Perhaps the most important part of the PEAR project is finally defining an official standard for creating reusable, well documented php packages. A standard set of guidelines are necessary to make sure all PEAR packages are available to as many developers as possible. Since PEAR is still in development, the current set of rules and guidelines are subject to discussion and change. If you take issue with any of these guidelines, or have a better solution, you should let the developers know by posting to the PHP-PEAR mailing list.

The extension .php must be used for all files containing php code. A related set of one or more classes and functions are called a "package". These packages are organized into the PEAR package structure. The package structure maps 1:1 to the file system, but is based on the argument provided to the "use" or "import" functions.

Because PHP does not implement name-spaces, class names must be based on the package they are implemented in. The class name is derived by simply replacing the slashes in the package name with under scores. Thus, the package "DB/common" has it's code in the file "DB/common.php", and defines a class called "DB_common". This strategy should prevent any naming collisions despite the lack of separate name-spaces.

Functions should be named with underscores separating lowercase words, for example my_function. Methods should use initial lowercase studly caps, like myMethod.