Question2Answer Coding Style guidelines

From 1.7 onwards a new coding style is being implemented that is more in line with other projects. The core codebase is gradually being refactored, and any new code should use the guidelines below. When making changes it’s encouraged to update the style of the surrounding code, e.g. the rest of the function being modified.

However, please keep style-only changes to a separate commit! For example if you fix a bug, do that first in one commit, then optionally reformat the rest of the function’s code and perform a second commit.

Guidelines

  • PHP code should start with <?php (almost always the very first line). The closing tag ?> should be omitted to avoid accidental output.
  • PHP files should use UTF-8 encoding without BOM (this is usually default in most text editors).
  • Trailing whitespace (tabs or spaces at the end of lines) should be trimmed on save. Any advanced text editor should be able to do this. (For Sublime Text you can add the option "trim_trailing_white_space_on_save": true to your preferences. In Notepad++ you can press Alt+Shift+S.)
  • Use tabs for indenting. Each file should start at level 0 (i.e. no indentation).
  • Functions should use a DocBlock-style comment.
  • Operators (=, + etc) should have a space either side.
  • Control structure keywords (if, else, foreach etc) should have a space between them and the opening parenthesis.
  • Opening braces for classes and functions should be on the next line.
  • Opening braces for control structures should be on the same line. All control structures should use braces.

Examples

Here is an example of the old style. Even though the braces are technically optional (the foreach contains only one statement), they should be used here for clarity.

foreach ($thingarray as $thing)
    if (isset($thing['id']))
        if (strpos($thing['id'], 'Hello')===0)
            $newthing='Goodbye';
        elseif ($thing['id']=='World')
            $newthing='Galaxy';

It should be rewritten as:

foreach ($thingarray as $thing) {
    if (isset($thing['id'])) {
        if (strpos($thing['id'], 'Hello') === 0) {
            $newthing = 'Goodbye';
        } elseif ($thing['id'] == 'World') {
            $newthing = 'Galaxy';
        }
    } else {
        return null;
    }
}

Here is a class example showing the placement of braces, operators, and a DocBlock comment.

class qa_example
{
    /**
     * Adds 1 to the supplied number.
     *
     * @param int $number The number to increment.
     * @return int Returns the new number.
     */
    public function add_one($number)
    {
        $result = $number + 1;

        return $result;
    }
}

New autoloaded classes

From version 1.7 some classes are autoloaded, so it’s possible to use them without adding a require_once first. These loosely follow PSR-0 using faux namespaces. This is being done slowly and carefully to maintain backwards compatibility, and does not apply to plugins, themes, nor most of the core for that matter.

Classes are stored in the qa-include/Q2A folder, and then in subfolders depending on their categorization.

Class names should be of the form Q2A_<Namespace>_<Class>, e.g. Q2A_Util_Debug. There may be multiple “namespaces”, e.g. Q2A_Db_User_Messages.

Classes are mapped to PHP files with the underscores converted to directory separators. The Q2A_Util_Debug class is in the file qa-include/Q2A/Util/Debug.php. A class named Q2A_Db_User_Messages would be in a file qa-include/Q2A/Db/User/Messages.php.