Support of algebraic operations on sets

sig siguctua at
Fri Jun 15 12:45:30 UTC 2007

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.

On 15/06/07, Bert Freudenberg <bert at> wrote:
> On Jun 15, 2007, at 13:52 , Gary Chambers wrote:
> > Note that #difference: is the relative complement of the two sets,
> > rather
> > than the symmetric difference.
> > Perhaps we could have a method for that too!
> IMHO that's not nearly as universally useful as the other operations.
> Has anybody ever missed it before? We're not talking about Set theory
> but actual usefulness as a general Collection protocol.
> - Bert -

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