.PartialFunction[A, B]): CC[B] = flatMap(a => 
+    if (pf.isDefinedAt(a)) View.Elems(pf(a))
+    else View.Empty
+  )
+
   /** Widen this collection to the most specific unconstrained collection type. */
   def unconstrained: C[A @uncheckedVariance]
 }

src/main/scala/strawman/collection/SortedSet.scala

@@ -10,6 +10,9 @@ trait SortedSet[A]
 
 trait SortedSetLike[A, +C[X] <: SortedSet[X]]
   extends SortedLike[A, C[A]]
-    with ConstrainedIterablePolyTransforms[A, Set, SortedSet, Ordering]
+    with ConstrainedIterablePolyTransforms[A, Set, SortedSet]
     with SetLike[A, Set] // Inherited Set operations return a `Set`
-    with SetMonoTransforms[A, C[A]] // Override the return type of Set ops to return C[A]
+    with SetMonoTransforms[A, C[A]]// Override the return type of Set ops to return C[A]
+{
+  type Ev[A] = Ordering[A]
+}

src/main/scala/strawman/collection/immutable/SortedSet.scala

@@ -13,6 +13,7 @@ trait SortedSet[A]
 
 trait SortedSetLike[A, +C[X] <: SortedSet[X]]
   extends collection.SortedSetLike[A, C]
-    with ConstrainedIterablePolyTransforms[A, Set, C, Ordering]
+    with ConstrainedIterablePolyTransforms[A, Set, C]
     with SetLike[A, Set] // Inherited Set operations return a `Set`
     with SetMonoTransforms[A, C[A]] // Override the return type of Set ops to return C[A]
+    

src/main/scala/strawman/collection/mutable/SortedSet.scala

@@ -12,6 +12,6 @@ trait SortedSet[A]
 
 trait SortedSetLike[A, +C[X] <: SortedSet[X]]
   extends collection.SortedSetLike[A, C]
-    with ConstrainedIterablePolyTransforms[A, Set, SortedSet, Ordering]
+    with ConstrainedIterablePolyTransforms[A, Set, SortedSet]
     with SetLike[A, Set]
     with SetMonoTransforms[A, C[A]]