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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/.cms/lib/codemirror/mode/clike/scala.html Fri Oct 11 22:40:23 2024 +0000 @@ -0,0 +1,767 @@ +<!doctype html> + +<title>CodeMirror: Scala mode</title> +<meta charset="utf-8"/> +<link rel=stylesheet href="../../doc/docs.css"> + +<link rel="stylesheet" href="../../lib/codemirror.css"> +<link rel="stylesheet" href="../../theme/ambiance.css"> +<script src="../../lib/codemirror.js"></script> +<script src="../../addon/edit/matchbrackets.js"></script> +<script src="clike.js"></script> +<div id=nav> + <a href="https://codemirror.net/5"><h1>CodeMirror</h1><img id=logo src="../../doc/logo.png" alt=""></a> + + <ul> + <li><a href="../../index.html">Home</a> + <li><a href="../../doc/manual.html">Manual</a> + <li><a href="https://github.com/codemirror/codemirror5">Code</a> + </ul> + <ul> + <li><a href="../index.html">Language modes</a> + <li><a class=active href="#">Scala</a> + </ul> +</div> + +<article> +<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>