General Purpose Pipeline library?

[Skip Montanaro]

> I feel like I'm reinventing a wheel here.  I was wondering if there's already something that exists?

I've wondered from time-to-time about using shell pipeline notation
within Python. Maybe the grapevine package could be a starting point?
I realize that's probably not precisely what you're looking for, but
maybe it will give you some ideas. (I've never used it, just stumbled
on it with a bit of poking around.)

Skip