list comprehensions put non-names into namespaces!

[Lonnie Princehouse]

List comprehensions appear to store their temporary result in a
variable named "_[1]" (or presumably "_[2]", "_[3]" etc for nested
comprehensions)

In other words, there are variables being put into the namespace with
illegal names (names can't contain brackets).  Can't someone come up
with a better hack than this?  How about using "_1", "_2", etc, or
actually making "_" a list of lists and using the real first, second,
third elements?  This is an unexpected wrench in the works for people
trying to implement custom global namespaces.

Illustration:

class custom_namespace(dict):
  def __getitem__(self, i):
    print "GET", i
    return dict.__getitem__(self, i)

eval("[x for x in range(10)]", custom_namespace())