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				| <!doctype html> | |
| 
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| <title>CodeMirror: Scala mode</title> | |
| <meta charset="utf-8"/> | |
| <link rel=stylesheet href="../../doc/docs.css"> | |
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|   <a href="http://codemirror.net"><h1>CodeMirror</h1><img id=logo src="../../doc/logo.png"></a> | |
| 
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|   <ul> | |
|     <li><a href="../../index.html">Home</a> | |
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| <h2>Scala mode</h2> | |
| <form> | |
| <textarea id="code" name="code"> | |
| 
 | |
|   /*                     __                                               *\ | |
|   **     ________ ___   / /  ___     Scala API                            ** | |
|   **    / __/ __// _ | / /  / _ |    (c) 2003-2011, LAMP/EPFL             ** | |
|   **  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               ** | |
|   ** /____/\___/_/ |_/____/_/ | |                                         ** | |
|   **                          |/                                          ** | |
|   \*                                                                      */ | |
| 
 | |
|   package scala.collection | |
| 
 | |
|   import generic._ | |
|   import mutable.{ Builder, ListBuffer } | |
|   import annotation.{tailrec, migration, bridge} | |
|   import annotation.unchecked.{ uncheckedVariance => uV } | |
|   import parallel.ParIterable | |
| 
 | |
|   /** A template trait for traversable collections of type `Traversable[A]`. | |
|    *   | |
|    *  $traversableInfo | |
|    *  @define mutability | |
|    *  @define traversableInfo | |
|    *  This is a base trait of all kinds of $mutability Scala collections. It | |
|    *  implements the behavior common to all collections, in terms of a method | |
|    *  `foreach` with signature: | |
|    * {{{ | |
|    *     def foreach[U](f: Elem => U): Unit | |
|    * }}} | |
|    *  Collection classes mixing in this trait provide a concrete  | |
|    *  `foreach` method which traverses all the | |
|    *  elements contained in the collection, applying a given function to each. | |
|    *  They also need to provide a method `newBuilder` | |
|    *  which creates a builder for collections of the same kind. | |
|    *   | |
|    *  A traversable class might or might not have two properties: strictness | |
|    *  and orderedness. Neither is represented as a type. | |
|    *   | |
|    *  The instances of a strict collection class have all their elements | |
|    *  computed before they can be used as values. By contrast, instances of | |
|    *  a non-strict collection class may defer computation of some of their | |
|    *  elements until after the instance is available as a value. | |
|    *  A typical example of a non-strict collection class is a | |
|    *  <a href="../immutable/Stream.html" target="ContentFrame"> | |
|    *  `scala.collection.immutable.Stream`</a>. | |
|    *  A more general class of examples are `TraversableViews`. | |
|    *   | |
|    *  If a collection is an instance of an ordered collection class, traversing | |
|    *  its elements with `foreach` will always visit elements in the | |
|    *  same order, even for different runs of the program. If the class is not | |
|    *  ordered, `foreach` can visit elements in different orders for | |
|    *  different runs (but it will keep the same order in the same run).' | |
|    *  | |
|    *  A typical example of a collection class which is not ordered is a | |
|    *  `HashMap` of objects. The traversal order for hash maps will | |
|    *  depend on the hash codes of its elements, and these hash codes might | |
|    *  differ from one run to the next. By contrast, a `LinkedHashMap` | |
|    *  is ordered because it's `foreach` method visits elements in the | |
|    *  order they were inserted into the `HashMap`. | |
|    * | |
|    *  @author Martin Odersky | |
|    *  @version 2.8 | |
|    *  @since   2.8 | |
|    *  @tparam A    the element type of the collection | |
