The code is the documentation

Yeah that's right, it is. If you're a working programming, you spend a good amount of your time writing in a language few people understand and then a bunch of time writing in english to help people understand what the hell your run-on overly complicated login function does. What you probably did is believe that you'd document it later and then you tried to be clever. That was a mistake; you're not Shakespeare or Chaucer. Your cut and paste, cargo-culted crap reads like a 4th grade essay on the death penalty. There needs to be a serious change on how we look at the work products produced from programming.

When you buy a cabinet, a chair, or anything from a master craftsman, do they design it with some clever way to sit in it and then write a manual in terrible english prose to explain how you should be sitting in it? NO!... Well at least not most of them, maybe some douche-bag avant-garde retro-bauhaus designer would, but who cares. Let's face it, in life most of what you do will not be sophisticated or clever or even fun. It will be work. The difference is not between how you deal with the opportunity for creativity but the opportunity for craftsmanship.

There are a few things that I've noticed in my short term in industry

• You will do more craft than art in life (even if you're an artist)
• If you do something at the limits of your comprehension, you will not understand it later
• Cleverness leads to sadness

After writing those down a few days ago, I've had some time to reflect on what that all means. It also gave me time to decide that the first and last concepts, while important, are just not as useful as the second; I'm throwing them away for now. Really the most important thing you need to remember is:

If you do something at the limits of your comprehension, you will not understand it later

On second thought, maybe this post was the limits of what I can understand; I should stop trying to say something profound...

Being lazy in Python

One of my favorite features of Haskell is its lazy evaluation of list comprehensions. This makes it possible to take the nth position item of a list without first having to calculate the entire list. Pretty sweet if you want to reason of infinite data sets such as the Fibonacci numbers or primes. In a perfect world, I'd be writing Haskell all the time. However, that's just not possible. Python is far more popular, is installed by default on many OSes and can make some tasks very simple. So really, I want lazy list evaluations in Python. The only way to implement this without hacking up the actual interpreters object space is to mess with iterators. So I've implemented the Fibonacci sequence as an iterator. Essentially, I use the next parameter to move over the list of Fibonacci numbers and calculate the next one. I then store any numbers which I have already calculated to prevent extra work. I then use that pre-calculated list along with further calculation to implement list subscripting and contains. One thing to note is that itertools.takewhile will continue iteration for one through the failing condition, not up to. Hence the existence of a rollback function. Overall it was a fun exercise on using iterators and who knows, maybe it's actually useful.

from itertools import takewhile


class Fib(object):
    i = 0
    items = list()

    def __init__(self):
        self.n = 0
        self.n_1 = 1

    def __contains__(self, item):
        if item in self.items:
            return True
        else:
            self.items += list(takewhile(lambda x: x <= item, self))
            self._rollback()
            return self.items[-1]

    def __getitem__(self, key):
        if key <= len(self.items):
            return self.items[key - 1]
        else:
            self.items += list(takewhile(lambda x: self.i < key - 1, self))
            self._rollback()
            return self.items[-1]

    def __iter__(self):
        return self

    def next(self):
        next = self.n + self.n_1
        self.n = self.n_1
        self.n_1 = next
        self.i += 1
        return next

    def _rollback(self):
        """
        When iteration gets stopped by takewhile we've gone one too far
        so it needs to be backed up one
        """
        self.n = self.items[-2]
        self.n_1 = self.items[-1]
        self.i -= 1

Update: I've got a gist going of this which includes some bug fixes for slicing.