PyObjC

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 macOS applications in pure Python.

There is also limited support for GNUstep, an open source, cross-platform implementation of Cocoa.

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 to 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.

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.

PyObjC's origins date back to 1996, when Lele Gaifax built the original module in September of that year. Among the credited contributors were Guido van Rossum, creator of the Python programming language.

PyObjC was rewritten in 2002. Notable additions include the ability to directly subclass Objective-C classes from Python and nearly complete support for the Foundation, App Kit and Address Book frameworks.

Later the same year, support was added for non-framework Python builds, as well as subsequent support for the Python distribution included with Mac OS X. Along with these changes came project templates for standalone Cocoa applications for use with Project Builder, the predecessor to the current Apple platform IDE, Xcode.