|    *  @tparam Repr the type of the actual collection containing the elements. | |
|    * | |
|    *  @define Coll Traversable | |
|    *  @define coll traversable collection | |
|    */ | |
|   trait TraversableLike[+A, +Repr] extends HasNewBuilder[A, Repr]  | |
|                                       with FilterMonadic[A, Repr] | |
|                                       with TraversableOnce[A] | |
|                                       with GenTraversableLike[A, Repr] | |
|                                       with Parallelizable[A, ParIterable[A]] | |
|   { | |
|     self => | |
| 
 | |
|     import Traversable.breaks._ | |
| 
 | |
|     /** The type implementing this traversable */ | |
|     protected type Self = Repr | |
| 
 | |
|     /** The collection of type $coll underlying this `TraversableLike` object. | |
|      *  By default this is implemented as the `TraversableLike` object itself, | |
|      *  but this can be overridden. | |
|      */ | |
|     def repr: Repr = this.asInstanceOf[Repr] | |
| 
 | |
|     /** The underlying collection seen as an instance of `$Coll`. | |
|      *  By default this is implemented as the current collection object itself, | |
|      *  but this can be overridden. | |
|      */ | |
|     protected[this] def thisCollection: Traversable[A] = this.asInstanceOf[Traversable[A]] | |
| 
 | |
|     /** A conversion from collections of type `Repr` to `$Coll` objects. | |
|      *  By default this is implemented as just a cast, but this can be overridden. | |
|      */ | |
|     protected[this] def toCollection(repr: Repr): Traversable[A] = repr.asInstanceOf[Traversable[A]] | |
| 
 | |
|     /** Creates a new builder for this collection type. | |
|      */ | |
|     protected[this] def newBuilder: Builder[A, Repr] | |
| 
 | |
|     protected[this] def parCombiner = ParIterable.newCombiner[A] | |
| 
 | |
|     /** Applies a function `f` to all elements of this $coll. | |
|      *   | |
|      *    Note: this method underlies the implementation of most other bulk operations. | |
|      *    It's important to implement this method in an efficient way. | |
|      *   | |
|      * | |
|      *  @param  f   the function that is applied for its side-effect to every element. | |
|      *              The result of function `f` is discarded. | |
|      *               | |
|      *  @tparam  U  the type parameter describing the result of function `f`.  | |
|      *              This result will always be ignored. Typically `U` is `Unit`, | |
|      *              but this is not necessary. | |
|      * | |
|      *  @usecase def foreach(f: A => Unit): Unit | |
|      */ | |
|     def foreach[U](f: A => U): Unit | |
| 
 | |
|     /** Tests whether this $coll is empty. | |
|      * | |
|      *  @return    `true` if the $coll contain no elements, `false` otherwise. | |
|      */ | |
|     def isEmpty: Boolean = { | |
|       var result = true | |
|       breakable { | |
|         for (x <- this) { | |
|           result = false | |
|           break | |
|         } | |
|       } | |
|       result | |
|     } | |
| 
 | |
|     /** Tests whether this $coll is known to have a finite size. | |
|      *  All strict collections are known to have finite size. For a non-strict collection | |
|      *  such as `Stream`, the predicate returns `true` if all elements have been computed. | |
|      *  It returns `false` if the stream is not yet evaluated to the end. | |
|      * | |
|      *  Note: many collection methods will not work on collections of infinite sizes.  | |
|      * | |
|      *  @return  `true` if this collection is known to have finite size, `false` otherwise. | |
|      */ | |
|     def hasDefiniteSize = true | |
| 
 | |
|     def ++[B >: A, That](that: GenTraversableOnce[B])(implicit bf: CanBuildFrom[Repr, B, That]): That = { | |
|       val b = bf(repr) | |
|       if (that.isInstanceOf[IndexedSeqLike[_, _]]) b.sizeHint(this, that.seq.size) | |
|       b ++= thisCollection | |
|       b ++= that.seq | |
|       b.result | |
|     } | |
| 
 | |
|     @bridge | |
