py2annotate 1.0.0

An extension to Sphinx `autodoc` to augment sphinx documentation with type annotations, when using Python 2 style type annotations.

An extension to Sphinx autodoc to augment sphinx documentation with type annotations, when using Python 2 style type annotations.

The Problem

Python 2 doesn’t support type annotations. Thus writing Python 2 / Python 3 agnostic code with type annotations requires putting the type annotations in comments:

def add(x, y):
    # type: (int, int) -> int
    """Adds two numbers."""
    return x + y

But now when documentation is generated with sphinx, the documentation doesn’t include type annotations:

Example from the Signatory project.

The Solution

This extension remedies things so that the Sphinx documentation now looks like:

(which is the same as what you’d get using Python 3 style type annotations e.g. def add(x: int, y: int) -> int)

Installation

Via pip:

pip install py2annotate

It’s also just a single file, so copy-paste the code if you want.

Usage

Just add py2annotate to the list of extensions in conf.py:

# conf.py
...
extensions = ['sphinx.ext.autodoc', 'py2annotate']
...

(It shouldn’t actually matter whether it comes before or after autodoc.)

Note that Sphinx itself must be run using Python 3, not Python 2. This is because py2annotate uses the Python 3 style type annotations internally in order to determine the correct annotations.

Known Issues

None so far! File a report if you run into anything.