documentation for scala.Array.

1 files changed, 94 insertions, 66 deletions

diff --git a/src/library/scala/Array.scala b/src/library/scala/Array.scala
index 250fd09602..e7ee280cef 100644
--- a/src/library/scala/Array.scala
+++ b/src/library/scala/Array.scala
@@ -16,7 +16,7 @@ import compat.Platform.arraycopy
 import scala.reflect.ClassManifest
 import scala.runtime.ScalaRunTime.{array_apply, array_update}
 
-/** A class containing a fall back builder for arrays where the element type
+/** Contains a fallback builder for arrays when the element type
  *  does not have a class manifest. In that case a generic array is built.
  */
 class FallbackArrayBuilding {
@@ -35,7 +35,7 @@ class FallbackArrayBuilding {
     }
 }
 
-/** This object contains utility methods operating on arrays.
+/** Utility methods for operating on arrays.
  *
  *  @author Martin Odersky
  *  @version 1.0
@@ -47,6 +47,9 @@ object Array extends FallbackArrayBuilding {
       def apply() = ArrayBuilder.make[T]()(m)
     }
 
+  /**
+   * Returns a new [[scala.collection.mutable.ArrayBuilder]].
+   */
   def newBuilder[T](implicit m: ClassManifest[T]): ArrayBuilder[T] = ArrayBuilder.make[T]()(m)
 
   private def slowcopy(src : AnyRef,
@@ -65,15 +68,19 @@ object Array extends FallbackArrayBuilding {
   }
 
   /** Copy one array to another.
-   *  Equivalent to
-   *    <code>System.arraycopy(src, srcPos, dest, destPos, length)</code>,
-   *  except that this works also for polymorphic and boxed arrays.
+   *  Equivalent to Java's
+   *    `System.arraycopy(src, srcPos, dest, destPos, length)`,
+   *  except that this also works for polymorphic and boxed arrays.
+   *
+   *  Note that the passed-in `dest` array will be modified by this call.
    *
-   *  @param src     ...
-   *  @param srcPos  ...
-   *  @param dest    ...
-   *  @param destPos ...
-   *  @param length  ...
+   *  @param src the source array.
+   *  @param srcPos  starting position in the source array.
+   *  @param dest destination array.
+   *  @param destPos starting position in the destination array.
+   *  @param length the number of array elements to be copied.
+   *
+   *  @see `java.lang.System#arraycopy`
    */
   def copy(src: AnyRef, srcPos: Int, dest: AnyRef, destPos: Int, length: Int) {
     val srcClass = src.getClass
@@ -83,13 +90,13 @@ object Array extends FallbackArrayBuilding {
       slowcopy(src, srcPos, dest, destPos, length)
   }
 
-  /** Returns array of length 0 */
+  /** Returns an array of length 0 */
   def empty[T: ClassManifest]: Array[T] = new Array[T](0)
 
-  /** Create an array with given elements.
+  /** Creates an array with given elements.
    *
    *  @param xs the elements to put in the array
-   *  @return the array containing elements xs.
+   *  @return an array containing all elements from xs.
    */
   def apply[T: ClassManifest](xs: T*): Array[T] = {
     val array = new Array[T](xs.length)
@@ -98,6 +105,7 @@ object Array extends FallbackArrayBuilding {
     array
   }
 
+  /** Creates an array of `Boolean` objects */
   def apply(x: Boolean, xs: Boolean*): Array[Boolean] = {
     val array = new Array[Boolean](xs.length + 1)
     array(0) = x
@@ -106,6 +114,7 @@ object Array extends FallbackArrayBuilding {
     array
   }
 
+  /** Creates an array of `Byte` objects */
   def apply(x: Byte, xs: Byte*): Array[Byte] = {
     val array = new Array[Byte](xs.length + 1)
     array(0) = x
@@ -114,6 +123,7 @@ object Array extends FallbackArrayBuilding {
     array
   }
 
+  /** Creates an array of `Short` objects */
   def apply(x: Short, xs: Short*): Array[Short] = {
     val array = new Array[Short](xs.length + 1)
     array(0) = x
@@ -122,6 +132,7 @@ object Array extends FallbackArrayBuilding {
     array
   }
 
+  /** Creates an array of `Char` objects */
   def apply(x: Char, xs: Char*): Array[Char] = {
     val array = new Array[Char](xs.length + 1)
     array(0) = x
@@ -130,6 +141,7 @@ object Array extends FallbackArrayBuilding {
     array
   }
 