|     def ++[B >: A, That](that: TraversableOnce[B])(implicit bf: CanBuildFrom[Repr, B, That]): That = | |
|       ++(that: GenTraversableOnce[B])(bf) | |
| 
 | |
|     /** Concatenates this $coll with the elements of a traversable collection. | |
|      *  It differs from ++ in that the right operand determines the type of the | |
|      *  resulting collection rather than the left one. | |
|      *  | |
|      *  @param that   the traversable to append. | |
|      *  @tparam B     the element type of the returned collection.  | |
|      *  @tparam That  $thatinfo | |
|      *  @param bf     $bfinfo | |
|      *  @return       a new collection of type `That` which contains all elements | |
|      *                of this $coll followed by all elements of `that`. | |
|      *  | |
|      *  @usecase def ++:[B](that: TraversableOnce[B]): $Coll[B] | |
|      *   | |
|      *  @return       a new $coll which contains all elements of this $coll | |
|      *                followed by all elements of `that`. | |
|      */ | |
|     def ++:[B >: A, That](that: TraversableOnce[B])(implicit bf: CanBuildFrom[Repr, B, That]): That = { | |
|       val b = bf(repr) | |
|       if (that.isInstanceOf[IndexedSeqLike[_, _]]) b.sizeHint(this, that.size) | |
|       b ++= that | |
|       b ++= thisCollection | |
|       b.result | |
|     } | |
| 
 | |
|     /** This overload exists because: for the implementation of ++: we should reuse | |
|      *  that of ++ because many collections override it with more efficient versions. | |
|      *  Since TraversableOnce has no '++' method, we have to implement that directly, | |
|      *  but Traversable and down can use the overload. | |
|      */ | |
|     def ++:[B >: A, That](that: Traversable[B])(implicit bf: CanBuildFrom[Repr, B, That]): That = | |
|       (that ++ seq)(breakOut) | |
| 
 | |
|     def map[B, That](f: A => B)(implicit bf: CanBuildFrom[Repr, B, That]): That = { | |
|       val b = bf(repr) | |
|       b.sizeHint(this)  | |
|       for (x <- this) b += f(x) | |
|       b.result | |
|     } | |
| 
 | |
|     def flatMap[B, That](f: A => GenTraversableOnce[B])(implicit bf: CanBuildFrom[Repr, B, That]): That = { | |
|       val b = bf(repr) | |
|       for (x <- this) b ++= f(x).seq | |
|       b.result | |
|     } | |
| 
 | |
|     /** Selects all elements of this $coll which satisfy a predicate. | |
|      * | |
|      *  @param p     the predicate used to test elements. | |
|      *  @return      a new $coll consisting of all elements of this $coll that satisfy the given | |
|      *               predicate `p`. The order of the elements is preserved. | |
|      */ | |
|     def filter(p: A => Boolean): Repr = { | |
|       val b = newBuilder | |
|       for (x <- this)  | |
|         if (p(x)) b += x | |
|       b.result | |
|     } | |
| 
 | |
|     /** Selects all elements of this $coll which do not satisfy a predicate. | |
|      * | |
|      *  @param p     the predicate used to test elements. | |
|      *  @return      a new $coll consisting of all elements of this $coll that do not satisfy the given | |
|      *               predicate `p`. The order of the elements is preserved. | |
|      */ | |
|     def filterNot(p: A => Boolean): Repr = filter(!p(_)) | |
| 
 | |
|     def collect[B, That](pf: PartialFunction[A, B])(implicit bf: CanBuildFrom[Repr, B, That]): That = { | |
|       val b = bf(repr) | |
|       for (x <- this) if (pf.isDefinedAt(x)) b += pf(x) | |
|       b.result | |
|     } | |
| 
 | |
|     /** Builds a new collection by applying an option-valued function to all | |
|      *  elements of this $coll on which the function is defined. | |
|      * | |
|      *  @param f      the option-valued function which filters and maps the $coll. | |
|      *  @tparam B     the element type of the returned collection. | |
|      *  @tparam That  $thatinfo | |
|      *  @param bf     $bfinfo | |
|      *  @return       a new collection of type `That` resulting from applying the option-valued function | |
|      *                `f` to each element and collecting all defined results. | |
