Re: [Pharo-dev] hash and Collections

You simply don't modify _objects_ which are used as keys in hashed collections. Or if you do so, you'll have to deal with the consequences yourself. Levente On Fri, 9 Oct 2015, Esteban Lorenzano wrote:

Hi,

Can anyone explain me how this is correct?

Collection>>#hash "Answer an integer hash value for the receiver such that, -- the hash value of an unchanged object is constant over time, and -- two equal objects have equal hash values"

| hash |

hash := self species hash. self size <= 10 ifTrue: [self do: [:elem | hash := hash bitXor: elem hash]]. ^hash bitXor: self size hash

I mean… a hash that changes when I add elements to the collection… how can this work?

Esteban