Merge pull request #150 from mobify/python-docstring-format

Python docstring format recommendation

Author: benlast

python/README.md

@@ -148,3 +148,14 @@ Message codes can be found [here](http://pylint-messages.wikidot.com/all-codes).
 Disable works for the block in which they are found, so include it at the module
 level to disable a message for a module or file.
 
+## Docstrings
+
+We don't have a company-wide standard for Docstrings, but if you're
+starting a new project, a good choice is the [Google style](https://google.github.io/styleguide/pyguide.html#Comments).
+The official Google documentation isn't always easy to follow, but there
+is an example file in [`example_google.py`](./example_google.py), in this repository.
+
+Using correct `Args` and `Returns` descriptions in your code will make it
+easier for you (or others) to work with many IDEs and code-aware editors
+that can infer the types of parameters and return values for you.
+

python/example_google.py

@@ -0,0 +1,297 @@
+# -*- coding: utf-8 -*-
+"""Example Google style docstrings.
+
+This module demonstrates documentation as specified by the `Google Python
+Style Guide`_. Docstrings may extend over multiple lines. Sections are created
+with a section header and a colon followed by a block of indented text.
+
+Example:
+    Examples can be given using either the ``Example`` or ``Examples``
+    sections. Sections support any reStructuredText formatting, including
+    literal blocks::
+
+        $ python example_google.py
+
+Section breaks are created by resuming unindented text. Section breaks
+are also implicitly created anytime a new section starts.
+
+Attributes:
+    module_level_variable1 (int): Module level variables may be documented in
+        either the ``Attributes`` section of the module docstring, or in an
+        inline docstring immediately following the variable.
+
+        Either form is acceptable, but the two should not be mixed. Choose
+        one convention to document module level variables and be consistent
+        with it.
+
+Todo:
+    * For module TODOs
+    * You have to also use ``sphinx.ext.todo`` extension
+
+.. _Google Python Style Guide:
+   http://google.github.io/styleguide/pyguide.html
+
+"""
+
+module_level_variable1 = 12345
+
+module_level_variable2 = 98765
+"""int: Module level variable documented inline.
+
+The docstring may span multiple lines. The type may optionally be specified
+on the first line, separated by a colon.
+"""
+
+
+def function_with_types_in_docstring(param1, param2):
+    """Example function with types documented in the docstring.
+
+    `PEP 484`_ type annotations are supported. If attribute, parameter, and
+    return types are annotated according to `PEP 484`_, they do not need to be
+    included in the docstring:
+
+    Args:
+        param1 (int): The first parameter.
+        param2 (str): The second parameter.
+
+    Returns:
+        bool: The return value. True for success, False otherwise.
+
+    .. _PEP 484:
+        https://www.python.org/dev/peps/pep-0484/
+
+    """
+
+
+def function_with_pep484_type_annotations(param1: int, param2: str) -> bool:
+    """Example function with PEP 484 type annotations.
+
+    Args:
+        param1: The first parameter.
+        param2: The second parameter.
+
+    Returns:
+        The return value. True for success, False otherwise.
+
+    """
+
+
+def module_level_function(param1, param2=None, *args, **kwargs):
+    """This is an example of a module level function.
+
+    Function parameters should be documented in the ``Args`` section. The name
+    of each parameter is required. The type and description of each parameter
+    is optional, but should be included if not obvious.
+
+    If \*args or \*\*kwargs are accepted,
+    they should be listed as ``*args`` and ``**kwargs``.
+
+    The format for a parameter is::
+
+        name (type): description
+            The description may span multiple lines. Following
+            lines should be indented. The "(type)" is optional.
+
+            Multiple paragraphs are supported in parameter
+            descriptions.
+
+    Args:
+        param1 (int): The first parameter.
+        param2 (:obj:`str`, optional): The second parameter. Defaults to None.
+            Second line of description should be indented.
+        *args: Variable length argument list.
+        **kwargs: Arbitrary keyword arguments.
+
+    Returns:
+        bool: True if successful, False otherwise.
+
+        The return type is optional and may be specified at the beginning of
+        the ``Returns`` section followed by a colon.
+
+        The ``Returns`` section may span multiple lines and paragraphs.
+        Following lines should be indented to match the first line.
+
+        The ``Returns`` section supports any reStructuredText formatting,
+        including literal blocks::
+
+            {
+                'param1': param1,
+                'param2': param2
+            }
+
+    Raises:
+        AttributeError: The ``Raises`` section is a list of all exceptions
+            that are relevant to the interface.
+        ValueError: If `param2` is equal to `param1`.
+
+    """
+    if param1 == param2:
+        raise ValueError('param1 may not be equal to param2')
+    return True
+
+
