On Tue, Oct 18, 2016 at 9:50 PM, Rustom Mody <rustompm...@gmail.com> wrote: > Now we can functionalize all this by making 'the world' as a parameter to our > functions. > Greg talks of this as do other writings on functional IO > I personally find talking of 'world' as though its an object in my little > world to be a sleight of hand.
There is some value in this concept. If you're trying to unit-test something, you need to be able to pin down all the inputs and outputs of a piece of code. Thus, when you document that code, you need to acknowledge that "the world" is one of its inputs - and that unit testing it requires either access to said world, or a mocked version of the significant parts of it. Doesn't magically make the function pure, except in the trivial and useless sense that mutable globals just count as inputs and outputs, and thus all functions are pure. ChrisA -- https://mail.python.org/mailman/listinfo/python-list