From 96fd08897359e2851aad31b7b515225dd02b0195 Mon Sep 17 00:00:00 2001
From: Lex Spoon <lex@lexspoon.org>
Date: Fri, 23 Mar 2007 16:46:49 +0000
Subject: - toString() on large collections now only prints

  a few of the elements
- all maps now have getOrElse
- mutable maps now have getOrElsePut
---
 src/library/scala/Seq.scala                    | 13 ++++++++++++-
 src/library/scala/collection/Map.scala         | 25 ++++++++++++++++++++++---
 src/library/scala/collection/Set.scala         | 13 ++++++++++---
 src/library/scala/collection/mutable/Map.scala | 11 +++++++++++
 4 files changed, 55 insertions(+), 7 deletions(-)

(limited to 'src/library')

diff --git a/src/library/scala/Seq.scala b/src/library/scala/Seq.scala
index bdf2db2869..2dd89b5762 100644
--- a/src/library/scala/Seq.scala
+++ b/src/library/scala/Seq.scala
@@ -263,7 +263,18 @@ trait Seq[+A] extends AnyRef with PartialFunction[Int, A] with Iterable[A] {
    *
    *  @return a string representation of this sequence.
    */
-  override def toString() = mkString(stringPrefix+"(", ",", ")")
+  override def toString() = {
+    val middle =
+      if(length <= 20)
+        mkString(",")
+      else {
+        val topr = 2
+        elements.take(topr).mkString(",") +
+            (", and " + (length - topr) + " more...")
+      }
+    stringPrefix + "(" + middle + ")"
+  }
+
 
   /** Defines the prefix of the string representation.
    */
diff --git a/src/library/scala/collection/Map.scala b/src/library/scala/collection/Map.scala
index 6b7e7cd0b1..d10b063d21 100644
--- a/src/library/scala/collection/Map.scala
+++ b/src/library/scala/collection/Map.scala
@@ -50,6 +50,15 @@ trait Map[A, +B] extends PartialFunction[A, B] with Iterable[(A, B)] {
    */
   def get(key: A): Option[B]
 
+  /** Check if this map maps <code>key</code> to a value.
+    *  Return that value if it exists, otherwise return <code>default</code>.
+    */
+  def getOrElse[B2 >: B](key: A, default: B2): B2 =
+    get(key) match {
+      case Some(v) => v
+      case None => default
+    }
+
   /** Is this an empty map?
    *
    *  @return <code>true</code> iff the map is empty.
@@ -139,10 +148,20 @@ trait Map[A, +B] extends PartialFunction[A, B] with Iterable[(A, B)] {
 
   /** Creates a string representation for this map.
    *
-   *  @return    a string showing all mappings
+   *  @return    a string showing all mappings, or a subset of them
+   *                  if the map is large.
    */
-  override def toString() =
-    elements.toList.map(kv => kv._1 + " -> " + kv._2).mkString("Map(", ", ", ")")
+  override def toString() = {
+     def elem2str(kv: (A, B)) = kv._1 + " -> " + kv._2
+     if(size <= 20)
+       elements.map(elem2str ).mkString("Map(", ", ", ")")
+     else {
+       val topr = 2
+       val initStrs = elements.take(topr).map(elem2str)
+       initStrs.mkString("Map(", ", ",
+           ", and " + (size - topr) + " more ...)")
+     }
+  }
 
   /** The default value for the map, returned when a key is not found
    *  The method implemented here yields an error,
diff --git a/src/library/scala/collection/Set.scala b/src/library/scala/collection/Set.scala
index 94cb1d9256..58e9640704 100644
--- a/src/library/scala/collection/Set.scala
+++ b/src/library/scala/collection/Set.scala
@@ -93,8 +93,15 @@ trait Set[A] extends (A => Boolean) with Iterable[A] {
 
   /** Returns a string representation of this set.
    *
-   *  @return a string showing all elements of this set.
+   *  @return a string showing all elements of this set, or a subset
+   *     of them if the set is large.
    */
-  override def toString(): String = mkString("Set(", ", ", ")")
-
+  override def toString(): String =
+    if(size <= 20)
+      mkString("Set(", ", ", ")")
+    else {
+      val topr = 2
+      elements.take(topr).mkString("Set(", ", ",
+          (", and " + (size - topr) + " more...)"))
+    }
 }
diff --git a/src/library/scala/collection/mutable/Map.scala b/src/library/scala/collection/mutable/Map.scala
index 6242eb5fea..4c908aed92 100644
--- a/src/library/scala/collection/mutable/Map.scala
+++ b/src/library/scala/collection/mutable/Map.scala
@@ -159,6 +159,17 @@ trait Map[A, B] extends AnyRef
    */
   def clear(): Unit = keys foreach -=
 
+  /** Check if this map maps <code>key</code> to a value.
+     *  Return that value if it exists, otherwise put <code>default</code>
+     * as that key's value and return it.
+     */
+  def getOrElsePut(key: A, default: B): B =
+    get(key) match {
+      case Some(v) => v
+      case None => this(key) = default; default
+    }
+
+
   /** This function transforms all the values of mappings contained
    *  in this map with function <code>f</code>.
    *
-- 
cgit v1.2.3