PyObjCTools.NibClassBuilder – Magic NIBs

Deprecated since version 2.4: Use of this module is deprecated because it cannot be used with modern versions of Xcode (starting at Xcode 4.0), and because recent versions of Xcode can extract class information from Python sources.


The module is used to avoid repeating class inheritance and outlet definitions in both python sources and Interface Builder NIB files.

The module reads this information from NIB files and provides a magic meta class that inserts the right superclass and outlet definitions.

Do not use this module for new developement, it will likely disappear in a future version of PyObjC because it can no longer work with modern versions of Xcode, and in particular not with XIB files and compiled NIB files.

Extracting class definitions from nibs

The module maintains a global set of class definitions, extracted from nibs. To add the classes from a nib to this set, use the extractClasses() function. It can be called in two ways:

PyObjCTools.NibClassBuilder.extractClasses(nibName, bundle=<current-bundle>)

This finds the nib by name from a bundle. If no bundle if given, the objc.currentBundle() is searched.


This uses an explicit path to a nib.

extractClasses() can be called multiple times for the same bundle: the results are cached so no almost extra overhead is caused.

Using the class definitions

The module contains a “magic” base (super) class called AutoBaseClass. Subclassing AutoBaseClass will invoke some magic that will look up the proper base class in the class definitions extracted from the nib(s). If you use multiple inheritance to use Cocoa’s “informal protocols”, you must list AutoBaseClass as the first base class. For example:

class PyModel(AutoBaseClass, NSTableSource):

The NibInfo class

The parsing of nibs and collecting the class definition is done by the NibInfo class. You normally don’t use it directly, but it’s here if you have special needs.

The command line tool

When run from the command line, this module invokes a simple command line program, which you feed paths to nibs. This will print a Python template for all classes defined in the nib(s). For more documentation, see the commandline_doc variable, or simply run the program without arguments. It also contains a simple test program.