1. Ronald Oussoren
  2. pyobjc


pyobjc / pyobjc-core / Doc / dev / coding-style.rst

Coding style for PyObjC


This document describes the coding style for PyObjC. Please use this style for new code and try apply this style to existing code while working on it.

The management summary: 4-space indents in Python code, 1-TAB indents in C code.

Python code

The coding style for core Python is used (see PEP 8). For consistency with Cocoa we use mixed-case identifiers (like lookUpClass).

PyObjC extensions to Apple frameworks should be clearly marked as such, preferably by prefixing names with PyObjC or pyobjc. This should make it clear to users where they should look for documentation of an item: The Apple documentation or ours.

C code

The coding style for core Python is used (see PEP 7). We use PyObjC instead of Py as the prefix for globally visible symbols.

All (Objective-)C files in Modules/objc/ should include "pyobjc.h" as their first include. The (Objective-)C files in the wrappers for frameworks should include "pyobjc-api.h" and should not use other headers files from pyobjc-core.

The setup.py for a framework wrapper should defer most work to pyobjc_setup.py, like so:

from pyobjc_setup import setup

   description = "Wrappers for the framework AddressBook on Mac OS X",
   packages = [ "AddressBook" ],
   install_requires = [

The framework wrappers do not include a copy of pyobjc-api.h, but dynamicly fetch that at build time.


All items exported by the objc module and all PyObjC extensions to Apple frameworks (the AppKit and Foundation modules) should be documented using docstrings.

All documentation-- both standalone documents and docstrings-- should be marked up using reStructuredText [ReST].

ReST in DocStrings

reStructuredText can be used in doc strings. ReST in DocStrings works exactly like a standalone ReST document, but the ReST is broken up slightly differently.

To format the DocStrings to be ReST compatible, make the following changes/additions to the source. These examples were taken from source found in the DocUtils source tree.

  1. Add appropriate ReST style fields to the top of the document as comments:

    # Author: David Goodger
    # Contact: goodger@users.sourceforge.net
    # Copyright: This module has been placed in the public domain.
  2. Add a module level variable that indicates that ReST is used to format the text contained in the docstrings:

    __docformat__ = 'reStructuredText'
  3. Format all other DocStrings as one normally would in Python. Use ReST style markup where appropriate. For example, bulleted lists and sections might commonly appear in the module or class docstrings. The docstrings for individual methods may use example blocks, hyperlinks, or any other ReST markup.