if __name__ == ‘__main__’ can be nicer!

After many times of writing out this default “main” code, I decided to work out if there is a way that I don’t have to type as much and make it look nicer. Yes, I’m pedantic with code neatness. Here is an example of what I’m talking about:

def main():
    print 'this runs only when executed directly'

if __name__ == '__main__':
    main()

I asked on Stack Overflow, but the general answer was “deal with it”. After a quick discussion of the problem, @dsturnbull and myself worked out that it was possible to import a module and use a decorator in place of this if statement.

The module is called automain, and here is an example of its usage:

from automain import *

@automain
def main():
    print 'this runs only when executed directly'

I threw it on github, and Python Cheese Shop and it can be easy_installed:

easy_install automain

How does it work?
The source code of the decorator looks like this:

def automain(func):
    import inspect
    parent = inspect.stack()[1][0]
    name = parent.f_locals.get('__name__', None)
    if name == '__main__':
        func()

Basically it inspects the parent stack frame, and checks if __name__ is ‘__main__’, then executes the function. Otherwise it does nothing, as expected.

Internet Trolls
Interestingly enough, a random internet troll rated the module 0/5 on Python Cheese Shop and started his comment with:

spookylukey (2011-01-24, 0 points):
Seriously? Is this a joke?

1. Your implementation can’t possible work – it is going to do the same if the module is imported as a library or if it is run as a script.
[..snip..]

All I have to say is that it does work and I find it much better to use. Thanks for the terrible and incorrect feedback though, spookylukey!

Mac App Store dealings with Gravit

The Mac App Store gave me an excuse to try to make money out of my Open Source gravity simulator, Gravit.

I signed up to the Mac Developer Program, packaged Gravit, and uploaded it. Soon after, I got an email mentioning:

2.5 Apps that use non-public APIs will be rejected

The following non-public APIs are included in your application:
CPSSetFrontProcess, CPSGetCurrentProcess and CPSEnableForegroundOperation from the ApplicationServices.framework

Continue reading Mac App Store dealings with Gravit

Gravit universal binary released for Mac OS X

Gravit is an Open Source gravity simulator I started writing in 2003 and worked on it in my spare time until about 2005. It’s written in C and uses OpenGL, SDL and Lua.

Even though Gravit has worked on Mac OS X for a while, I didn’t get around to actually making a bundled application for it until now. Normally you would have had to compile it from source, usually with some tinkering of the source code and build settings.

The UI needs some more work to make it more like an OS X application, but I don’t have time for it at the moment. For now, here is the gravit-0.5.0.dmg universal binary and a quick tutorial on using it. Don’t forget to hold down the fn key when dealing with function keys, and if you have any problems please tweet them at me. Enjoy!

What is the longest word you can type with one hand?

I was looking for random, useless facts on the Internet the other day and found one that said:

“Skepticisms is the longest word that alternates hands when typing.”

This turned out wrong. A friend convinced me to write an application to work it out, and I decided to make it do more…

The application uses the UNIX words file to scan for words. Granted, not all the words actually are real, but it is a good indication.

To cut to the chase, the longest words with one hand on the QWERTY keyboard layout are 12 letters long:

aftereffects, desegregated, desegregates, reverberated, reverberates, stewardesses

These are all left handed words. In fact, there are 57 longer words that can be typed than the longest right handed word. The longest right handed word is “polyphony” with 9 letters. I found this a bit unusual so I decided to graph it (below). With alternating key strokes, the longest words are:

authenticity, enchantment, entitlement, proficiency, shantytowns

These are 12 letters for authenticity and 11 for the rest.

Here are the graphs for QWERTY with left vs right vs alternating sides:

I recall that the Dvorak Simplified Keyboard was designed with alternating hand key strokes in mind. With alternating sides, the highest word count is 14–slightly more than QWERTY’s 12. These words are:

overemphasized, overemphasizes, unpremeditated, verisimilitude

Interestingly enough, the Dvorak layout has very few words that have multiple key presses on the same side of the keyboard. The left side is the most popular with the longest words, at 6 letters, being:

kookie, opaque, papaya, upkeep, yippee, yuppie

The right side has a lowly score of 3 letters, one isn’t even a word:
brr, nth

Here is the Dvorak graph:

Well, come to your own conclusions from this data! I was just curious and slightly bored…

The graphs are made with Google Charts API using the pygooglechart module. If there’s enough interest I’ll throw the code up on github.

Creating an OS X Installer for Python modules and extensions

In the past, people have hassled me to make it easier for them to install my applications and libraries on OS X. I’m not very skilled with OS X, and searching for how to do this task took some time. I’ve made a script that does this in a modular way for Python. Specifically, this article describes the process of making a Python module or extension installer for OS X, similar to the Python installer for Windows.

Continue reading Creating an OS X Installer for Python modules and extensions

Python Google Chart 0.2.1 released

I just released pygooglechart 0.2.1. It has several bug fixes and minor additions, but the major change is that it now supports QR codes. You can quite easily create a QR code with pygooglechart as you can see below.

from pygooglechart import QRChart

# Create a 125x125 QR code chart
chart = QRChart(125, 125)

# Add the text
chart.add_data('Hello, World!')

# "Level H" error correction with a 0 pixel margin
chart.set_ec('H', 0)

# Download
chart.download('qr-hello.png')

This will download a png from the URL:

http://chart.apis.google.com/chart?cht=qr&chs=125×125&chl=Hello%2C%20World%21&chld=H|0

The image downloaded looks like this:

QR codes are new to me. I’ve only seen a QR code on a bus stop advertisement once in Sydney but I’m sure more will pop up.