|      *                The order of the elements is preserved. | |
|      * | |
|      *  @usecase def filterMap[B](f: A => Option[B]): $Coll[B] | |
|      *   | |
|      *  @param pf     the partial function which filters and maps the $coll. | |
|      *  @return       a new $coll resulting from applying the given option-valued function | |
|      *                `f` to each element and collecting all defined results. | |
|      *                The order of the elements is preserved. | |
|     def filterMap[B, That](f: A => Option[B])(implicit bf: CanBuildFrom[Repr, B, That]): That = { | |
|       val b = bf(repr) | |
|       for (x <- this)  | |
|         f(x) match { | |
|           case Some(y) => b += y | |
|           case _ => | |
|         } | |
|       b.result | |
|     } | |
|      */ | |
| 
 | |
|     /** Partitions this $coll in two ${coll}s according to a predicate. | |
|      * | |
|      *  @param p the predicate on which to partition. | |
|      *  @return  a pair of ${coll}s: the first $coll consists of all elements that  | |
|      *           satisfy the predicate `p` and the second $coll consists of all elements | |
|      *           that don't. The relative order of the elements in the resulting ${coll}s | |
|      *           is the same as in the original $coll. | |
|      */ | |
|     def partition(p: A => Boolean): (Repr, Repr) = { | |
|       val l, r = newBuilder | |
|       for (x <- this) (if (p(x)) l else r) += x | |
|       (l.result, r.result) | |
|     } | |
| 
 | |
|     def groupBy[K](f: A => K): immutable.Map[K, Repr] = { | |
|       val m = mutable.Map.empty[K, Builder[A, Repr]] | |
|       for (elem <- this) { | |
|         val key = f(elem) | |
|         val bldr = m.getOrElseUpdate(key, newBuilder) | |
|         bldr += elem | |
|       } | |
|       val b = immutable.Map.newBuilder[K, Repr] | |
|       for ((k, v) <- m) | |
|         b += ((k, v.result)) | |
| 
 | |
|       b.result | |
|     } | |
| 
 | |
|     /** Tests whether a predicate holds for all elements of this $coll. | |
|      * | |
|      *  $mayNotTerminateInf | |
|      * | |
|      *  @param   p     the predicate used to test elements. | |
|      *  @return        `true` if the given predicate `p` holds for all elements | |
|      *                 of this $coll, otherwise `false`. | |
|      */ | |
|     def forall(p: A => Boolean): Boolean = { | |
|       var result = true | |
|       breakable { | |
|         for (x <- this) | |
|           if (!p(x)) { result = false; break } | |
|       } | |
|       result | |
|     } | |
| 
 | |
|     /** Tests whether a predicate holds for some of the elements of this $coll. | |
|      * | |
|      *  $mayNotTerminateInf | |
|      * | |
|      *  @param   p     the predicate used to test elements. | |
|      *  @return        `true` if the given predicate `p` holds for some of the | |
|      *                 elements of this $coll, otherwise `false`. | |
|      */ | |
|     def exists(p: A => Boolean): Boolean = { | |
|       var result = false | |
|       breakable { | |
|         for (x <- this) | |
|           if (p(x)) { result = true; break } | |
|       } | |
|       result | |
|     } | |
| 
 | |
|     /** Finds the first element of the $coll satisfying a predicate, if any. | |
|      *  | |
|      *  $mayNotTerminateInf | |
|      *  $orderDependent | |
|      * | |
|      *  @param p    the predicate used to test elements. | |
|      *  @return     an option value containing the first element in the $coll | |
|      *              that satisfies `p`, or `None` if none exists. | |
|      */ | |
|     def find(p: A => Boolean): Option[A] = { | |
|       var result: Option[A] = None | |
|       breakable { | |
|         for (x <- this) | |
|           if (p(x)) { result = Some(x); break } | |
|       } | |
|       result | |
|     } | |
| 
 | |
|     def scan[B >: A, That](z: B)(op: (B, B) => B)(implicit cbf: CanBuildFrom[Repr, B, That]): That = scanLeft(z)(op) | |
| 
 | |
|     def scanLeft[B, That](z: B)(op: (B, A) => B)(implicit bf: CanBuildFrom[Repr, B, That]): That = { | |
