Add LongMap + friends to stdlib

Author: odersky

tests/pos-special/stdlib/collection/mutable/ImmutableBuilder.scala

@@ -0,0 +1,32 @@
+/*
+ * Scala (https://www.scala-lang.org)
+ *
+ * Copyright EPFL and Lightbend, Inc.
+ *
+ * Licensed under Apache License 2.0
+ * (http://www.apache.org/licenses/LICENSE-2.0).
+ *
+ * See the NOTICE file distributed with this work for
+ * additional information regarding copyright ownership.
+ */
+
+package scala
+package collection
+package mutable
+import language.experimental.captureChecking
+
+
+/**
+  * Reusable builder for immutable collections
+  */
+abstract class ImmutableBuilder[-A, C <: IterableOnce[_]](empty: C)
+  extends ReusableBuilder[A, C] {
+
+  protected var elems: C = empty
+
+  def clear(): Unit = { elems = empty }
+
+  def result(): C = elems
+
+  override def knownSize: Int = elems.knownSize
+}

tests/pos-special/stdlib/collection/mutable/ListMap.scala

@@ -0,0 +1,83 @@
+/*
+ * Scala (https://www.scala-lang.org)
+ *
+ * Copyright EPFL and Lightbend, Inc.
+ *
+ * Licensed under Apache License 2.0
+ * (http://www.apache.org/licenses/LICENSE-2.0).
+ *
+ * See the NOTICE file distributed with this work for
+ * additional information regarding copyright ownership.
+ */
+
+package scala.collection
+package mutable
+
+import scala.annotation.tailrec
+import scala.collection.generic.DefaultSerializable
+import scala.collection.immutable.List
+import language.experimental.captureChecking
+
+/** A simple mutable map backed by a list, so it preserves insertion order.
+  *
+  *  @tparam K    the type of the keys contained in this list map.
+  *  @tparam V    the type of the values assigned to keys in this list map.
+  *
+  *  @define Coll `mutable.ListMap`
+  *  @define coll mutable list map
+  *  @define mayNotTerminateInf
+  *  @define willNotTerminateInf
+  *  @define orderDependent
+  *  @define orderDependentFold
+  */
+@deprecated("Use an immutable.ListMap assigned to a var instead of mutable.ListMap", "2.13.0")
+class ListMap[sealed K, sealed V]
+  extends AbstractMap[K, V]
+    with MapOps[K, V, ListMap, ListMap[K, V]]
+    with StrictOptimizedIterableOps[(K, V), Iterable, ListMap[K, V]]
+    with StrictOptimizedMapOps[K, V, ListMap, ListMap[K, V]]
+    with MapFactoryDefaults[K, V, ListMap, Iterable]
+    with DefaultSerializable {
+
+  override def mapFactory: MapFactory[ListMap] = ListMap
+
+  private[this] var elems: List[(K, V)] = List()
+  private[this] var siz: Int = 0
+
+  def get(key: K): Option[V] = elems find (_._1 == key) map (_._2)
+  def iterator: Iterator[(K, V)] = elems.iterator
+
+  final override def addOne(kv: (K, V)) = {
+    val (e, key0) = remove(kv._1, elems, List())
+    elems = (key0, kv._2) :: e
+    siz += 1; this
+  }
+
+  final override def subtractOne(key: K) = { elems = remove(key, elems, List())._1; this }
+
+  @tailrec
+  private def remove(key: K, elems: List[(K, V)], acc: List[(K, V)]): (List[(K, V)], K) = {
+    if (elems.isEmpty) (acc, key)
+    else if (elems.head._1 == key) { siz -= 1; (acc ::: elems.tail, elems.head._1) }
+    else remove(key, elems.tail, elems.head :: acc)
+  }
+
+  final override def clear(): Unit = { elems = List(); siz = 0 }
+
+  final override def size: Int = siz
+  override def knownSize: Int = size
+  override def isEmpty: Boolean = size == 0
+  override protected[this] def stringPrefix = "ListMap"
+}
+
+/** $factoryInfo
+  *  @define Coll `mutable.ListMap`
+  *  @define coll mutable list map
+  */
+@SerialVersionUID(3L)
+@deprecated("Use an immutable.ListMap assigned to a var instead of mutable.ListMap", "2.13.0")
+object ListMap extends MapFactory[ListMap] {
+  def empty[sealed K, sealed V]: ListMap[K, V] = new ListMap[K, V]
+  def from[sealed K, sealed V](it: IterableOnce[(K, V)]^): ListMap[K,V] = Growable.from(empty[K, V], it)
+  def newBuilder[sealed K, sealed V]: Builder[(K, V), ListMap[K,V]] = new GrowableBuilder(empty[K, V])
+}