Overview
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# Overview

Writing a Baul-Python extension is a fairly straight-forward process. One simply imports the Baul module from the gobject introspection repository and creates a class which is derived from a gobject.GObject and one of the Baul module's classes. When an extension derives a class, it becomes a "provider", telling Baul to ask it for information. There are several types of providers available for extensions to use: there is MenuProvider, LocationWidgetProvider, ColumnProvider, PropertyPageProvider, and InfoProvider, all of which will be explained in more detail below. Your class can be derived from multiple providers.

Here are the basic steps:

1. A script is written and installed to the standard baul-python extension install path

2. Baul is (re)started and loads the baul-python C extension, which in turn loads all python extensions it can find

3. Any python script in the standard baul-python extension install path that imports the Baul module from the gobject introspection repository and derives the main class from a Baul module class will be loaded

### A note about the standard python extensions install path

As of baul-python 0.7.0 (and continued in 1.0+), baul-python looks in ~/.local/share/baul-python/extensions for local extensions and $PREFIX/share/baul-python/extensions for global extensions.

### A note about compatibility issues for baul-python 1.0

1. We no longer support the "import baul" command that previous versions used. This is because baul-python now directly uses Baul's annotations, which must be imported by the "from gi.repository import Baul" command.

2. The extension class must now derive itself from a gobject.GObject in addition to the standard Baul classes.

3. For now, some Baul class constructors require passing named arguments instead of a standard argument list. This requirement may go away at some point.

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