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Merged
merged 17 commits into from
Aug 14, 2016
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Add arrays to collection strawman #1414

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0c489f5
Add arrays to collection strawman
odersky Jul 25, 2016
84466af
Further extension with LazyList
odersky Jul 26, 2016
568e489
Improve drop
odersky Jul 27, 2016
0d44e9e
Fix substDealias
odersky Jul 27, 2016
aa0bf12
Rename fromLikeIterable -> fromIterableWithSameElemType
odersky Jul 27, 2016
2e72590
Fix problem related to cbn parameters in supercalls
odersky Jul 27, 2016
2af7ea0
Move test from pos to run
odersky Jul 27, 2016
d7b1c0e
Quick-fix eclosingMethod attribute generation for t3048.scala
DarkDimius Jul 27, 2016
87cff22
Simplify lexicallyEnclosingClass
odersky Jul 27, 2016
a591802
Make colltest6 self-contained
odersky Jul 27, 2016
09b81e5
Tweaks to strawman
odersky Jul 28, 2016
9ab6ce7
Drop on LinearSeq needs to return collection of same type as it was c…
odersky Jul 29, 2016
2902000
Index members of a class before evaluating its parents
odersky Jul 29, 2016
dabf044
Print kind of missing member
odersky Jul 29, 2016
8db8c11
More systematic treatement of IndexedView
odersky Jul 30, 2016
d88a280
Fix problem with IndexedView.iterator.length
odersky Jul 31, 2016
4e95a10
Add missing import
odersky Jul 31, 2016
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87 changes: 61 additions & 26 deletions src/strawman/collections/CollectionStrawMan6.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -116,14 +116,17 @@ object CollectionStrawMan6 extends LowPriority {
trait Iterable[+A] extends IterableOnce[A] with IterableLike[A, Iterable] {
/** The collection itself */
protected def coll: this.type = this
}
}

/** Base trait for sequence collections */
trait Seq[+A] extends Iterable[A] with SeqLike[A, Seq] {
def apply(i: Int): A
/** A trait representing indexable collections with finite length */
trait ArrayLike[+A] extends Any {
def length: Int
def apply(i: Int): A
}

/** Base trait for sequence collections */
trait Seq[+A] extends Iterable[A] with SeqLike[A, Seq] with ArrayLike[A]

/** Base trait for linearly accessed sequences that have efficient `head` and
* `tail` operations.
* Known subclasses: List, LazyList
Expand Down Expand Up @@ -156,6 +159,8 @@ object CollectionStrawMan6 extends LowPriority {
}
}

type IndexedSeq[+A] = Seq[A] { def view: IndexedView[A] }
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If you do this then any call to view on a value with type IndexedSeq[Foo] will end up going through reflection, no?

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On Sun, Jul 31, 2016 at 12:07 AM, Guillaume Martres <
[email protected]> wrote:

In src/strawman/collections/CollectionStrawMan6.scala
#1414 (comment):

@@ -156,6 +159,8 @@ object CollectionStrawMan6 extends LowPriority {
}
}

  • type IndexedSeq[+A] = Seq[A] { def view: IndexedView[A] }

If you do this then any call to view on a value with type IndexedSeq[Foo]
will end up going through reflection, no?

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.

I don't think so, since view is already a method on Seq.


/** Base trait for strict collections that can be built using a builder.
* @param A the element type of the collection
* @param Repr the type of the underlying collection
Expand Down Expand Up @@ -593,6 +598,7 @@ object CollectionStrawMan6 extends LowPriority {
}

class ArrayBufferView[A](val elems: Array[AnyRef], val start: Int, val end: Int) extends IndexedView[A] {
def length = end - start
def apply(n: Int) = elems(start + n).asInstanceOf[A]
override def className = "ArrayBufferView"
}
Expand Down Expand Up @@ -656,7 +662,8 @@ object CollectionStrawMan6 extends LowPriority {
extends AnyVal with IterableOps[Char]
with SeqMonoTransforms[Char, String]
with IterablePolyTransforms[Char, List]
with Buildable[Char, String] {
with Buildable[Char, String]
with ArrayLike[Char] {