|       val b = bf(repr) | |
|       b.sizeHint(this, 1) | |
|       var acc = z | |
|       b += acc | |
|       for (x <- this) { acc = op(acc, x); b += acc } | |
|       b.result | |
|     } | |
| 
 | |
|     @migration(2, 9, | |
|       "This scanRight definition has changed in 2.9.\n" + | |
|       "The previous behavior can be reproduced with scanRight.reverse." | |
|     ) | |
|     def scanRight[B, That](z: B)(op: (A, B) => B)(implicit bf: CanBuildFrom[Repr, B, That]): That = { | |
|       var scanned = List(z) | |
|       var acc = z | |
|       for (x <- reversed) { | |
|         acc = op(x, acc) | |
|         scanned ::= acc | |
|       } | |
|       val b = bf(repr) | |
|       for (elem <- scanned) b += elem | |
|       b.result | |
|     } | |
| 
 | |
|     /** Selects the first element of this $coll. | |
|      *  $orderDependent | |
|      *  @return  the first element of this $coll. | |
|      *  @throws `NoSuchElementException` if the $coll is empty. | |
|      */ | |
|     def head: A = { | |
|       var result: () => A = () => throw new NoSuchElementException | |
|       breakable { | |
|         for (x <- this) { | |
|           result = () => x | |
|           break | |
|         } | |
|       } | |
|       result() | |
|     } | |
| 
 | |
|     /** Optionally selects the first element. | |
|      *  $orderDependent | |
|      *  @return  the first element of this $coll if it is nonempty, `None` if it is empty. | |
|      */ | |
|     def headOption: Option[A] = if (isEmpty) None else Some(head) | |
| 
 | |
|     /** Selects all elements except the first. | |
|      *  $orderDependent | |
|      *  @return  a $coll consisting of all elements of this $coll | |
|      *           except the first one. | |
|      *  @throws `UnsupportedOperationException` if the $coll is empty. | |
|      */  | |
|     override def tail: Repr = { | |
|       if (isEmpty) throw new UnsupportedOperationException("empty.tail") | |
|       drop(1) | |
|     } | |
| 
 | |
|     /** Selects the last element. | |
|       * $orderDependent | |
|       * @return The last element of this $coll. | |
|       * @throws NoSuchElementException If the $coll is empty. | |
|       */ | |
|     def last: A = { | |
|       var lst = head | |
|       for (x <- this) | |
|         lst = x | |
|       lst | |
|     } | |
| 
 | |
|     /** Optionally selects the last element. | |
|      *  $orderDependent | |
|      *  @return  the last element of this $coll$ if it is nonempty, `None` if it is empty. | |
|      */ | |
|     def lastOption: Option[A] = if (isEmpty) None else Some(last) | |
| 
 | |
|     /** Selects all elements except the last. | |
|      *  $orderDependent | |
|      *  @return  a $coll consisting of all elements of this $coll | |
|      *           except the last one. | |
|      *  @throws `UnsupportedOperationException` if the $coll is empty. | |
|      */ | |
|     def init: Repr = { | |
|       if (isEmpty) throw new UnsupportedOperationException("empty.init") | |
|       var lst = head | |
|       var follow = false | |
|       val b = newBuilder | |
|       b.sizeHint(this, -1) | |
|       for (x <- this.seq) { | |
|         if (follow) b += lst | |
|         else follow = true | |
|         lst = x | |
|       } | |
|       b.result | |
|     } | |
| 
 | |
|     def take(n: Int): Repr = slice(0, n) | |
| 
 | |
|     def drop(n: Int): Repr =  | |
|       if (n <= 0) { | |
|         val b = newBuilder | |
|         b.sizeHint(this) | |
|         b ++= thisCollection result | |
|       } | |
|       else sliceWithKnownDelta(n, Int.MaxValue, -n) | |
| 
 | |
|     def slice(from: Int, until: Int): Repr = sliceWithKnownBound(math.max(from, 0), until) | |
| 
 | |
|     // Precondition: from >= 0, until > 0, builder already configured for building. | |
|     private[this] def sliceInternal(from: Int, until: Int, b: Builder[A, Repr]): Repr = { | |
|       var i = 0 | |
|       breakable { | |
|         for (x <- this.seq) { | |
|           if (i >= from) b += x | |
|           i += 1 | |
|           if (i >= until) break | |
|         } | |
|       } | |