Wireless Heatmap

Update: WiFi Heat is available on the Google Play Store! For more information, see http://wifiheat.com/.

I wrote an application to generate a wireless (802.11) heat map based on signal strength. The reason for it was to find the best place/area (for my laptop) to be with the highest signal strength. Below is a screenshot of the application (with the ESSID and BSSID removed for security reasons).

This heat map has about 100 samples in it, which are shown as white dots. There is a balcony at the top of the image and the common office area on the right, which was drawn by hand (hence the waviness). As you can see it has pinpointed the location of the access point in the red area.

Continue reading Wireless Heatmap

Create a fast C Python extension with Cython tutorial

Cython is an easy way to create Python extensions in “pseudo-Python” without having to deal with the verboseness of the Python API. It also does not rely on you knowing much of the C language. Cython is based on Pyrex which I have some experience with. This tutorial shows you how to convert a simple Python module to a Python extension.

Continue reading Create a fast C Python extension with Cython tutorial

TracRecaptchaPlugin 0.1.0 – A CAPTCHA plugin for Trac

I decided to make a CAPTCHA plugin for Trac called TracRecaptchaPlugin, to stop spammers using the ticket system. There is an existing Trac plugin to fight spammers, but it still lets through many automated spammers.

The plugin uses the reCAPTCHA service and is serving me well so far. Here’s how it looks within the template:

TracRecaptchaPlugin Screenshot

This is my first publicly released Trac plugin so I’m unsure how it’ll perform out there, so feedback is welcome.

Python Google Chart 0.2.0

I released pygooglechart 0.2.0 this afternoon after several months of patches coming in to add features and fix bugs. The main addition to pygooglechart is automatic data scaling, which is turned on by default. You can also specify the scale range manually:

chart = SimpleLineChart(width, height, x_range=(0, 100), y_range=(0, 100))

Other features are the new API chart types and options. There are 3 new chart types: Map, Google-o-Meter and Radar. Here is an example of using the Map chart type:

import pygooglechart as gc

chart = gc.MapChart(440, 220)
chart.set_colours(('AAAAAA', '30A030', 'A0C030'))
chart.set_codes(['AU', 'US', 'CA', 'BR', 'NZ'])
chart.add_data([1, 0.5, 0.7, 0.3, 0.1])
chart.download('map.png')

Produces the URL:
http://chart.apis.google.com/chart?cht=t&chs=440×220&chd=s:9frSG&chco=AAAAAA,30A030,A0C030&chtm=world&chld=AUUSCABRNZ

And the image:

The Google-o-meter has a funny name. Here is an example of its usage:

import pygooglechart as gc

chart = gc.GoogleOMeterChart(440, 220, y_range=(0, 10))
chart.set_pie_labels(['Awesome'])
chart.add_data([8])
chart.download('gom.png')

It produces this URL:
http://chart.apis.google.com/chart?cht=gom&chs=440×220&chd=s:x&chl=Awesome

And the image:

Well, have fun. Please tweet me for any bugs, patches or feature requests you have.

BetterPrint

I find readability very important when reading data. It saves time and energy. To me, Python’s pprint module is not easy to read in a lot of cases so I made my own. This is how pprint looks like at the moment:

BetterPrint is based on a lot of the source code, which looks about 10 years old. It makes more sense to me to have braces aligned by column rather than jammed together inline. BetterPrint also introduces colour to increase readability even more. As you can see from the following screen shot:

BetterPrint is compatible with Python’s pprint module, so you can simply “import betterprint” aliased as pprint like so:

try:
    import betterprint as pprint
except ImportError:
    import pprint

If you have setuptools installed simply run “easy_install betterprint”, or visit the web page for more details and installation instructions.

Python Call Graph 0.4.0

I’ve just released pycallgraph 0.4.0. It has several major new features including a command line interface and measuring accumulative time per function.

The 0.4.0 pycallgraph CLI supports function filtering, timing filtering, maximum stack level and a few more settings. For example, to do a simple call graph on “myfile.py”:

pycallgraph-dot.py myfile.py mygraph.png

Here’s an example that doesn’t include the class Foo and outputs to a SVG file format:

pycallgraph-dot.py –exclude=”*.Foo.*” –image-format=svg myfile.py myfile.svg

Turns out far easier than modifying your source code to create a call graph.

Here’s one of the graphs from the source code examples colours.py:

Orange Green Example

As you can see it has green and orange gradients. One end of the gradient is green because of the number of calls is high and the other is orange because the function calls are taking the longest. All that with a function that looks like this:

def orange_green(calls, total_time):
    """Make a higher total time have an orange colour and a higher number
    of calls have a green colour using RGB.
    """
    return '#%02X%02X%02X' % (
        0x30 + total_time * 0xc0,
        0x30 + calls * 0xc0 + total_time * 0x70,
        0x30,
    )

I hope it’s useful to you!