Coding standard

> _This document is a work in progress and might be incomplete._ General ------- * Use spaces, not tabs. * Avoid adding trailing whitespace as it creates noise in the diffs. Python ------ * Comments should not exceed 80 columns, code should not exceed 120 columns. * All code must be compatible with Python 2.7, 3.5, and 3.6. * [Pylint][pylintlink] should not give any error or warning (few exceptions apply with external classes like `numpy`, see our `.pylintrc`). * Python code follows [PEP8 style guide][pep8link] (use `autopep8` whenever possible). [pylintlink]: https://www.pylint.org/ [pep8link]: https://www.python.org/dev/peps/pep-0008/ C++ --- * Comments should not exceed 80 columns, code may exceed this limit a bit in rare occasions if it results in clearer code. * Compilation should not give any error or warning (`clang++-6.0 -Wall -Wextra -std=C++14 -Wno-missing-braces`). * The use of `throw` is forbidden, use `carla::throw_exception` instead. * Unreal C++ code (CarlaUE4 and Carla plugin) follow the [Unreal Engine's Coding Standard][ue4link] with the exception of using spaces instead of tabs. * LibCarla uses a variation of [Google's style guide][googlelink]. * Uses of `try-catch` blocks should be surrounded by `#ifndef LIBCARLA_NO_EXCEPTIONS` if the code is used in the server-side. [ue4link]: https://docs.unrealengine.com/latest/INT/Programming/Development/CodingStandard/ [googlelink]: https://google.github.io/styleguide/cppguide.html