protected def coll = new StringView(s)
def iterator = coll.iterator
Expand All @@ -671,6 +678,9 @@ object CollectionStrawMan6 extends LowPriority {

protected[this] def newBuilder = new StringBuilder

def length = s.length
def apply(i: Int) = s.charAt(i)

override def knownSize = s.length

override def className = "String"
Expand Down Expand Up @@ -720,8 +730,7 @@ object CollectionStrawMan6 extends LowPriority {
}

case class StringView(s: String) extends IndexedView[Char] {
val start = 0
val end = s.length
def length = s.length
def apply(n: Int) = s.charAt(n)
override def className = "StringView"
}
Expand All @@ -731,11 +740,15 @@ object CollectionStrawMan6 extends LowPriority {
implicit class ArrayOps[A](val xs: Array[A])
extends AnyVal with IterableOps[A]
with SeqMonoTransforms[A, Array[A]]
with Buildable[A, Array[A]] {
with Buildable[A, Array[A]]
with ArrayLike[A] {

protected def coll = new ArrayView(xs)
def iterator = coll.iterator

def length = xs.length
def apply(i: Int) = xs.apply(i)

override def view = new ArrayView(xs)

def elemTag: ClassTag[A] = ClassTag(xs.getClass.getComponentType)
Expand All @@ -757,8 +770,7 @@ object CollectionStrawMan6 extends LowPriority {
}

case class ArrayView[A](xs: Array[A]) extends IndexedView[A] {
val start = 0
val end = xs.length
def length = xs.length
def apply(n: Int) = xs(n)
override def className = "ArrayView"
}
Expand Down Expand Up @@ -822,15 +834,17 @@ object CollectionStrawMan6 extends LowPriority {
/** A view that drops leading elements of the underlying collection. */
case class Drop[A](underlying: Iterable[A], n: Int) extends View[A] {
def iterator = underlying.iterator.drop(n)
protected val normN = n max 0
override def knownSize =
if (underlying.knownSize >= 0) underlying.knownSize - n max 0 else -1
if (underlying.knownSize >= 0) (underlying.knownSize - normN) max 0 else -1
}

/** A view that takes leading elements of the underlying collection. */
case class Take[A](underlying: Iterable[A], n: Int) extends View[A] {
def iterator = underlying.iterator.take(n)
protected val normN = n max 0
override def knownSize =
if (underlying.knownSize >= 0) underlying.knownSize min n else -1
if (underlying.knownSize >= 0) underlying.knownSize min normN else -1
}

/** A view that maps elements of the underlying collection. */
Expand Down Expand Up @@ -872,29 +886,51 @@ object CollectionStrawMan6 extends LowPriority {
}

/** View defined in terms of indexing a range */
trait IndexedView[+A] extends View[A] { self =>
def start: Int
def end: Int
def apply(i: Int): A
trait IndexedView[+A] extends View[A] with ArrayLike[A] {

def iterator: Iterator[A] = new Iterator[A] {
private var current = start
def hasNext = current < end
private var current = 0
def hasNext = current < length
def next: A = {
val r = apply(current)
current += 1
r
}
}

def reverse = new IndexedView[A] {
def start = self.start
def end = self.end
def apply(i: Int) = self.apply(end - 1 - i)
override def take(n: Int): IndexedView[A] = new IndexedView.Take(this, n)
override def drop(n: Int): IndexedView[A] = new IndexedView.Drop(this, n)
override def map[B](f: A => B): IndexedView[B] = new IndexedView.Map(this, f)
def reverse: IndexedView[A] = new IndexedView.Reverse(this)
}

object IndexedView {

class Take[A](underlying: IndexedView[A], n: Int)
extends View.Take(underlying, n) with IndexedView[A] {
override def iterator = super.iterator
def length = underlying.length min normN
def apply(i: Int) = underlying.apply(i)
}

