On Tue, May 19, 2009 at 12:43 PM, Aaron Rubin
1) Python is three things which the standard was not designed for: One: Object Oriented. Two: Not Hungarian notation Three: Mandatorily uses whitespace as its defintion for code blocks. Let me explain each one in a bit more detail: Object Oriented: Because it is not functional-style programming, but instead OO, you have to give defintion as to what object type you are using before using it. This makes definitions and usage longer than in functional programming (when 80 character widths were invented). PhazeMonkey.Hardware.FrameSource.Abstract.Framegrabber is an example (and not an extreme one) of a class (55 characters already) in a rather large code base.
If you are using more than 5 or 6 levels of indentation you may be doing something wrong. I would guess that your methods are too complex or maybe you are violating the SRP.
Not Hungarian: Not only is Python not Hungarian (in general), but the PEP-8 specifically tells us to use longer, more descriptive variable names. hasInstrumentControllerPhaseDither is an example. Many variables are 15-20 characters and oftentimes longer. How many of these variables can you fit into a line if we are limited to 80?
I'd like to see an example of your variable names. I don't use hungarian notation and my name are usually under 10 characters.
Whitespace: Python is very unique in that it uses whitespace for code blocking. It turns out to be very useful, since it visually cues the reader where code blocks begin and end by mandate. This creates many situations where code starts at the 10th indentation (40 characters in our standard, 80 characters in some Python standards). Even in normal "great design" mode (which takes more time again), you can't help it....your code starts at the 6th indentation level often. (28 characters, more than 30% of 80 characters already gone. Now how many variables or class names can you fit?)
I'd like to see an example of where using 10 levels of indentation is good. I'll bet that it's not easy to test.
Whitespace (2): Because Python uses whitespace as its sole method of code blocking and because this is the visual cue for code blocks, wrapping lines obfuscates this and makes the reader think about whether this whitespace was there for a code block, or a line-wrap. Thinking about intention of code slows us down.
I partially think you're right. Although I have the same problem with long lines that have multiple levels of parens.
2) Many of the libraries that are widely used do not adhere to the 80 character width line standard. wxPython, NumPy and Boa Constructor are a few, but I'm sure there are many, many more. Many libraries do adhere to 80 character line width as well. However, a library which is written in 80 characters still fits the paradigm of those which are wider and therefore backward compliant. In other words, if your tools are geared toward 80 character line widths and you are now looking at a wider width, things become quite difficult. The other way around is fine. 3) Writing new code in 80 character line widths takes more time. If I have to worry about hitting this width, I have to de-concentrate my efforts of writing logical code and concentrate instead on how exactly to format this line of code (where to break it, etc....there are a number of rules attached to wrapping lines of code). Then I have to re-concentrate on the actual task at hand. Alternatively, I can code it up without worrying, then when convenient, take some time to reformat to 80 character width. Either way, more time.
I don't really have this issue. The few seconds a day that I waste formatting code are nothing near the time I waste on YouTube :-)
4) Code searching. IDEs have powerful searching features. They list all the lines of a file (or files) which match the string you are searching for. If things are in one line, this search is meaningful and you can read it like you can code. If a line of code actually spans two (or more) lines of code, the search is no longer contextually useful and you have to click on each item to see what's actually going on. This feature is used heavily in many environments (especially large code bases) to save time, but time is either lost finding the actual context of a found string, or the search tool is avoided altogether because it does not provide meaningful results (i.e. a predictive waste of time)
I would actually like to see tools changed to make this better. Maybe similar to the way unified diff shows a few lines of context.
5) Monitors are getting bigger, wider, cheaper. This allows us to have two files, side-by-side on a screen that are both 120 character width (or even wider), without changing font sizes.
Sure I guess. I am typing this on my EEE 900 which won't like much more than 90 chars. But even at work I put multiple 80 char wide windows side by side.
6) Tools are cheap. Time isn't. Get a second monitor, get a more powerful editor, do whatever it takes to save time. If viewing more information at one time is important, then we should try to make that possible with technology, not time.
Agreed. Use Vim with 80 characters and you will rock out code like never before. I hear Emacs is good too. What are you currently using.
7) Python is designed to be written more like English than other programming languages.
That's news to me.
On another note when we hire new developers I often hear this argument. Once they start coding in Python and using good OO/TDD techniques they realize that it really doesn't matter. Out of curiosity how much Python coding do you do?