Refactoring (notes)

Make it work, make it right, make it fast
– Kent Beck (attributed)

Test, Change, Test again

The Zen of Python, by Tim Peters:

import this

Write code that's

• easy to read
• easy to modify
• regular
• short
• fast

Think of every line of code as a message for someone in the future.
– Linda Rising

When you look at source code, the meaning of the program should be apparent. [...] If your code needs comments, consider refactoring it so it doesn’t.
– Peter Sommerlad

Style

• Set of techniques for programming leading to a consistent use of language features
• Sometimes used in a very restricted sense to refer just to low-level rules for naming and appearance of code (coding standard)

Coding Standard

• A set of rules for what code should look like
• Common aims are to improve reliability, portability, maintainability, testability, reusability, extensibility and readability
• All coding standards are disliked by programmers, even the good ones.
  – Bjarne Stroutrup
• To avoid code that is poorly written (using programming language facilities in unnecessarily error-prone ways or expressing ideas in ways that obscure their meaning)
• Coding standards are trying to address incidental complexities rather than inherent complexities; sources for these are
  • overly clever programmers
  • undereducated programmers (not using the most appropriate language and library features)
  • unnecessary variations in programming style
  • inappropriate programming language
• A coding standard should
  • help a programmer write good code
  • by giving answers to lots of little questions
  • not be annoying/ pointless/ solely a list of don'ts
  • be designed for a specific application domain and a specific group of programmers
  • be prescriptive as well as restrictive

• http://www.python.org/dev/peps/pep-0008/
• http://stackoverflow.com/questions/356161/python-coding-standards-best-practices
• http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml

Use tools to facilitate processes, but don't let the tools become ends in themselves.

Tools

pep8

A tool to check your Python code against some of the style conventions in PEP 8.

pyflakes

simple Python source checker

pylint

python code static checker

...

cppcheck

Tool for static C/C++ code analysis (in repositories)

cpplint.py

Lint for Google's C++ coding style

...

Examples

• refactor old homework or the term project (speed, elegance, ...)
• open files with explicit encoding