Chris Muller uploaded a new version of Collections to project The Inbox:
http://source.squeak.org/inbox/Collections-cmm.576.mcz

==================== Summary ====================

Name: Collections-cmm.576
Author: cmm
Time: 24 July 2014, 10:39:06.452 am
UUID: 17b60ac6-55b3-4706-b1c8-d826e6ad5657
Ancestors: Collections-eem.575

When a SequenceableCollection contains duplicate keys, #findBinaryIndex:do:ifNone: should answer the index of the _earliest_.

=============== Diff against Collections-eem.575 ===============

Item was changed:
  ----- Method: SequenceableCollection>>findBinaryIndex:do:ifNone: (in category 'enumerating') -----
+ findBinaryIndex: aBlock do: actionBlock ifNone: exceptionBlock 
- findBinaryIndex: aBlock do: actionBlock ifNone: exceptionBlock
  	"Search for an element in the receiver using binary search.
  	The argument aBlock is a one-element block returning
  		0 	- if the element is the one searched for
  		<0	- if the search should continue in the first half
  		>0	- if the search should continue in the second half
  	If found, evaluate actionBlock with the index as argument
  	If no matching element is found, evaluate exceptionBlock,
  	with the indexes of the 'bounding' elements as optional
  	arguments. 	Warning: Might give invalid indexes, see
  	examples below.
  	Examples:
+ 		#(1 3 5 7 11 11 15 23)
- 		#(1 3 5 7 11 15 23)
  			findBinaryIndex: [ :arg | 11 - arg ]
  			do: [ :found | found ]
  			ifNone: [ :a :b | ('between: ', {a. b} printString)]
  		#(1 3 5 7 11 15 23)
  			findBinaryIndex: [ :arg | 12 - arg ]
  			do: [ :found | found ]
  			ifNone: [ :a :b | ('between: ', {a. b} printString) ]
  		#(1 3 5 7 11 15 23) d
  			findBinaryIndex: [ :arg | 0.5 - arg ]
  			do: [ :found | found ]
  			ifNone: [ :a :b | ('between: ', {a. b} printString) ]
  		#(1 3 5 7 11 15 23)
  			findBinaryIndex: [ :arg | 25 - arg ]
  			do: [ :found | found ]
  			ifNone: [ :a :b | ('between: ',{a. b} printString) ]
  	"
  	| index low high |
  	low := 1.
  	high := self size.
+ 	[ index := high + low // 2.
+ 	low > high ] whileFalse:
+ 		[ | test |
+ 		test := aBlock value: (self at: index).
+ 		test = 0
+ 			ifTrue:
+ 				[ "In case there are duplicate keys, walk backward to the first."
+ 				[ index > 1 and: [ (aBlock value: (self at: index - 1)) = 0 ] ] whileTrue: [ index := index - 1 ].
+ 				^ actionBlock value: index ]
+ 			ifFalse:
+ 				[ test > 0
- 	[
- 		index := high + low // 2.
- 		low > high ] whileFalse: [
- 			| test |
- 			test := aBlock value: (self at: index).
- 			test = 0 
- 				ifTrue: [ ^actionBlock value: index ]
- 				ifFalse: [ test > 0
  					ifTrue: [ low := index + 1 ]
  					ifFalse: [ high := index - 1 ] ] ].
+ 	^ exceptionBlock
+ 		cull: high
+ 		cull: low!
- 	^exceptionBlock cull: high cull: low!