On Jun 15, 2007, at 14:45 , sig wrote:

> actually i missing these operations for dictionaries.
> in current implementation if you diff/union on two dictionaries,
> you'll find out that associations play role as set elements, not keys.
>
> for dictionaries 'a difference: b' i get not exactly what i would  
> expect.

Dictionaries are like other collections - a collection of  
"elements" (the values). The keys are only interesting for accessing  
- like indices on Arrays.  #do: operates on the values. So does  
#select:, and #difference:. You wouldn't expect #difference: on an  
Array to work on its indices, would you?

- Bert -