+  /** Creates an array of `Int` objects */
   def apply(x: Int, xs: Int*): Array[Int] = {
     val array = new Array[Int](xs.length + 1)
     array(0) = x
@@ -138,6 +150,7 @@ object Array extends FallbackArrayBuilding {
     array
   }
 
+  /** Creates an array of `Long` objects */
   def apply(x: Long, xs: Long*): Array[Long] = {
     val array = new Array[Long](xs.length + 1)
     array(0) = x
@@ -146,6 +159,7 @@ object Array extends FallbackArrayBuilding {
     array
   }
 
+  /** Creates an array of `Float` objects */
   def apply(x: Float, xs: Float*): Array[Float] = {
     val array = new Array[Float](xs.length + 1)
     array(0) = x
@@ -154,6 +168,7 @@ object Array extends FallbackArrayBuilding {
     array
   }
 
+  /** Creates an array of `Double` objects */
   def apply(x: Double, xs: Double*): Array[Double] = {
     val array = new Array[Double](xs.length + 1)
     array(0) = x
@@ -162,6 +177,7 @@ object Array extends FallbackArrayBuilding {
     array
   }
 
+  /** Creates an array of `Unit` objects */
   def apply(x: Unit, xs: Unit*): Array[Unit] = {
     val array = new Array[Unit](xs.length + 1)
     array(0) = x
@@ -170,26 +186,30 @@ object Array extends FallbackArrayBuilding {
     array
   }
 
-  /** Create array with given dimensions */
+  /** Creates array with given dimensions */
   def ofDim[T: ClassManifest](n1: Int): Array[T] =
     new Array[T](n1)
+  /** Creates a 2-dimensional array */
   def ofDim[T: ClassManifest](n1: Int, n2: Int): Array[Array[T]] = {
     val arr: Array[Array[T]] = (new Array[Array[T]](n1): Array[Array[T]])
     for (i <- 0 until n1) arr(i) = new Array[T](n2)
     arr
     // tabulate(n1)(_ => ofDim[T](n2))
   }
+  /** Creates a 3-dimensional array */
   def ofDim[T: ClassManifest](n1: Int, n2: Int, n3: Int): Array[Array[Array[T]]] =
     tabulate(n1)(_ => ofDim[T](n2, n3))
+  /** Creates a 4-dimensional array */
   def ofDim[T: ClassManifest](n1: Int, n2: Int, n3: Int, n4: Int): Array[Array[Array[Array[T]]]] =
     tabulate(n1)(_ => ofDim[T](n2, n3, n4))
+  /** Creates a 5-dimensional array */
   def ofDim[T: ClassManifest](n1: Int, n2: Int, n3: Int, n4: Int, n5: Int): Array[Array[Array[Array[Array[T]]]]] =
     tabulate(n1)(_ => ofDim[T](n2, n3, n4, n5))
 
-  /** Concatenate all argument sequences into a single array.
+  /** Concatenates all arrays into a single array.
    *
-   *  @param xs the given argument sequences
-   *  @return   the array created from the concatenated arguments
+   *  @param xss the given arrays
+   *  @return   the array created from concatenating `xss`
    */
   def concat[T: ClassManifest](xss: Array[T]*): Array[T] = {
     val b = newBuilder[T]
@@ -198,11 +218,19 @@ object Array extends FallbackArrayBuilding {
     b.result
   }
 
-  /** An array that contains the results of some element computation a number
+  /** Returns an array that contains the results of some element computation a number
    *  of times.
    *
-   *  @param   n  the number of elements returned
+   *  Note that this means that `elem` is computed a total of n times:
+   *  {{{
+   * scala> Array.fill(3){ java.lang.Math.random }
+   * res3: Array[Double] = Array(0.365461167592537, 1.550395944913685E-4, 0.7907242137333306)
+   *  }}}
+   *
+   *  @param   n  the number of elements desired
    *  @param   elem the element computation
+   *  @return an Array of size n, where each element contains the result of computing
+   *  `elem`.
    */
   def fill[T: ClassManifest](n: Int)(elem: => T): Array[T] = {
     val b = newBuilder[T]
@@ -215,7 +243,7 @@ object Array extends FallbackArrayBuilding {
     b.result
   }
 
