At the beginning I also thought to have 4, instead of 0. The problem is that if you put 4 and you have an object with and instVar that it is a SmallInteger, it will be counted twice, when actually it is only one.
That's why I thoguht 0 was better, since I want the really occupated memory. On the other hand, if you do "4 sizeInMemory" and see zero, I have to admit it is a litlte confusing.
The problem is that if I do for example:
Class >> spaceForInstances
| totalSize |
totalSize := 0.
self allInstancesDo: [ :inst |
totalSize := totalSize + inst sizeInMemory.
].
^ totalSize
SmallInteger spaceForInstances ->> 0
So I don't know...maybe we have to answer 4 instead of 0?
Adrian what do you think?
>
> - In the line contentBytes := contentBytes + (self basicSize * bytesPerElement), why is contentBytes added because it should be always 0 because self class instSize should return 0 in case of variable classes. Or do I miss something?
You can have instance variables in variable classes:
ArrayedCollection variableSubclass: #TallyArray
instanceVariableNames: 'tally'
classVariableNames: ''
poolDictionaries: ''
category: 'Collections-Arrayed'
TallyArray instSize 1
(TallyArray new: 5) basicSize 5
Sure, they're not used very often in Squeak/Pharo since become: is so slow, but there's no theoretical reason why you can't for example implement Set as a variable subclass with a tally inst var.
>
> - Please remove the inline comment "inst vars"; if a comment is needed it should go into the main comment.
I agree, should be self-explanatory.