+def example_generator(n):
+    """Generators have a ``Yields`` section instead of a ``Returns`` section.
+
+    Args:
+        n (int): The upper limit of the range to generate, from 0 to `n` - 1.
+
+    Yields:
+        int: The next number in the range of 0 to `n` - 1.
+
+    Examples:
+        Examples should be written in doctest format, and should illustrate how
+        to use the function.
+
+        >>> print([i for i in example_generator(4)])
+        [0, 1, 2, 3]
+
+    """
+    for i in range(n):
+        yield i
+
+
+class ExampleError(Exception):
+    """Exceptions are documented in the same way as classes.
+
+    The __init__ method may be documented in either the class level
+    docstring, or as a docstring on the __init__ method itself.
+
+    Either form is acceptable, but the two should not be mixed. Choose one
+    convention to document the __init__ method and be consistent with it.
+
+    Note:
+        Do not include the `self` parameter in the ``Args`` section.
+
+    Args:
+        msg (str): Human readable string describing the exception.
+        code (:obj:`int`, optional): Error code.
+
+    Attributes:
+        msg (str): Human readable string describing the exception.
+        code (int): Exception error code.
+
+    """
+
+    def __init__(self, msg, code):
+        self.msg = msg
+        self.code = code
+
+
+class ExampleClass(object):
+    """The summary line for a class docstring should fit on one line.
+
+    If the class has public attributes, they may be documented here
+    in an ``Attributes`` section and follow the same formatting as a
+    function's ``Args`` section. Alternatively, attributes may be documented
+    inline with the attribute's declaration (see __init__ method below).
+
+    Properties created with the ``@property`` decorator should be documented
+    in the property's getter method.
+
+    Attributes:
+        attr1 (str): Description of `attr1`.
+        attr2 (:obj:`int`, optional): Description of `attr2`.
+
+    """
+
+    def __init__(self, param1, param2, param3):
+        """Example of docstring on the __init__ method.
+
+        The __init__ method may be documented in either the class level
+        docstring, or as a docstring on the __init__ method itself.
+
+        Either form is acceptable, but the two should not be mixed. Choose one
+        convention to document the __init__ method and be consistent with it.
+
+        Note:
+            Do not include the `self` parameter in the ``Args`` section.
+
+        Args:
+            param1 (str): Description of `param1`.
+            param2 (:obj:`int`, optional): Description of `param2`. Multiple
+                lines are supported.
+            param3 (:obj:`list` of :obj:`str`): Description of `param3`.
+
+        """
+        self.attr1 = param1
+        self.attr2 = param2
+        self.attr3 = param3  #: Doc comment *inline* with attribute
+
+        #: list of str: Doc comment *before* attribute, with type specified
+        self.attr4 = ['attr4']
+
+        self.attr5 = None
+        """str: Docstring *after* attribute, with type specified."""
+
+    @property
+    def readonly_property(self):
+        """str: Properties should be documented in their getter method."""
+        return 'readonly_property'
+
+    @property
+    def readwrite_property(self):
+        """:obj:`list` of :obj:`str`: Properties with both a getter and setter
+        should only be documented in their getter method.
+
+        If the setter method contains notable behavior, it should be
+        mentioned here.
+        """
+        return ['readwrite_property']
+
+    @readwrite_property.setter
+    def readwrite_property(self, value):
+        value
+
+    def example_method(self, param1, param2):
+        """Class methods are similar to regular functions.
+
+        Note:
+            Do not include the `self` parameter in the ``Args`` section.
+
+        Args:
+            param1: The first parameter.
+            param2: The second parameter.
+
+        Returns:
+            True if successful, False otherwise.
+
+        """
+        return True
+
+    def __special__(self):
+        """By default special members with docstrings are not included.
+
+        Special members are any methods or attributes that start with and
+        end with a double underscore. Any special member with a docstring
+        will be included in the output, if
+        ``napoleon_include_special_with_doc`` is set to True.
+
+        This behavior can be enabled by changing the following setting in
+        Sphinx's conf.py::
+
+            napoleon_include_special_with_doc = True
+
+        """
+        pass
+
+    def __special_without_docstring__(self):
+        pass
+
+    def _private(self):
+        """By default private members are not included.
+
+        Private members are any methods or attributes that start with an
+        underscore and are *not* special. By default they are not included
+        in the output.
+
+        This behavior can be changed such that private members *are* included
+        by changing the following setting in Sphinx's conf.py::
+
+            napoleon_include_private_with_doc = True
+
+        """
+        pass
+
+    def _private_without_docstring(self):
+        pass