|       b.result | |
|     } | |
|     // Precondition: from >= 0 | |
|     private[scala] def sliceWithKnownDelta(from: Int, until: Int, delta: Int): Repr = { | |
|       val b = newBuilder | |
|       if (until <= from) b.result | |
|       else { | |
|         b.sizeHint(this, delta) | |
|         sliceInternal(from, until, b) | |
|       } | |
|     } | |
|     // Precondition: from >= 0 | |
|     private[scala] def sliceWithKnownBound(from: Int, until: Int): Repr = { | |
|       val b = newBuilder | |
|       if (until <= from) b.result | |
|       else { | |
|         b.sizeHintBounded(until - from, this)       | |
|         sliceInternal(from, until, b) | |
|       } | |
|     } | |
| 
 | |
|     def takeWhile(p: A => Boolean): Repr = { | |
|       val b = newBuilder | |
|       breakable { | |
|         for (x <- this) { | |
|           if (!p(x)) break | |
|           b += x | |
|         } | |
|       } | |
|       b.result | |
|     } | |
| 
 | |
|     def dropWhile(p: A => Boolean): Repr = { | |
|       val b = newBuilder | |
|       var go = false | |
|       for (x <- this) { | |
|         if (!p(x)) go = true | |
|         if (go) b += x | |
|       } | |
|       b.result | |
|     } | |
| 
 | |
|     def span(p: A => Boolean): (Repr, Repr) = { | |
|       val l, r = newBuilder | |
|       var toLeft = true | |
|       for (x <- this) { | |
|         toLeft = toLeft && p(x) | |
|         (if (toLeft) l else r) += x | |
|       } | |
|       (l.result, r.result) | |
|     } | |
| 
 | |
|     def splitAt(n: Int): (Repr, Repr) = { | |
|       val l, r = newBuilder | |
|       l.sizeHintBounded(n, this) | |
|       if (n >= 0) r.sizeHint(this, -n) | |
|       var i = 0 | |
|       for (x <- this) { | |
|         (if (i < n) l else r) += x | |
|         i += 1 | |
|       } | |
|       (l.result, r.result) | |
|     } | |
| 
 | |
|     /** Iterates over the tails of this $coll. The first value will be this | |
|      *  $coll and the final one will be an empty $coll, with the intervening | |
|      *  values the results of successive applications of `tail`. | |
|      * | |
|      *  @return   an iterator over all the tails of this $coll | |
|      *  @example  `List(1,2,3).tails = Iterator(List(1,2,3), List(2,3), List(3), Nil)` | |
|      */   | |
|     def tails: Iterator[Repr] = iterateUntilEmpty(_.tail) | |
| 
 | |
|     /** Iterates over the inits of this $coll. The first value will be this | |
|      *  $coll and the final one will be an empty $coll, with the intervening | |
|      *  values the results of successive applications of `init`. | |
|      * | |
|      *  @return  an iterator over all the inits of this $coll | |
|      *  @example  `List(1,2,3).inits = Iterator(List(1,2,3), List(1,2), List(1), Nil)` | |
|      */ | |
|     def inits: Iterator[Repr] = iterateUntilEmpty(_.init) | |
| 
 | |
|     /** Copies elements of this $coll to an array. | |
|      *  Fills the given array `xs` with at most `len` elements of | |
|      *  this $coll, starting at position `start`. | |
|      *  Copying will stop once either the end of the current $coll is reached, | |
|      *  or the end of the array is reached, or `len` elements have been copied. | |
|      * | |
|      *  $willNotTerminateInf | |
|      *  | |
|      *  @param  xs     the array to fill. | |
|      *  @param  start  the starting index. | |
|      *  @param  len    the maximal number of elements to copy. | |
|      *  @tparam B      the type of the elements of the array.  | |
|      *  | |
|      * | |
|      *  @usecase def copyToArray(xs: Array[A], start: Int, len: Int): Unit | |
|      */ | |
|     def copyToArray[B >: A](xs: Array[B], start: Int, len: Int) { | |
|       var i = start | |
|       val end = (start + len) min xs.length | |
|       breakable { | |
|         for (x <- this) { | |
|           if (i >= end) break | |
|           xs(i) = x | |
|           i += 1 | |
|         } | |
|       } | |
|     } | |
| 
 | |
|     def toTraversable: Traversable[A] = thisCollection | |
|     def toIterator: Iterator[A] = toStream.iterator | |
