Why Adopt a Personal PHP Coding Standard? Boost Efficiency and Readability

Why develop your own coding standards?

Establishing a personal coding standard brings several unexpected benefits: it improves coding efficiency, enhances readability, showcases professionalism, and facilitates team collaboration.

Code Writing Conventions

Folder naming: use all lowercase letters, e.g., controller for a controllers folder.

File naming: class files follow PascalCase (big camel) and end with .class.php (e.g., Session.class.php); utility scripts use camelCase (small camel) like common.php.

Class naming: PascalCase, e.g., Cookie.

Method naming: camelCase, usually verb + noun, e.g., sendMessage. In OOP, protected/private methods may be prefixed with an underscore.

public getUserName()
protected _getTotalAmount()
private _setBlanceAmount()

Variable naming: camelCase for regular variables (e.g., $workYears); protected/private properties prefixed with an underscore (e.g., $_salaryAmount).

Constant naming: uppercase with underscores, e.g., define('CURRENT_SCRIPT', 'index.php'); and const TRANSACTION_TYPE = 'income';.

Global variable naming: PascalCase with a leading underscore, e.g., $_System_Config, $_Root_Path.

Indentation: use tabs (or 4 spaces as preferred) for indentation; keep braces on their own line to avoid confusion in nested logic.

Operator spacing: place a single space before and after binary operators.

Control Flow Formatting

Braces occupy a separate line. Example of branch statements:

if($age >= 18 && $age <= 30)
{
  echo 'young man';
}
else if($age > 30 && $age <= 60)
{
  echo 'middle aged';
}
else
{
  echo 'old man';
}

switch($status)
{
  case 'forbidden':
    echo 'login forbidden';
    break;
  case 'normal':
    echo 'login in';
    break;
  default:
    echo 'status is wrong';
    break;
}

Loop statements follow the same brace style:

while($condition)
{
  // statements
}

foreach($arrayList as $arrayKey => $arrayItem)
{
  // statements
}

do
{
  // statements
} while($condition);

for($i = $start; $i < $end; $i++)
{
  // statements
}

Comment Writing Conventions

Comments improve readability, aid code layout planning, and can be processed by tools like phpDocumentor to generate documentation.

Block comments: used for file descriptions, large module overviews, or multi‑line notes.

Line comments: complement block comments for detailed explanations within a module.

Comments should describe *why* something is done rather than *what* the code does.

Example of a phpDocumentor docblock:

/**
 * Connect to the database
 * @param string $dbhost Database server address
 * @param string $dbuser Database username
 * @param string $dbpwd Database password
 */

PHP Programming Standards

File tags: always use full <?php tags; avoid short tags.

File and directory naming: meaningful English names, using letters, numbers, underscores or hyphens; .php extension required; use camelCase for multi‑word names.

Directory structure: separate directories for app, class, config, data, docs, htdocs, images, css, js, lib, templates, tmp, cache, session, etc., to aid collaboration and maintenance.

Variable naming: start with a letter or underscore, followed by letters, numbers, or underscores; use camelCase; global variables prefixed with an underscore.

Class and interface naming: start with an uppercase letter; multi‑word names use PascalCase; interface names prefixed with an i (e.g., iUserRepository); class name matches file name.

Database naming: all lowercase; table names use underscores; fields use lowercase without underscores; optional prefix with table initial.

Comment standards: place program comments before code, use /** */ for block comments, // for line comments; keep comments concise and focused on purpose.

Code style: use 4 spaces for indentation (or tabs if preferred); surround assignment operators with spaces; limit lines to ~80 characters; break long strings with concatenation; prefer built‑in constants (e.g., PHP_EOL) and commas in echo statements; use printf for formatted output; avoid overusing syntactic sugar.