--- a/ReindexedCollection.st	Fri May 14 13:39:41 2004 +0200
+++ b/ReindexedCollection.st	Mon Jun 07 11:05:31 2004 +0200
@@ -15,6 +15,10 @@
     with in linear algorithm.  
     The elements in the ReindexedCollection are elements in the sequenceable collection at 
     some start to some stop at some step.  
+
+    ReindexedCollection allows for efficient use of first/rest-like algorithms (i.e. aka Lisp)
+    applied to Sequenceable collections, as they avoid element-copying.
+
     See class side examples.
 
     [Instance Variables:]
@@ -182,6 +186,87 @@
     self shouldNotImplement
 ! !
 
+!ReindexedCollection methodsFor:'converting-reindexed'!
+
+from:startIndex
+    "return a new collection representing the receivers elements starting at startIndex."
+
+    interval step == 1 ifTrue:[
+        ^ ReindexedCollection 
+            on:sequence 
+            from:(interval start + startIndex - 1) 
+            to:(interval stop)
+            by:(interval step)
+    ].
+    "could be more intelligent here..."
+    ^ super from:startIndex
+
+    "
+     |coll cdr cddr cdddr|
+
+     coll := #(1 2 3 4 5 6 7 8 9 10).
+     cdr := coll from:2.            
+     cddr := cdr from:2.        
+     cdddr := cddr from:2.
+    "
+!
+
+from:startIndex to:stopIndex
+    "return a new collection representing the receivers elements 
+     starting at startIndex upTo and including endIndex."
+
+    interval step == 1 ifTrue:[
+        ^ ReindexedCollection 
+            on:sequence 
+            from:(interval start + startIndex - 1) 
+            to:((interval start + stopIndex - 1) min:interval stop)
+            by:1
+    ].
+    "could be more intelligent here..."
+    ^ super from:startIndex to:stopIndex
+
+    "
+     |coll cdrButLast cddrButLast2 cdddrButLast3|
+
+     coll := #(1 2 3 4 5 6 7 8 9 10).
+     cdrButLast := coll from:2 to:9.             
+     cddrButLast2 := cdrButLast from:2 to:7.          
+     cdddrButLast3 := cddrButLast2 from:2 to:5.     
+    "
+
+    "
+     |coll cdrButLast cddrButLast2 cdddrButLast3|
+
+     coll := 1 to:100.
+     cdrButLast := coll from:2 to:99.             
+     cddrButLast2 := cdrButLast from:2 to:97.          
+     cdddrButLast3 := cddrButLast2 from:2 to:95.     
+    "
+!
+
+to:stopIndex
+    "return a new collection representing the receivers elements upTo and including endIndex."
+
+    interval step == 1 ifTrue:[
+        ^ ReindexedCollection 
+            on:sequence 
+            from:(interval start) 
+            to:((interval start + stopIndex - 1) min:interval stop)
+            by:1
+    ].
+    "could be more intelligent here..."
+    ^ super to:stopIndex
+
+    "
+     |coll butLast butLast2 butLast3|
+
+     coll := #(1 2 3 4 5 6 7 8 9 10).
+     butLast := coll to:9.              
+     butLast2 := butLast to:8.          
+     butLast3 := butLast2 to:7.     
+    "
+! !
+
 !ReindexedCollection methodsFor:'initialization'!
 
 initialize: aSequence from: start to: stop by: step 
@@ -205,5 +290,5 @@
 !ReindexedCollection class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libbasic2/ReindexedCollection.st,v 1.2 2003-05-04 17:10:57 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libbasic2/ReindexedCollection.st,v 1.3 2004-06-07 09:05:31 cg Exp $'
 ! !