|     def toStream: Stream[A] = toBuffer.toStream | |
| 
 | |
|     /** Converts this $coll to a string. | |
|      * | |
|      *  @return   a string representation of this collection. By default this | |
|      *            string consists of the `stringPrefix` of this $coll, | |
|      *            followed by all elements separated by commas and enclosed in parentheses. | |
|      */ | |
|     override def toString = mkString(stringPrefix + "(", ", ", ")") | |
| 
 | |
|     /** Defines the prefix of this object's `toString` representation. | |
|      * | |
|      *  @return  a string representation which starts the result of `toString` | |
|      *           applied to this $coll. By default the string prefix is the | |
|      *           simple name of the collection class $coll. | |
|      */ | |
|     def stringPrefix : String = { | |
|       var string = repr.asInstanceOf[AnyRef].getClass.getName | |
|       val idx1 = string.lastIndexOf('.' : Int) | |
|       if (idx1 != -1) string = string.substring(idx1 + 1) | |
|       val idx2 = string.indexOf('$') | |
|       if (idx2 != -1) string = string.substring(0, idx2) | |
|       string | |
|     } | |
| 
 | |
|     /** Creates a non-strict view of this $coll. | |
|      *  | |
|      *  @return a non-strict view of this $coll. | |
|      */ | |
|     def view = new TraversableView[A, Repr] { | |
|       protected lazy val underlying = self.repr | |
|       override def foreach[U](f: A => U) = self foreach f | |
|     } | |
| 
 | |
|     /** Creates a non-strict view of a slice of this $coll. | |
|      * | |
|      *  Note: the difference between `view` and `slice` is that `view` produces | |
|      *        a view of the current $coll, whereas `slice` produces a new $coll. | |
|      *  | |
|      *  Note: `view(from, to)` is equivalent to `view.slice(from, to)` | |
|      *  $orderDependent | |
|      *  | |
|      *  @param from   the index of the first element of the view | |
|      *  @param until  the index of the element following the view | |
|      *  @return a non-strict view of a slice of this $coll, starting at index `from` | |
|      *  and extending up to (but not including) index `until`. | |
|      */ | |
|     def view(from: Int, until: Int): TraversableView[A, Repr] = view.slice(from, until) | |
| 
 | |
|     /** Creates a non-strict filter of this $coll. | |
|      * | |
|      *  Note: the difference between `c filter p` and `c withFilter p` is that | |
|      *        the former creates a new collection, whereas the latter only | |
|      *        restricts the domain of subsequent `map`, `flatMap`, `foreach`, | |
|      *        and `withFilter` operations. | |
|      *  $orderDependent | |
|      *  | |
|      *  @param p   the predicate used to test elements. | |
|      *  @return    an object of class `WithFilter`, which supports | |
|      *             `map`, `flatMap`, `foreach`, and `withFilter` operations. | |
|      *             All these operations apply to those elements of this $coll which | |
|      *             satisfy the predicate `p`. | |
|      */ | |
|     def withFilter(p: A => Boolean): FilterMonadic[A, Repr] = new WithFilter(p) | |
| 
 | |
|     /** A class supporting filtered operations. Instances of this class are | |
|      *  returned by method `withFilter`. | |
|      */ | |
|     class WithFilter(p: A => Boolean) extends FilterMonadic[A, Repr] { | |
| 
 | |
|       /** Builds a new collection by applying a function to all elements of the | |
|        *  outer $coll containing this `WithFilter` instance that satisfy predicate `p`. | |
|        * | |
|        *  @param f      the function to apply to each element. | |
|        *  @tparam B     the element type of the returned collection. | |
|        *  @tparam That  $thatinfo | |
|        *  @param bf     $bfinfo | |
|        *  @return       a new collection of type `That` resulting from applying | |
|        *                the given function `f` to each element of the outer $coll | |
|        *                that satisfies predicate `p` and collecting the results. | |
|        * | |
