When contributing code to IPython, you should strive for clarity and consistency, without falling prey to a style straitjacket. Basically, ‘document everything, try to be consistent, do what makes sense.’
By and large we follow existing Python practices in major projects like Python itself or NumPy, this document provides some additional detail for IPython.
All standalone documentation should be written in plain text (.txt) files using reStructuredText [reStructuredText] for markup and formatting. All such documentation should be placed in the directory docs/source of the IPython source tree. Or, when appropriate, a suitably named subdirectory should be used. The documentation in this location will serve as the main source for IPython documentation.
The actual HTML and PDF docs are built using the Sphinx [Sphinx] documentation generation tool. Once you have Sphinx installed, you can build the html docs yourself by doing:
$ cd ipython-mybranch/docs $ make html
Our usage of Sphinx follows that of matplotlib [Matplotlib] closely. We are using a number of Sphinx tools and extensions written by the matplotlib team and will mostly follow their conventions, which are nicely spelled out in their documentation guide [MatplotlibDocGuide]. What follows is thus a abridged version of the matplotlib documentation guide, taken with permission from the matplotlib team.
If you are reading this in a web browser, you can click on the “Show Source” link to see the original reStricturedText for the following examples.
A bit of Python code:
for i in range(10): print i, print "A big number:",2**34
An interactive Python session:
>>> from IPython.utils.path import get_ipython_dir >>> get_ipython_dir() '/home/fperez/.config/ipython'
An IPython session:
In : import IPython In : print "This IPython is version:",IPython.__version__ This IPython is version: 0.9.1 In : 2+4 Out: 6
A bit of shell code:
cd /tmp echo "My home directory is: $HOME" ls
Good docstrings are very important. Unfortunately, Python itself only provides a rather loose standard for docstrings [PEP257], and there is no universally accepted convention for all the different parts of a complete docstring. However, the NumPy project has established a very reasonable standard, and has developed some tools to support the smooth inclusion of such docstrings in Sphinx-generated manuals. Rather than inventing yet another pseudo-standard, IPython will be henceforth documented using the NumPy conventions; we carry copies of some of the NumPy support tools to remain self-contained, but share back upstream with NumPy any improvements or fixes we may make to the tools.
For user-facing APIs, we try to be fairly strict about following the above standards (even though they mean more verbose and detailed docstrings). Wherever you can reasonably expect people to do introspection with:
In : some_function?
the docstring should follow the NumPy style and be fairly detailed.
For purely internal methods that are only likely to be read by others extending IPython itself we are a bit more relaxed, especially for small/short methods and functions whose intent is reasonably obvious. We still expect docstrings to be written, but they can be simpler. For very short functions with a single-line docstring you can use something like:
def add(a, b): """The sum of two numbers. """ code
and for longer multiline strings:
def add(a, b): """The sum of two numbers. Here is the rest of the docs. """ code
Here are two additional PEPs of interest regarding documentation of code. While both of these were rejected, the ideas therein form much of the basis of docutils (the machinery to process reStructuredText):
In the past IPython used epydoc so currently many docstrings still use epydoc conventions. We will update them as we go, but all new code should be documented using the NumPy standard.
The built docs are stored in a separate repository. Through some github magic, they’re automatically exposed as a website. It works like this:
|[PEP257]||PEP 257. http://www.python.org/peps/pep-0257.html|
|[NumPyDocGuide]||NumPy documentation guide. http://projects.scipy.org/numpy/wiki/CodingStyleGuidelines|
|[NumPyExampleDocstring]||NumPy example docstring. http://projects.scipy.org/numpy/browser/trunk/doc/EXAMPLE_DOCSTRING.txt|