--- a/Collection.st	Fri Apr 07 10:08:19 2000 +0200
+++ b/Collection.st	Fri Apr 07 10:09:58 2000 +0200
@@ -10,6 +10,8 @@
  hereby transferred.
 "
 
+"{ Package: 'stx:libbasic' }"
+
 Object subclass:#Collection
 	instanceVariableNames:''
 	classVariableNames:'InvalidKeySignal EmptyCollectionSignal ValueNotFoundSignal
@@ -1851,6 +1853,10 @@
 
 !Collection methodsFor:'queries'!
 
+defaultElement
+    ^  nil
+!
+
 isCollection
     "return true, if the receiver is some kind of collection;
      true is returned here - the method is redefined from Object."
@@ -1871,6 +1877,25 @@
     "Created: 13.4.1996 / 12:35:55 / cg"
 !
 
+isSortedBy:aBlock
+    "return true, if my elements are sorted (already) by the given criterion (sortBlock).
+     Collections which hold their elements in sorted order
+     should return true. Some algorithms (quicksort) degenerate when 
+     operating on sorted collections and can be avoided if this information
+     is given. The default returned here (false) should not hurt.
+     I.e. you should NEVER depend on that in your application."
+
+    ^ false
+
+!
+
+isSortedCollection
+    "return true, if the receiver is a sortedCollection."
+
+    ^ false
+
+!
+
 longestCommonPrefix
     "return the longest common prefix of my elements.
      Typically used with string collections."
@@ -2081,6 +2106,6 @@
 !Collection class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libbasic/Collection.st,v 1.97 2000-02-17 11:05:15 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libbasic/Collection.st,v 1.98 2000-04-07 08:09:58 cg Exp $'
 ! !
 Collection initialize!

--- a/SortedCollection.st	Fri Apr 07 10:08:19 2000 +0200
+++ b/SortedCollection.st	Fri Apr 07 10:09:58 2000 +0200
@@ -10,6 +10,8 @@
  hereby transferred.
 "
 
+"{ Package: 'stx:libbasic' }"
+
 OrderedCollection subclass:#SortedCollection
 	instanceVariableNames:'sortBlock'
 	classVariableNames:'DefaultSortBlock'
@@ -302,7 +304,7 @@
 
     |addedCollection s|
 
-    (aCollection isSorted
+    (aCollection isSortedCollection
     and:[aCollection sortBlock == sortBlock]) ifTrue:[
         addedCollection := aCollection
     ] ifFalse:[
@@ -393,7 +395,7 @@
     newContentsArray := Array new:(n1 + n2).
     destIndex := 1.
 
-    aSortedCollection isSorted ifTrue:[
+    (aSortedCollection isSortedBy:sortBlock) ifTrue:[
         contentsArray2 := aSortedCollection contentsArray.
         srcIndex2 := aSortedCollection firstIndex.
     ] ifFalse:[
@@ -623,9 +625,24 @@
 !SortedCollection methodsFor:'queries'!
 
 isSorted
+    "return true. if my elements are sorted"
+
     ^ true
+!
+
+isSortedBy:aBlock
+    "return true, if my elements are sorted (already) by the given criterion (sortBlock)."
 
-    "Created: 13.4.1996 / 12:36:29 / cg"
+    aBlock == sortBlock ifTrue:[^ true].
+    ^ super isSortedBy:aBlock
+
+
+!
+
+isSortedCollection
+    "return true. if I am a sorted collection"
+
+    ^ true
 ! !
 
 !SortedCollection methodsFor:'searching'!
@@ -797,6 +814,6 @@
 !SortedCollection class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libbasic/SortedCollection.st,v 1.43 1999-12-02 11:21:49 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libbasic/SortedCollection.st,v 1.44 2000-04-07 08:09:30 cg Exp $'
 ! !
 SortedCollection initialize!