mirror of
https://github.com/renbaoshuo/S2OJ.git
synced 2024-11-06 03:28:42 +00:00
96d4a3ecf7
Due to historical reasons, the code is in subfolder "1". With SVN removal, we place the code back and remove the annoying "1" folder.
768 lines
28 KiB
HTML
768 lines
28 KiB
HTML
<!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="http://codemirror.net"><img id=logo src="../../doc/logo.png"></a>
|
|
|
|
<ul>
|
|
<li><a href="../../index.html">Home</a>
|
|
<li><a href="../../doc/manual.html">Manual</a>
|
|
<li><a href="https://github.com/marijnh/codemirror">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>
|