PyObjC
| Developer(s) | Ronald Oussoren, Bill Bumgarner, Steve Majewski, Lele Gaifax, et al. |
|---|---|
| Stable release | 2.3.2a (as part of OS X 10.8)
/ July 25, 2012 |
| Repository | |
| Written in | Python |
| Operating system | Cross-platform |
| License | MIT License |
| Website | http://pyobjc.sourceforge.net/ |
PyObjC is a bidirectional bridge between the Python and Objective-C programming languages, allowing programmers to use and extend existing Objective-C libraries, such as Apple's Cocoa framework, using Python.
PyObjC is used to develop OS X applications in pure Python.
There is also limited support for GNUstep, an open source, cross-platform implementation of Cocoa.
For Python Programmers
The most important usage of PyObjC is enabling programmers to create GUI applications using Cocoa libraries in pure Python. Moreover, as an effect of Objective-C's close relationship with the C programming language (it is a pure superset), developers are also able incorporate any C-based API by wrapping it with an Objective-C wrapper and then using the wrapped code over the PyObjC bridge. Using Objective-C++, the same can be done with C++ libraries.
For Objective-C Programmers
Cocoa developers may also benefit, as tasks written in Python generally take fewer lines than the Objective-C equivalent. This can be used to their advantage as it enables faster prototyping.
History and Contributors
The history of PyObjC before 2000 is quite fuzzy and here are some parts referenced from different sites:
The “objc” module has been found as part of the 1.3 release of Python (released in 1995), claimed to be written by Jon M. Kutemeier and maintained by Guido van Rossum. But later been removed from core since the 1.4 release.
Lele Gaifax built the original module of PyObjC in September 1996. And Lele’s contributors list can be found in official website here.
Steve Majewski and Bill Bumgarner started to handle this work since 2000. And since PyObjC is maintain and developed by Ronald Oussoren, Bill Bumgarner, Just van Rossum, and Jack Jansen.
Apple started to support PyObjC since Mac OS X 10.4 Tiger, and PyObjC 2.0 was shipped as component of Mac OS X 10.5 Leopard by Apple.
As to the integrated development environment support, Xcode 2.5 provided templates and is fully supported with PyObjC. Templates had been removed since Xcode 3.0, but Xcode 3.0 is still providing support to Python, therefore the Interface Builder, which is shipped with Xcode 3.0, understands Python scripts and syntax. According to Ronald Oussoren, Interface Builder since Xcode 4.0 is no longer compatible with PyObjC anymore.
Principle Behind Bridge
The implementation of bridging between Python and Objective-C is by BridgeSupport and libffi. The core concept of connection is based on that Objective-C uses messages for communication between its objects. And PyObjC provides translation from these messages to Python methods by replacing the colons with underscores. Following is the sample for translation.
Messages and Methods
For the syntax conversion, simply change the colons from original Objective-C code to underscores. Such like following examples:
[myLittleDuck makeSomeNoise:quack]
the above code should be changed like following
myLittleDuck.makeSomeNoise_(quack)
And for more than one parameter messages, one can follow the same principle:
[myLittleDuck flyToward:east flyWithSpeed:10]
should be converted as:
myLittleDuck.flyToward_flyWithSpeed_(east,10)
Classes
The classes of Objective-C could be simply subclassed like normal Python classes. following can be referenced as example of class initiation:
class MyDuck(NSObject):
def init(self):
self = super(MyDuck, self).init()
#ALWAYS call initializer from super class
return self
#Unlike Python, one can even return any other object in initializer.
MyLittleDuckOne = MyDuck.alloc().init()
External links
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