0006943: Heap equality should be associative

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Category

Severity

Reproducibility

Date Submitted

Last Update

0006943

[Squeak] Collections

minor

always

02-21-08 21:18

02-06-11 23:48

Reporter

nicolas cellier

View Status

public

Assigned To

nicolas cellier

Priority

normal

Resolution

fixed

Status

closed

Product Version

3.10

Summary

0006943: Heap equality should be associative

Description

"This example shows that equality is not associative"

    | anArray heap1 heap2 |
    anArray := #(1 2 3).
    heap1 := Heap withAll: (1 to: 3) sortBlock: [:a :b | a < b].
    heap2 := Heap withAll: (1 to: 3) sortBlock: [:a :b | b > a].
    self assert: (heap1 = anArray) & (heap2 = anArray) ==> (heap1 = heap2)

Additional Information

Heaps do compare their sortBlock.
They are more relax when comparing with their species.

This does happen since their species is Array...
http://lists.squeakfoundation.org/pipermail/squeak-dev/2000-March/011043.html [^]

As noted by Klaus Witzel, why did species change?
Correcting which bug?

Attached Files

Heap-Equality-IsNotAssociative-M6943-Test.1.cs [^] (733 bytes) 02-21-08 21:28

M6943-Heap-Equality-IsNotTransitive-Fix .1.cs [^] (831 bytes) 08-21-10 14:03

Relationships

Notes
(0011858 - 248 - 324 - 324 - 324 - 324 - 324) nicolas cellier 02-21-08 22:12	I'm loosing my maths, #= should be an equivalence relation, reflexive, self assert: (a = a), symmetric, self assert: (a = b) ==> (b = a), transitive, self assert: (a = b) & (b = c) ==> (a = c) Yes Transitive rather than Associative...

(0013836 - 326 - 359 - 359 - 359 - 359 - 359) nicolas cellier 08-21-10 14:07	The fix makes Heap behave like a SortedCollection: 1) re-establish the Heap species -> Heap. 2) collect: does collect:as: Array because there is no guarantee the sortBlock works after transformation 3) select: use #copyEmpty strategy (like OrderedCollection) Beware of load order, a Heap is used in your morphic world...

(0013837 - 117 - 123 - 453 - 453 - 453 - 453) nicolas cellier 08-21-10 15:47	http://source.squeak.org/trunk/Collections-nice.370.mcz [^] http://source.squeak.org/trunk/CollectionsTests-nice.170.mcz [^]

Issue History
Date Modified	Username	Field	Change
02-21-08 21:18	nicolas cellier	New Issue
02-21-08 21:28	nicolas cellier	File Added: Heap-Equality-IsNotAssociative-M6943-Test.1.cs
02-21-08 22:12	nicolas cellier	Note Added: 0011858
08-21-10 14:03	nicolas cellier	File Added: M6943-Heap-Equality-IsNotTransitive-Fix .1.cs
08-21-10 14:07	nicolas cellier	Note Added: 0013836
08-21-10 15:47	nicolas cellier	Status	new => resolved
08-21-10 15:47	nicolas cellier	Fixed in Version	=> trunk
08-21-10 15:47	nicolas cellier	Resolution	open => fixed
08-21-10 15:47	nicolas cellier	Assigned To	=> nicolas cellier
08-21-10 15:47	nicolas cellier	Note Added: 0013837
02-06-11 23:48	leves	Status	resolved => closed

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