> Hi, this is my first post (please be gentle xD)

Thanks!

>
> The #collect: message commonly return a new collection like the receiver, but this is really unpractical in some cases
>
> e.g.
> col := Set with: 'one'->1 with: 'two'->2 with: 'dos'->2.
> (col collect: [:each | each value ]) sum

In VW you get the same.

> In this example #sum will return 3 instead of 5 (I searched a test for #sum but I didn�t find it).
>
> Ok, I can use the message #asBag (or something like that) but does the second line have to depend on the type of the receiver (i.e. the type of col)?

I think that this is the invariant for collect: ?

> For example, the implementation of #collect: in SortedCollection returns an OrderedCollection (in the current image)

in VW too

> and in other dialects the message #collect: when the receiver is a Set returns a Bag ...

which ones?

> Basically, what do you think of an implementation like this?
>
> Set >> collect: aBlock
> �"Evaluate aBlock with each of the receiver's elements as the argument.
> �Collect the resulting values into a Bag. Answer the new collection."
> �| newBag |
> �newBag := Bag new: self size.
> �array do: [:each | each ifNotNil: [newBag add: (aBlock value: each)]].
> �^ newBag

True.It can be impractical, but no need to change #collect:
Please use #detectSum:

(Set with: 'one'->1 with: 'two'->2 with: 'dos'->2) detectSum: [:e |e value].
�

or #collect:as:

((Set with: 'one'->1 with: 'two'->2 with: 'dos'->2) collect: [:e |e
value] as: Array) sum.

Nicolas