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 2010/5/3 Germán Leiva <leivagerman@gmail.com>:
Hi, this is my first post (please be gentle xD)
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 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)? For example, the implementation of #collect: in SortedCollection returns an OrderedCollection (in the current image) and in other dialects the message #collect: when the receiver is a Set returns a Bag ...
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 Cordially, -- Germán Leiva LeivaGerman@gmail.com
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