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To facilitate quality third-party add-ons, EllisLab has defined the following programming guidelines. Even if you do not plan on publicly releasing your add-on, you will greatly benefit from the security, performance tips, and uniformity of code that results from following these guidelines.
Some things may be different from your current coding style, but it is important to remember that you rarely will be the only person working with the code. Consistency makes it easier for other developers to follow. And memories fade, so that “other developer” may simply be you, six months later!
After reading and understanding the above sections, you can use the Summarized Checklist to assist you in reviewing your code prior to submission.