commit a021fd4bd4f9251c67292dae202dc30ae4747368
Author: Paolo Bonzini <address@hidden>
Date:   Tue Apr 13 17:27:44 2010 +0200

    fix ROE breakage from b85deed and document backwards-incompatible change
    
    packages/roe:
    2010-04-13  Paolo Bonzini  <address@hidden>
    
    	* Core.st: Do not store intervals, since #first and #last fail
    	when sent to an empty interval.
    
    2010-01-20  Nicolas Petton  <address@hidden>
    2010-01-20  Paolo Bonzini  <address@hidden>

diff --git a/NEWS b/NEWS
index 82e9910..b5965ba 100644
--- a/NEWS
+++ b/NEWS
@@ -98,6 +98,10 @@ o   The old instance-based exception handling has been removed.  Standard
 
 o   Collection>>#anyOne gives an error if the receiver is empty.
 
+o   Interval>>#first and Interval>>#last give an error if the interval is
+    empty (i.e. if start > stop and the step is positive, or start < stop
+    and the step is negative).
+
 o   SequenceableCollection>>#sortBy: was renamed to #sort:.  The old message
     is _not_ provided for backwards-compatibility.
 
diff --git a/packages/roe/ChangeLog b/packages/roe/ChangeLog
index 553f458..73d2a30 100644
--- a/packages/roe/ChangeLog
+++ b/packages/roe/ChangeLog
@@ -1,9 +1,14 @@
-2010-10-20  Nicolas Petton  <address@hidden>
+2010-04-13  Paolo Bonzini  <address@hidden>
+
+	* Core.st: Do not store intervals, since #first and #last fail
+	when sent to an empty interval.
+
+2010-01-20  Nicolas Petton  <address@hidden>
 
 	* Array.st: Add #asArray to SQLRelation>>#for:do:, as RASimpleTuple
 	wants numeric indices.
 
-2010-10-20  Paolo Bonzini  <address@hidden>
+2010-01-20  Paolo Bonzini  <address@hidden>
 
 	* Array.st: Rename #sortBy: -> #sort:.
 
diff --git a/packages/roe/Core.st b/packages/roe/Core.st
index 05c5ed2..5eae140 100644
--- a/packages/roe/Core.st
+++ b/packages/roe/Core.st
@@ -899,14 +899,14 @@ RATransformation subclass: RAProjection [
 
 
 RATransformation subclass: RARange [
-    | interval |
+    | offset limit |
     
     <category: 'Roe-Relations-Core'>
     <comment: nil>
 
     RARange class >> of: aSource from: min to: max [
 	<category: 'instance creation'>
-	^self basicNew setSource: aSource interval: (min to: max)
+	^self basicNew setSource: aSource from: min to: max
     ]
 
     acceptRoeVisitor: aVisitor [
@@ -914,35 +914,31 @@ RATransformation subclass: RARange [
 	^aVisitor visitInterval: self
     ]
 
-    interval [
-	<category: 'accessing'>
-	^interval
-    ]
-
     limit [
 	<category: 'accessing-interval'>
-	^self interval size
+	^limit
     ]
 
     offset [
 	<category: 'accessing-interval'>
-	^self interval first - 1
+	^offset
     ]
 
-    setSource: aRelation interval: anInterval [
+    setSource: aRelation from: start to: stop [
 	<category: 'initializing'>
 	source := aRelation.
-	interval := anInterval
+	offset := start - 1.
+        limit := stop - start + 1
     ]
 
     start [
 	<category: 'accessing-interval'>
-	^self interval first
+	^offset + 1
     ]
 
     stop [
 	<category: 'accessing-interval'>
-	^self interval last
+	^offset + limit
     ]
 ]