def length = end - start max 0
override def knownSize = length
class Drop[A](underlying: IndexedView[A], n: Int)
extends View.Take(underlying, n) with IndexedView[A] {
override def iterator = super.iterator
def length = (underlying.length - normN) max 0
def apply(i: Int) = underlying.apply(i + normN)
}

class Map[A, B](underlying: IndexedView[A], f: A => B)
extends View.Map(underlying, f) with IndexedView[B] {
override def iterator = super.iterator
def length = underlying.length
def apply(n: Int) = f(underlying.apply(n))
}

case class Reverse[A](underlying: IndexedView[A]) extends IndexedView[A] {
def length = underlying.length
def apply(i: Int) = underlying.apply(length - 1 - i)
}
}

/* ---------- Iterators ---------------------------------------------------*/
Expand Down Expand Up @@ -1002,8 +1038,7 @@ object CollectionStrawMan6 extends LowPriority {
def next = throw new NoSuchElementException("next on empty iterator")
}
def apply[A](xs: A*): Iterator[A] = new IndexedView[A] {
val start = 0
val end = xs.length
val length = xs.length
def apply(n: Int) = xs(n)
}.iterator
}
Expand Down
87 changes: 61 additions & 26 deletions tests/run/colltest6/CollectionStrawMan6_1.scala
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -117,14 +117,17 @@ object CollectionStrawMan6 extends LowPriority {
trait Iterable[+A] extends IterableOnce[A] with IterableLike[A, Iterable] {
/** The collection itself */
protected def coll: this.type = this
}
}

/** Base trait for sequence collections */
trait Seq[+A] extends Iterable[A] with SeqLike[A, Seq] {
def apply(i: Int): A
/** A trait representing indexable collections with finite length */
trait ArrayLike[+A] extends Any {
def length: Int
def apply(i: Int): A
}

/** Base trait for sequence collections */
trait Seq[+A] extends Iterable[A] with SeqLike[A, Seq] with ArrayLike[A]

/** Base trait for linearly accessed sequences that have efficient `head` and
* `tail` operations.
* Known subclasses: List, LazyList
Expand Down Expand Up @@ -157,6 +160,8 @@ object CollectionStrawMan6 extends LowPriority {
}
}

type IndexedSeq[+A] = Seq[A] { def view: IndexedView[A] }

/** Base trait for strict collections that can be built using a builder.
* @param A the element type of the collection
* @param Repr the type of the underlying collection
Expand Down Expand Up @@ -594,6 +599,7 @@ object CollectionStrawMan6 extends LowPriority {
}

class ArrayBufferView[A](val elems: Array[AnyRef], val start: Int, val end: Int) extends IndexedView[A] {
def length = end - start
def apply(n: Int) = elems(start + n).asInstanceOf[A]
override def className = "ArrayBufferView"
}
Expand Down Expand Up @@ -657,7 +663,8 @@ object CollectionStrawMan6 extends LowPriority {
extends AnyVal with IterableOps[Char]
with SeqMonoTransforms[Char, String]
with IterablePolyTransforms[Char, List]
with Buildable[Char, String] {
with Buildable[Char, String]
with ArrayLike[Char] {

protected def coll = new StringView(s)
def iterator = coll.iterator
Expand All @@ -672,6 +679,9 @@ object CollectionStrawMan6 extends LowPriority {

protected[this] def newBuilder = new StringBuilder

def length = s.length
def apply(i: Int) = s.charAt(i)

override def knownSize = s.length

override def className = "String"
Expand Down Expand Up @@ -721,8 +731,7 @@ object CollectionStrawMan6 extends LowPriority {
}

case class StringView(s: String) extends IndexedView[Char] {
val start = 0
val end = s.length
def length = s.length
def apply(n: Int) = s.charAt(n)
override def className = "StringView"
}
Expand All @@ -732,11 +741,15 @@ object CollectionStrawMan6 extends LowPriority {
implicit class ArrayOps[A](val xs: Array[A])
extends AnyVal with IterableOps[A]
with SeqMonoTransforms[A, Array[A]]
with Buildable[A, Array[A]] {
with Buildable[A, Array[A]]
with ArrayLike[A] {