-  /** A two-dimensional array that contains the results of some element
+  /** Returns a two-dimensional array that contains the results of some element
    *  computation a number of times.
    *
    *  @param   n1  the number of elements in the 1st dimension
@@ -225,7 +253,7 @@ object Array extends FallbackArrayBuilding {
   def fill[T: ClassManifest](n1: Int, n2: Int)(elem: => T): Array[Array[T]] =
     tabulate(n1)(_ => fill(n2)(elem))
 
-  /** A three-dimensional array that contains the results of some element
+  /** Returns a three-dimensional array that contains the results of some element
    *  computation a number of times.
    *
    *  @param   n1  the number of elements in the 1st dimension
@@ -236,7 +264,7 @@ object Array extends FallbackArrayBuilding {
   def fill[T: ClassManifest](n1: Int, n2: Int, n3: Int)(elem: => T): Array[Array[Array[T]]] =
     tabulate(n1)(_ => fill(n2, n3)(elem))
 
-  /** A four-dimensional array that contains the results of some element
+  /** Returns a four-dimensional array that contains the results of some element
    *  computation a number of times.
    *
    *  @param   n1  the number of elements in the 1st dimension
@@ -248,7 +276,7 @@ object Array extends FallbackArrayBuilding {
   def fill[T: ClassManifest](n1: Int, n2: Int, n3: Int, n4: Int)(elem: => T): Array[Array[Array[Array[T]]]] =
     tabulate(n1)(_ => fill(n2, n3, n4)(elem))
 
-  /** A five-dimensional array that contains the results of some element
+  /** Returns a five-dimensional array that contains the results of some element
    *  computation a number of times.
    *
    *  @param   n1  the number of elements in the 1st dimension
@@ -261,12 +289,12 @@ object Array extends FallbackArrayBuilding {
   def fill[T: ClassManifest](n1: Int, n2: Int, n3: Int, n4: Int, n5: Int)(elem: => T): Array[Array[Array[Array[Array[T]]]]] =
     tabulate(n1)(_ => fill(n2, n3, n4, n5)(elem))
 
-  /** An array containing values of a given function over a range of integer
+  /** Returns an array containing values of a given function over a range of integer
    *  values starting from 0.
    *
-   *  @param  n   The number of elements in the traversable
+   *  @param  n   The number of elements in the array
    *  @param  f   The function computing element values
-   *  @return A traversable consisting of elements `f(0), ..., f(n -1)`
+   *  @return A traversable consisting of elements `f(0),f(1), ..., f(n - 1)`
    */
   def tabulate[T: ClassManifest](n: Int)(f: Int => T): Array[T] = {
     val b = newBuilder[T]
@@ -279,7 +307,7 @@ object Array extends FallbackArrayBuilding {
     b.result
   }
 
-  /** A two-dimensional array containing values of a given function over
+  /** Returns a two-dimensional array containing values of a given function over
    *  ranges of integer values starting from 0.
    *
    *  @param   n1  the number of elements in the 1st dimension
@@ -289,7 +317,7 @@ object Array extends FallbackArrayBuilding {
   def tabulate[T: ClassManifest](n1: Int, n2: Int)(f: (Int, Int) => T): Array[Array[T]] =
     tabulate(n1)(i1 => tabulate(n2)(f(i1, _)))
 
-  /** A three-dimensional array containing values of a given function over
+  /** Returns a three-dimensional array containing values of a given function over
    *  ranges of integer values starting from 0.
    *
    *  @param   n1  the number of elements in the 1st dimension
@@ -300,7 +328,7 @@ object Array extends FallbackArrayBuilding {
   def tabulate[T: ClassManifest](n1: Int, n2: Int, n3: Int)(f: (Int, Int, Int) => T): Array[Array[Array[T]]] =
     tabulate(n1)(i1 => tabulate(n2, n3)(f(i1, _, _)))
 
-  /** A four-dimensional array containing values of a given function over
+  /** Returns a four-dimensional array containing values of a given function over
    *  ranges of integer values starting from 0.
    *
    *  @param   n1  the number of elements in the 1st dimension
@@ -312,7 +340,7 @@ object Array extends FallbackArrayBuilding {
   def tabulate[T: ClassManifest](n1: Int, n2: Int, n3: Int, n4: Int)(f: (Int, Int, Int, Int) => T): Array[Array[Array[Array[T]]]] =
     tabulate(n1)(i1 => tabulate(n2, n3, n4)(f(i1, _, _, _)))
 
