On Thu, Sep 29, 2016 at 1:53 PM, Steve D'Aprano <steve+pyt...@pearwood.info> wrote: > John Cook suggests that functional programming gets harder and harder to do > right (both for the compiler and for the programmer) as you asymptotically > approach 100% pure, and suggests the heuristic that (say) 85% pure is the > sweet spot: functional in the small, object oriented in the large. > > http://www.johndcook.com/blog/2009/03/23/functional-in-the-small-oo-in-the-large/ > > > I agree. I find that applying functional techniques to individual methods > makes my classes much better: > > - local variables are fine; > - global variables are not; > - global constants are okay; > - mutating the state of the instance should be kept to the absolute minimum; > - and only done from a few mutator methods, not from arbitrary methods; > - attributes should *usually* be passed as arguments to methods, not > treated as part of the environment.
I would agree with you. "Functional programming" is not an alternative to imperative or object-oriented programming; it's a style, it's a set of rules, that make small functions infinitely easier to reason about, test, and debug. My points about practicality basically boil down to the same thing as you were saying - 100% pure is infinitely hard. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
