Code style

All code in fresnel must follow a consistent style to ensure readability. We provide configuration files for linters (specified below) so that developers can automatically validate and format files.

Python

Python code in fresnel should follow PEP8 with the following choices:

• 80 character line widths.

• Hang closing brackets.

• Break before binary operators.

Tools

• Linter: flake8 with pep8-naming

• Autoformatter: autopep8

• Run: flake8 to see a list of violations.

• See setup.cfg for the flake8 configuration (also used by autopep8).

Documentation

Python code should be documented with docstrings and added to the Sphinx documentation index in doc/. Docstrings should follow Google style formatting for use in Napoleon.

C++/CUDA

• 100 character line width.

• Indent only with spaces.

• 4 spaces per indent level.

• Naming conventions:

  • Namespaces: All lowercase somenamespace

  • Class names: UpperCamelCase

  • Methods: lowerCamelCase

  • Member variables: m_ prefix followed by lowercase with words separated by underscores m_member_variable

  • Constants: all upper-case with words separated by underscores SOME_CONSTANT

  • Functions: lowerCamelCase

Tools

• Autoformatter: clang-format.

• Run: ./run-clang-format.py -r fresnel to see needed changes.

• Run: clang-format -i file.cc to apply the changes to a specific file.

• Style configuration: See .clang-format.

Note

We plan to provide change the style once clang-format 10 is available.

Documentation

Documentation comments should be in Javadoc format and precede the item they document for compatibility with Doxygen and most source code editors. Multi-line documentation comment blocks start with /** and single line ones start with ///.

Other file types

Use your best judgment and follow existing patterns when styling CMake, restructured text, markdown, and other files. The following general guidelines apply:

• 100 character line width.

• 4 spaces per indent level.

• 4 space indent.