-  /** A five-dimensional array containing values of a given function over
+  /** Returns a five-dimensional array containing values of a given function over
    *  ranges of integer values starting from 0.
    *
    *  @param   n1  the number of elements in the 1st dimension
@@ -325,20 +353,20 @@ object Array extends FallbackArrayBuilding {
   def tabulate[T: ClassManifest](n1: Int, n2: Int, n3: Int, n4: Int, n5: Int)(f: (Int, Int, Int, Int, Int) => T): Array[Array[Array[Array[Array[T]]]]] =
     tabulate(n1)(i1 => tabulate(n2, n3, n4, n5)(f(i1, _, _, _, _)))
 
-  /** An array containing a sequence of increasing integers in a range.
+  /** Returns an array containing a sequence of increasing integers in a range.
    *
    *  @param from the start value of the array
-   *  @param end the end value of the array (the first value NOT returned)
+   *  @param end the end value of the array, exclusive (in other words, this is the first value '''not''' returned)
    *  @return  the array with values in range `start, start + 1, ..., end - 1`
-   *  up to, but exclusding, `end`.
+   *  up to, but excluding, `end`.
    */
   def range(start: Int, end: Int): Array[Int] = range(start, end, 1)
 
-  /** An array containing equally spaced values in some integer interval.
+  /** Returns an array containing equally spaced values in some integer interval.
    *
    *  @param start the start value of the array
-   *  @param end   the end value of the array (the first value NOT returned)
-   *  @param step  the increment value of the array (must be positive or negative)
+   *  @param end   the end value of the array, exclusive (in other words, this is the first value '''not''' returned)
+   *  @param step  the increment value of the array (may not be zero)
    *  @return      the array with values in `start, start + step, ...` up to, but excluding `end`
    */
   def range(start: Int, end: Int, step: Int): Array[Int] = {
@@ -354,11 +382,11 @@ object Array extends FallbackArrayBuilding {
     b.result
   }
 
-  /** An array containing repeated applications of a function to a start value.
+  /** Returns an array containing repeated applications of a function to a start value.
    *
    *  @param start the start value of the array
    *  @param len   the number of elements returned by the array
-   *  @param f     the function that's repeatedly applied
+   *  @param f     the function that is repeatedly applied
    *  @return      the array returning `len` values in the sequence `start, f(start), f(f(start)), ...`
    */
   def iterate[T: ClassManifest](start: T, len: Int)(f: T => T): Array[T] = {
@@ -379,17 +407,17 @@ object Array extends FallbackArrayBuilding {
     b.result
   }
 
-  /** This method is called in a pattern match { case Seq(...) => }.
+  /** Called in a pattern match like `{ case Array(x,y,z) => println('3 elements')}`.
    *
    *  @param x the selector value
-   *  @return  sequence wrapped in an option, if this is a Seq, otherwise none
+   *  @return  sequence wrapped in a [[scala.Some]], if x is a Seq, otherwise `None`
    */
   def unapplySeq[T](x: Array[T]): Option[IndexedSeq[T]] =
     if (x == null) None else Some(x.toIndexedSeq)
     // !!! the null check should to be necessary, but without it 2241 fails. Seems to be a bug
     // in pattern matcher.
 
-  /** Create an array containing several copies of an element.
+  /** Creates an array containing several copies of an element.
    *
    *  @param n    the length of the resulting array
    *  @param elem the element composing the resulting array
@@ -406,8 +434,8 @@ object Array extends FallbackArrayBuilding {
     a
   }
 
-  /** Create an array containing the values of a given function <code>f</code>
-   *  over given range <code>[0..n)</code>
+  /** Creates an array containing the values of a given function `f`
+   *  over given range `[0..n)`
    */
   @deprecated("use `Array.tabulate' instead")
   def fromFunction[T: ClassManifest](f: Int => T)(n: Int): Array[T] = {
@@ -420,37 +448,37 @@ object Array extends FallbackArrayBuilding {
     a
   }
 
-  /** Create an array containing the values of a given function <code>f</code>
-   *  over given range <code>[0..n1, 0..n2)</code>
+  /** Creates an array containing the values of a given function `f`
+   *  over given range `[0..n1, 0..n2)`
    */
   @deprecated("use `Array.tabulate' instead")
   def fromFunction[T: ClassManifest](f: (Int, Int) => T)(n1: Int, n2: Int): Array[Array[T]] =
     fromFunction(i => fromFunction(f(i, _))(n2))(n1)
 
