Alain M. Lafon

Spoiler: This post is primarily gonna be an excerpt of my bookmarks collection. That’s because more intelligent men than me have already written great articles on the topic of how to become a great Python programmer.

I will focus on four primary topics: Functional programming, performance, testing and code guidelines. When those four aspects merge in one programmer, he or she will gain greatness no matter what.

Functional programming

Writing code in an imperative style has become the de facto standard. Imperative programs consist of statements that describe change of state. While this might sometimes be a performant way of coding, it sometimes isn’t (for example for sake of complexity) – also, it probably is not the most intuitive way when compared with declarative programming.

If you don’t know what I’m talking about, that’s great. Here are some starter articles to get your mind running. But beware, it’s a little like the red pill
– once you tasted functional programming, you don’t want to go back.

• http://www.amk.ca/python/writing/functional
• http://www.secnetix.de/olli/Python/lambda_functions.hawk
• http://docs.python.org/howto/functional.html

Performance

There’s so much talk going on about how inefficient these ‘scripting languages’ (Python, Ruby, …) are, that it’s easy to forget that very often it’s the algorithm chosen by the programmer that leads to horrible runtime behaviour.

Those articles are a great place to get a feel for the ins and outs of Python’s runtime behaviour, so you can get your high performing application writting in a language that is concise and fun to write. And if your manager asks about Python’s performance, don’t forget to mention that the second largest search engine in the world is run by Python – namely Youtube(see Python quotes).

• http://jaynes.colorado.edu/PythonIdioms.html
• http://wiki.python.org/moin/PythonSpeed/PerformanceTips

Testing

Testing is probably one the most misjudged topics in computer science these days. Some programmers really got it and emphasize TDD(test driven development) and it’s successor BDD(behaviour driven development) whereever possible. Others simply don’t feel it yet and think it’s a waste of time. Well, I’m gonna be that guy and tell you: If you haven’t started out on TDD/BDD yet, you have missed out greatly!

It’s not about introducing a technology to replace that release management automaton in your company that mindlessly clicks through the application once in a while, it is about giving you a tool to deeply understand your own problem domain – to really conquer, manipulate and twist it the way you want and need it to be. If you haven’t yet, give it a shot. These articles will give you some impulses:

• http://www.oreillynet.com/lpt/a/5463
• http://www.oreillynet.com/lpt/a/5584
• http://wiki.cacr.caltech.edu/danse/index.php/Unit_testing_and_Integration_testing
• http://docs.python.org/library/unittest.html

Code guidelines

Not all code is created equal. Some can be read and changed by any great programmer out there. But some can only be read and only sometimes changed by the original author – and that maybe only a couple of hours after he or she wrote it. Why is that? Because of missing test coverage (see above) and the lack of proper usage of coding guidelines.

These articles establish an absolute minimum to adhere to. When you follow these, you will write more consise and beautiful code. As a side effect it will be more readable and adaptable by you or anyone else.

• http://www.python.org/dev/peps/pep-0008/
• http://www.fantascienza.net/leonardo/ar/python_best_practices.html

Now go ahead and spread the word. Start with the guy sitting right next to you. Maybe you can go to the next hackathlon or code dojo and start becoming great proficient programmers together!

All the best on your journey.

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Finding the perfect IDE for Python isn’t an easy feat. There are a great many to chose from, but even though some of them offer really nifty features, I can’t help myself but feel attracted to VIM anyway. I feel that no IDE accomplishes the task of giving the comfort of complete power over the code – something is always missing out. This is why I always come back to using IDLE and VIM. Those two seem to be best companions when doing some quick and agile hacking – but when it comes to managing bigger and longer term projects, this combo needs some tweaking. But when it’s done, VIM will be a powerful IDE for Python – including code completion(with pydoc display), graphical debugging, task-management and a project view.

This is where we are going:

So, these are my thoughts on a VIM setup for coding (Python).

Modern GUI VIM implementations like GVIM or MacVIM give the user the opportunity to organize their open files in tabs. This might look convenient, but to me it is rather bad practice, because a second tab will not be in the in the same buffer scope as the first one which takes away from future interaction options between the two. Using MiniBufExplorer, however, gives the user tabs(not only in the GUI, but also in command line) and leaves the classic buffer interaction intact.

