PyOGP Coding Guidelines
Note: New page, and pyogp is not conforming to the guidelines as of writing. Enus Linden 18:23, 22 July 2009 (UTC)
Begin all Python source code files with this header:
<python> """ @file filename @brief brief description Contributors: http://svn.secondlife.com/svn/linden/projects/2008/pyogp/CONTRIBUTORS.txt
Copyright (c) 2009, Linden Research, Inc.
Licensed under the Apache License, Version 2.0 (the "License"). You may obtain a copy of the License at:
$/LicenseInfo$ """ </python>
Generally based on http://www.python.org/dev/peps/pep-0008/, with specific details called out below.
One line requirements:
- line length should be 80 characters if possible, do not exceed 150 (?)
- a single blank line separates class methods/functions
- a blank line == ^$ (no unnecessary spaces)
- multiple statements on a single line is discouraged
Summarized from http://www.python.org/dev/peps/pep-0008/.
- packages and modules: short lowercase, underscores acceptable if required
- classes: CapWords (aka CamelCase)
- exceptions: CapWords, with a suffix of "Error"
- global variables: let's not have these
- functions: lowercase, underscores acceptable if required
- function and method arguments: lowercase, underscores acceptable if required
- in the case of reserved keyword collision, append a trailing underscore to the argument (id_).
- method names and variables: lowercase, underscores acceptable if required
- one leading underscore of non-public methods and variables
Comments should describe why this code is as it is, rather than what it's doing.
Block comments start with a # and are followed by a space.
Inline comments should be sparsely used.
If leaving a item to address in the future, or a question, prepend the comment string with "# ToDo: ".
Conform to the pythonic standard when dealing with whitespace:
- one space is expected after a comma, semicolon, colon, around binary operators ( = ), arithmetic operators
- no spaces expected when dealing with keyword arguments or parameter values (def function(arg1, arg2=True))
4 spaces is our standard indentation. Please do not mix in tabs. Really.
Put this in your ~/.emacs to get the desired behavior (note that this also turns on colored fonts, which you probably wanted anyway):
(defun ll-python-mode-hook() (font-lock-mode 1) (font-lock-fontify-buffer) (set-variable 'indent-tabs-mode nil) (set-variable 'py-indent-offset 4) (message "ll coding style function executed")) (add-hook 'python-mode-hook 'll-python-mode-hook)
(insert instructions on using python-mode if it's not with your default emacs install)
To convert tabs to spaces in Emacs:
- Make sure your tab width is 4
- In .emacs
(set-variable 'tab-width 4)(optionally inside your ll-python-mode-hook())
- Immediately: M-x set-variable[ret] tab-width[ret] 4[ret]
- In .emacs
- Set mark at start of file: M-< ^space
- Jump to end of file: M->
- Convert tabs to spaces within marked range: M-x untabify
To use spaces instead of tabs in vi put this in ~/.vimrc:
set tabstop=4 set shiftwidth=4 # When reading a file or creating a new file, uses spaces not tabs autocmd BufRead,BufNewFile *.py set expandtab
Another option for tabs/spaces:
# automatically expand tab keypresses into the appropriate number of spaces set expandtab
- Include only one module per line
- Order your imports alphabetically (this gets a little vague with "from x in y" imports TODO: invent a rule that makes sense)
- Try not to pollute the module's namespace by importing individual functions and classes from other modules.
- Do not use 'import *'
<python> from os.path import join, dirname, realpath from pyogp.lib.base import agent, region from pyogp.lib.base.datatypes import * </python>
<python> import os.path import socket import urllib2 from pyogp.lib.base.agent import Agent from pyogp.lib.base.region import Region from pyogp.lib.base.datatypes import UUID, Vector3 </python>
Pylint can analyze a package or module for conformity to standard pythonic coding guidelines. Use this to review your code prior to checkin.
- ToDo: Enus to provide a standard pylint command...
Enus on his Macbook Pro with pylint 0.18.0:
easy_install pylint export PYOGPPATH="'/Users/enus/svn/pyogp/trunk/src/pyogp.lib.base/pyogp/'" (replace with path to your dependencies) export PYOGPDEPS="'/Users/enus/svn/pyogp/trunk/eggs/'" (replace with path to your dependencies) pylint --max-line-length=200 --disable-msg=E1101,C0103,R0913 --init-hook="import sys; sys.path.append($PYOGPPATH); [sys.path.append(os.path.join($PYOGPDEPS, package)) for package in os.listdir($PYOGPDEPS) if not package == '.svn' and not package == 'EXTERNALS.txt']" src/pyogp.lib.base/pyogp/lib/base/region.py
Docstrings are required for all modules, classes, methods and functions,
The standard here is pulled from http://www.python.org/dev/peps/pep-0257/, which is our guideline.
- Use triple double quotes for docstring: """this is a docstring""".
- The text should describe the functionality of the function or method, and should only describe the parameters and return values when it is not clear.
- Use one line docstrings when possible.
- When using a multiline docstring, the first line should be the description, followed by a blank line, followed by details in subsequent lines.
- Docstrings should observe the line length limit (see above)
Unit test coverage should come to be expected for each checkin.