[Python-Dev] Py2.6 buildouts to the set API

["Martin v. Löwis"]

> * New method (proposed by Shane Holloway):  s1.isdisjoint(s2).
> Logically equivalent to "not s1.intersection(s2)" but has an
> early-out if a common member is found.  The speed-up is potentially
> large given two big sets that may largely overlap or may not
> intersect at all.  There is also a memory savings since a new set
> does not have to be formed and then thrown away.

I'd rather see iterator versions of the set operations. Then you
could do

def isempty(i):
  try:
    i.next()
  except StopIteration:
    return True
  else:
    return False

if isempty(s1.iter_intersection(s2)):
  ...

> * Additional optional arguments for basic set operations to allow
> chained operations.  For example, s=s1.union(s2, s3, s4) would be
> logically equivalent to s=s1.union(s2).union(s3).union(s4) but would
> run faster because no intermediate sets are created, copied, and
> discarded.  It would run as if written:  s=s1.copy(); s.update(s2);
> s.update(s3); s.update(s4).

I'd rather see this as collections.bigunion.

> * Make sets listenable for changes (proposed by Jason Wells):

-1, IAGNI.

Martin