> However, some code used #species to answer a very different question: 
> what class should I use to make a new collection like this one in a 
> #collect: or a #select: ?    Sometimes this was OK, but sometimes the 
> answer was different  from the answer that we got from #species.    We 
> decided to uniformly use two methods, emptyCopyOfSize: and 
> emptyCopyOfSameSize , to generate the new collections.  
> emptyCopyOfSameSize was implemented as
> 
>     ^ self  emptyCopyOfSize: self size

This is what other Smalltalk usually call #copyEmpty and #copyEmpty:.

As I said, it works for everything except #reverse and #collect: for 
which you can either use something like #copyEmptyForCollect, or resort 
to #species.

Paolo