Being able to neatly work on multiple files, the user still misses the potential his favourite IDE gives him in visualizing classes, functions and variables. Luckily there are quite a few plugins around to accomplish this task just as well. My favourite one would be TagList. TagList uses Exuberant Ctags for actually generating the tags(note: it really relies on this specific version of ctags – preinstalled implementations on UNIX systems won’t work).

A lot of coders have the habit of using TODO or FIXME statements in their code. Other IDEs often rely on having good third party project management software, but not VIM. There are great plugins like Tasklist reminding the programmer of those lines of code. Tasklist even implements custom lists – to me that’s an incredible productivity gain.

In these times, the programmer knows his or her programming language more or less by interactively finding out what it can do. Therefore code completion(sometimes also called IntelliSense*ugh*) is a major feature. I have heard  many people saying that this is where VIM fails – but luckily they are plain wrong(; In V7, VIM introduced omni completion – given it is configured to recognize Python (if not, this feature is only a plugin away) Ctrl+x Ctrl+o opens a drop down dialog like any other IDE – even the whole Pydoc gets to be displayed in a split window.

Probably the most wanted feature(besides code completion) is debugging graphically. VimPDB is a plugin that lets you do just that(. I acknowledge it is no complete substitution for a full fledged graphical debugger, but I honour the thought that having to rely on a debugger (often), is a hint of bad design.

—

From the eye-candy to the implementation. Don’t worry, it’s no sorcery.

First of all, make sure you have VIM version 7.x installed, compiled with Python support. To check for the second, enter :python print “hello, world” into VIM. If you see an error message like “E319: Sorry, the command is not available in this version”, then it’s time to get a new one. If you’re on a Mac, just install MacVIM(there’s also a binary for the console in /Applications/MacVim.app/Contents/MacOS/). If you’re on Windows, GVIM will suffice(for versions != 2.4 search for the right plugin). If you’re on any other machine, you will probably know how to compile your very own VIM with Python support.

Second, check if you have a plugin directory. In Unix it would typically be located in $HOME/.vim/plugin, in Windows in the Program Files directory. If it doesn’t exist, create it.

Now, let’s start with the MiniBufExplorer. Get it and copy it into your plugin directory. To start it automatically when needed and be able to use it with keyboard and mouse commands, append these lines in your vimrc configuration:

let g:miniBufExplMapWindowNavVim = 1
let g:miniBufExplMapWindowNavArrows = 1
let g:miniBufExplMapCTabSwitchBufs = 1
let g:miniBufExplModSelTarget = 1

For a project view, get TagList and Exuberant Ctags. To install Ctags, unpack it, go into the directory and do a compile/install via:

./configure && sudo make install

Ctags will then be installed in /usr/local/bin. When using a Windows machine, I recommend Cygwin with GCC and Make; it’ll work just fine. If you don’t want to tamper with your original ctags installation, you can propagate the location to VIM by appending the following line to vimrc:

let $Tlist_Ctags_Cmd='/usr/local/bin/ctags'

To install TagList, just drop it into VIMs plugin directory. You will now be able to use the project view by typing the command :TlistToggle.

Tasklist is a simple plugin, too. Copying it into the plugin directory will suffice. I like to have shortcuts and have added

map T :TaskList<CR>
map P :TlistToggle<CR>


to vimrc. Pressing T will then open the TaskList if there are any tasks to process. q quits the TaskList again.

VimPDB is a plugin, as well. Install as before and see the readme for documentation. If it doesn’t work out of the box, watch for the known issues.

To enable code(omni) completion, add this line to your vimrc:

autocmd FileType python set omnifunc=pythoncomplete#Complete

If it doesn’t work then, you’ll need this plugin.

My last two recommondations are setting these lines to comply to PEP 8(Pythons’ style guide) and to have decent eye candy:

set expandtab
set textwidth=79
set tabstop=8
set softtabstop=4
set shiftwidth=4
set autoindent
:syntax on

There are certainly a lot more flags to help productivity, but those will probably be more user specific.

Have fun coding Python while not being bound to a specific IDE, but having all the benefits of VIM bundled with a few helping hands. Enjoy, everyone.

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