Is there an expression for an infinite iterator?

Is there a straight-forward expression that can produce an infinite iterator?

This is a purely theoretical question. No need for a "practical" answer here :)

For example, it is easy to use a generator expression to make a finite iterator:

my_gen = (0 for i in range(42))

However, to make an infinite one I need to "pollute" my namespace with a bogus function:

def _my_gen():
    while True:
        yield 0
my_gen = _my_gen()

Doing things in a separate file and import-ing later doesn't count.

I also know that itertools.repeat does exactly this. I'm curious if there is a one-liner solution without that.

Solution

for x in iter(int, 1): pass

Two-argument iter = zero-argument callable + sentinel value
int() always returns 0

Therefore, iter(int, 1) is an infinite iterator. There are obviously a huge number of variations on this particular theme (especially once you add lambda into the mix). One variant of particular note is iter(f, object()), as using a freshly created object as the sentinel value almost guarantees an infinite iterator regardless of the callable used as the first argument.