protected def coll = new ArrayView(xs)
def iterator = coll.iterator

def length = xs.length
def apply(i: Int) = xs.apply(i)

override def view = new ArrayView(xs)

def elemTag: ClassTag[A] = ClassTag(xs.getClass.getComponentType)
Expand All @@ -758,8 +771,7 @@ object CollectionStrawMan6 extends LowPriority {
}

case class ArrayView[A](xs: Array[A]) extends IndexedView[A] {
val start = 0
val end = xs.length
def length = xs.length
def apply(n: Int) = xs(n)
override def className = "ArrayView"
}
Expand Down Expand Up @@ -823,15 +835,17 @@ object CollectionStrawMan6 extends LowPriority {
/** A view that drops leading elements of the underlying collection. */
case class Drop[A](underlying: Iterable[A], n: Int) extends View[A] {
def iterator = underlying.iterator.drop(n)
protected val normN = n max 0
override def knownSize =
if (underlying.knownSize >= 0) underlying.knownSize - n max 0 else -1
if (underlying.knownSize >= 0) (underlying.knownSize - normN) max 0 else -1
}

/** A view that takes leading elements of the underlying collection. */
case class Take[A](underlying: Iterable[A], n: Int) extends View[A] {
def iterator = underlying.iterator.take(n)
protected val normN = n max 0
override def knownSize =
if (underlying.knownSize >= 0) underlying.knownSize min n else -1
if (underlying.knownSize >= 0) underlying.knownSize min normN else -1
}

/** A view that maps elements of the underlying collection. */
Expand Down Expand Up @@ -873,29 +887,51 @@ object CollectionStrawMan6 extends LowPriority {
}

/** View defined in terms of indexing a range */
trait IndexedView[+A] extends View[A] { self =>
def start: Int
def end: Int
def apply(i: Int): A
trait IndexedView[+A] extends View[A] with ArrayLike[A] {

def iterator: Iterator[A] = new Iterator[A] {
private var current = start
def hasNext = current < end
private var current = 0
def hasNext = current < length
def next: A = {
val r = apply(current)
current += 1
r
}
}

def reverse = new IndexedView[A] {
def start = self.start
def end = self.end
def apply(i: Int) = self.apply(end - 1 - i)
override def take(n: Int): IndexedView[A] = new IndexedView.Take(this, n)
override def drop(n: Int): IndexedView[A] = new IndexedView.Drop(this, n)
override def map[B](f: A => B): IndexedView[B] = new IndexedView.Map(this, f)
def reverse: IndexedView[A] = new IndexedView.Reverse(this)
}

object IndexedView {

class Take[A](underlying: IndexedView[A], n: Int)
extends View.Take(underlying, n) with IndexedView[A] {
override def iterator = super.iterator
def length = underlying.length min normN
def apply(i: Int) = underlying.apply(i)
}

def length = end - start max 0
override def knownSize = length
class Drop[A](underlying: IndexedView[A], n: Int)
extends View.Take(underlying, n) with IndexedView[A] {
override def iterator = super.iterator
def length = (underlying.length - normN) max 0
def apply(i: Int) = underlying.apply(i + normN)
}

class Map[A, B](underlying: IndexedView[A], f: A => B)
extends View.Map(underlying, f) with IndexedView[B] {
override def iterator = super.iterator
def length = underlying.length
def apply(n: Int) = f(underlying.apply(n))
}

case class Reverse[A](underlying: IndexedView[A]) extends IndexedView[A] {
def length = underlying.length
def apply(i: Int) = underlying.apply(length - 1 - i)
}
}

/* ---------- Iterators ---------------------------------------------------*/
Expand Down Expand Up @@ -1003,8 +1039,7 @@ object CollectionStrawMan6 extends LowPriority {
def next = throw new NoSuchElementException("next on empty iterator")
}
def apply[A](xs: A*): Iterator[A] = new IndexedView[A] {
val start = 0
val end = xs.length
val length = xs.length
def apply(n: Int) = xs(n)
}.iterator
}
Expand Down