-  /** Create an array containing the values of a given function <code>f</code>
-   *  over given range <code>[0..n1, 0..n2, 0..n3)</code>
+  /** Creates an array containing the values of a given function `f`
+   *  over given range `[0..n1, 0..n2, 0..n3)`
    */
   @deprecated("use `Array.tabulate' instead")
   def fromFunction[T: ClassManifest](f: (Int, Int, Int) => T)(n1: Int, n2: Int, n3: Int): Array[Array[Array[T]]] =
     fromFunction(i => fromFunction(f(i, _, _))(n2, n3))(n1)
 
-  /** Create an array containing the values of a given function <code>f</code>
-   *  over given range <code>[0..n1, 0..n2, 0..n3, 0..n4)</code>
+  /** Creates an array containing the values of a given function `f`
+   *  over given range `[0..n1, 0..n2, 0..n3, 0..n4)`
    */
   @deprecated("use `Array.tabulate' instead")
   def fromFunction[T: ClassManifest](f: (Int, Int, Int, Int) => T)(n1: Int, n2: Int, n3: Int, n4: Int): Array[Array[Array[Array[T]]]] =
     fromFunction(i => fromFunction(f(i, _, _, _))(n2, n3, n4))(n1)
 
-  /** Create an array containing the values of a given function <code>f</code>
-   *  over given range <code>[0..n1, 0..n2, 0..n3, 0..n4, 0..n5)</code>
+  /** Creates an array containing the values of a given function `f`
+   *  over given range `[0..n1, 0..n2, 0..n3, 0..n4, 0..n5)`
    */
   @deprecated("use `Array.tabulate' instead")
   def fromFunction[T: ClassManifest](f: (Int, Int, Int, Int, Int) => T)(n1: Int, n2: Int, n3: Int, n4: Int, n5: Int): Array[Array[Array[Array[Array[T]]]]] =
     fromFunction(i => fromFunction(f(i, _, _, _, _))(n2, n3, n4, n5))(n1)
 }
 
-/** This class represents polymorphic arrays. <code>Array[T]</code> is Scala's representation
- *  for Java's <code>T[]</code>.
+/** Represents polymorphic arrays. `Array[T]` is Scala's representation
+ *  for Java's `T[]`.
  *
  *  @author Martin Odersky
  *  @version 1.0
@@ -518,17 +546,17 @@ final class Array[T](_length: Int) {
 
   /** The element at given index.
    *  <p>
-   *    Indices start a <code>0</code>; <code>xs.apply(0)</code> is the first
-   *    element of array <code>xs</code>.
+   *    Indices start a `0`; `xs.apply(0)` is the first
+   *    element of array `xs`.
    *  </p>
    *  <p>
-   *    Note the indexing syntax <code>xs(i)</code> is a shorthand for
-   *    <code>xs.apply(i)</code>.
+   *    Note the indexing syntax `xs(i)` is a shorthand for
+   *    `xs.apply(i)`.
    *  </p>
    *
    *  @param i   the index
-   *  @throws ArrayIndexOutOfBoundsException if <code>i < 0</code> or
-   *          <code>length <= i</code>
+   *  @throws ArrayIndexOutOfBoundsException if `i < 0` or
+   *          `length <= i`
    */
   def apply(i: Int): T = throw new Error()
 
@@ -536,18 +564,18 @@ final class Array[T](_length: Int) {
    *    Update the element at given index.
    *  </p>
    *  <p>
-   *    Indices start a <code>0</code>; <code>xs.apply(0)</code> is the first
-   *    element of array <code>xs</code>.
+   *    Indices start a `0`; `xs.apply(0)` is the first
+   *    element of array `xs`.
    *  </p>
    *  <p>
-   *    Note the indexing syntax <code>xs(i) = x</code> is a shorthand
-   *    for <code>xs.update(i, x)</code>.
+   *    Note the indexing syntax `xs(i) = x` is a shorthand
+   *    for `xs.update(i, x)`.
    *  </p>
    *
    *  @param i   the index
-   *  @param x   the value to be written at index <code>i</code>
-   *  @throws ArrayIndexOutOfBoundsException if <code>i < 0</code> or
-   *          <code>length <= i</code>
+   *  @param x   the value to be written at index `i`
+   *  @throws ArrayIndexOutOfBoundsException if `i < 0` or
+   *          `length <= i`
    */
   def update(i: Int, x: T) { throw new Error() }