On Fri, May 11, 2018 at 12:03 AM, Steven D'Aprano <steve+comp.lang.pyt...@pearwood.info> wrote: > On Thu, 10 May 2018 20:38:39 -0600, Ian Kelly wrote: > >> Would you also contend that generator functions are wrong because they >> pretend to be normal functions? > > You're going to need to be more specific. In what way are they not normal > functions? You call them like normal functions, providing arguments like > normal functions, and receiving a result just like normal functions.
The way that they execute is not like a normal function. If you call one, having read the code but having failed to notice the 'yield', you will be confused by the result. Likewise, if you run a while True loop (or *any* loop, really), having read the code but failed to notice the 'break', you will be confused by the result. The point being that you cannot necessarily infer what a while loop will do just by reading the loop condition, any more than you can know what a function call will return if all you've read are the name and the signature. > If you call a function like iter(), you also get back an iterator, just > as you do when you call a generator. Is iter() not a normal function? Presumably somebody experienced with Python will already know what iter does without needing to read the code. >> def totally_not_a_generator(n): >> while True: >> if n % 2 == 0: >> n //= 2 >> else: >> n = n * 3 + 1 >> stealthily = n >> yield stealthily >> if n == 1: >> return n > > I must admit, I'm a little perplexed. In what way is this totally not a > generator? (To be precise, a generator function.) The inspect module > thinks it is (and so do I): The example was tongue-in-cheek. As suggested by the comment in the part that you cut out where I called it, the code is lying. -- https://mail.python.org/mailman/listinfo/python-list