|        *  @usecase def map[B](f: A => B): $Coll[B]  | |
|        *   | |
|        *  @return       a new $coll resulting from applying the given function | |
|        *                `f` to each element of the outer $coll that satisfies | |
|        *                predicate `p` and collecting the results. | |
|        */ | |
|       def map[B, That](f: A => B)(implicit bf: CanBuildFrom[Repr, B, That]): That = { | |
|         val b = bf(repr) | |
|         for (x <- self)  | |
|           if (p(x)) b += f(x) | |
|         b.result | |
|       } | |
| 
 | |
|       /** Builds a new collection by applying a function to all elements of the | |
|        *  outer $coll containing this `WithFilter` instance that satisfy | |
|        *  predicate `p` and concatenating the results.  | |
|        * | |
|        *  @param f      the function to apply to each element. | |
|        *  @tparam B     the element type of the returned collection. | |
|        *  @tparam That  $thatinfo | |
|        *  @param bf     $bfinfo | |
|        *  @return       a new collection of type `That` resulting from applying | |
|        *                the given collection-valued function `f` to each element | |
|        *                of the outer $coll that satisfies predicate `p` and | |
|        *                concatenating the results. | |
|        * | |
|        *  @usecase def flatMap[B](f: A => TraversableOnce[B]): $Coll[B] | |
|        *  | |
|        *  @return       a new $coll resulting from applying the given collection-valued function | |
|        *                `f` to each element of the outer $coll that satisfies predicate `p` and concatenating the results. | |
|        */ | |
|       def flatMap[B, That](f: A => GenTraversableOnce[B])(implicit bf: CanBuildFrom[Repr, B, That]): That = { | |
|         val b = bf(repr) | |
|         for (x <- self)  | |
|           if (p(x)) b ++= f(x).seq | |
|         b.result | |
|       } | |
| 
 | |
|       /** Applies a function `f` to all elements of the outer $coll containing | |
|        *  this `WithFilter` instance that satisfy predicate `p`. | |
|        * | |
|        *  @param  f   the function that is applied for its side-effect to every element. | |
|        *              The result of function `f` is discarded. | |
|        *               | |
|        *  @tparam  U  the type parameter describing the result of function `f`.  | |
|        *              This result will always be ignored. Typically `U` is `Unit`, | |
|        *              but this is not necessary. | |
|        * | |
|        *  @usecase def foreach(f: A => Unit): Unit | |
|        */    | |
|       def foreach[U](f: A => U): Unit =  | |
|         for (x <- self)  | |
|           if (p(x)) f(x) | |
| 
 | |
|       /** Further refines the filter for this $coll. | |
|        * | |
|        *  @param q   the predicate used to test elements. | |
|        *  @return    an object of class `WithFilter`, which supports | |
|        *             `map`, `flatMap`, `foreach`, and `withFilter` operations. | |
|        *             All these operations apply to those elements of this $coll which | |
|        *             satisfy the predicate `q` in addition to the predicate `p`. | |
|        */ | |
|       def withFilter(q: A => Boolean): WithFilter =  | |
|         new WithFilter(x => p(x) && q(x)) | |
|     } | |
| 
 | |
|     // A helper for tails and inits. | |
|     private def iterateUntilEmpty(f: Traversable[A @uV] => Traversable[A @uV]): Iterator[Repr] = { | |
|       val it = Iterator.iterate(thisCollection)(f) takeWhile (x => !x.isEmpty) | |
|       it ++ Iterator(Nil) map (newBuilder ++= _ result) | |
|     } | |
|   } | |
| 
 | |
| 
 | |
| </textarea> | |
| </form> | |
| 
 | |
|     <script> | |
|       var editor = CodeMirror.fromTextArea(document.getElementById("code"), { | |
|         lineNumbers: true, | |
|         matchBrackets: true, | |
|         theme: "ambiance", | |
|         mode: "text/x-scala" | |
|       }); | |
|     </script> | |
|   </article>
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