Naming classes, methods, functions and variables [duplicate]

Question

There are 3 important naming conventions:

1. with_underscores
2. PascalCased
3. camelCased

Other variants are not important because they are not commonly used.

For variables it seems that the one with underscores is the most used by developers so I'll stick with that. I think it's the same for functions.

But what about class, and method names? Which of these 3 is the most used by developers for such constructs? (personally, it's 3. for methods and 2. for classes)

Please do not post things like "use what you feel is right", because the code I'm writing is API for other developers, and I'd like to adopt the most popular coding style :)

Answer 1

I had the same question about a year ago so I looked at some code myself. Here is what I found (constants were ALL_CAPS in every project, by the way):

╔══════════════════╦═════════════╦════════════╦══════════════╦════════════╦════════════╗
║    PHP Project   ║   Classes   ║  Methods   ║  Properties  ║ Functions  ║ Variables  ║
╠══════════════════╬═════════════╬════════════╬══════════════╬════════════╬════════════╣
║ Akelos           ║ PascalCase  ║ camelCase  ║ camelCase    ║ lower_case ║ lower_case ║
║ CakePHP          ║ PascalCase  ║ camelCase  ║ camelCase    ║ camelCase  ║ camelCase  ║
║ CodeIgniter      ║ Proper_Case ║ lower_case ║ lower_case   ║ lower_case ║ lower_case ║
║ Concrete5 CMS    ║ PascalCase  ║ camelCase  ║ camelCase    ║ lower_case ║ lower_case ║
║ Doctrine ORM     ║ PascalCase  ║ camelCase  ║ camelCase    ║ camelCase  ║ camelCase  ║
║ Drupal CMS       ║ PascalCase  ║ camelCase  ║ camelCase    ║ lower_case ║ lower_case ║
║ Joomla CMS       ║ PascalCase  ║ camelCase  ║ camelCase    ║ camelCase  ║ camelCase  ║
║ modx CMS         ║ PascalCase  ║ camelCase  ║ camelCase    ║ camelCase  ║ lower_case ║
║ Pear             ║ PascalCase  ║ camelCase  ║ camelCase    ║ ---------- ║ ---------- ║
║ Prado            ║ PascalCase  ║ camelCase  ║ Pascal/camel ║ ---------- ║ lower_case ║
║ SimplePie RSS    ║ PascalCase  ║ lower_case ║ lower_case   ║ lower_case ║ lower_case ║
║ Symfony          ║ PascalCase  ║ camelCase  ║ camelCase    ║ camelCase  ║ camelCase  ║
║ Laravel          ║ PascalCase  ║ camelCase  ║ camelCase    ║ camelCase  ║ camelCase  ║
║ Yii 2            ║ PascalCase  ║ camelCase  ║ camelCase    ║ camelCase  ║ camelCase  ║
║ Phalcon          ║ PascalCase  ║ camelCase  ║ camelCase    ║ camelCase  ║ camelCase  ║
║ Slim Framework   ║ PascalCase  ║ camelCase  ║ camelCase    ║ camelCase  ║ camelCase  ║
║ FuelPHP          ║ PascalCase  ║ camelCase  ║ camelCase    ║ camelCase  ║ camelCase  ║
║ PHPPixie         ║ PascalCase  ║ camelCase  ║ camelCase    ║ camelCase  ║ camelCase  ║
║ Laminas Project  ║ PascalCase  ║ camelCase  ║ camelCase    ║ camelCase  ║ camelCase  ║
║ Fat-Free         ║ PascalCase  ║ camelCase  ║ camelCase    ║ camelCase  ║ camelCase  ║
║ Lumen            ║ PascalCase  ║ camelCase  ║ camelCase    ║ camelCase  ║ camelCase  ║
║ Flight           ║ PascalCase  ║ camelCase  ║ camelCase    ║ camelCase  ║ camelCase  ║
╚══════════════════╩═════════════╩════════════╩══════════════╩════════════╩════════════╝

So after looking at all this, I decided to go with:

• ClassName
• methodName
• propertyName
• function_name (meant for global functions)
• $variable_name

Answer 2

There is no such thing as "the most popular coding style", it's strictly a matter of your team's conventions and personal preferences. Since you are targeting developers, you should research popular conventions for your platform and follow the one you feel is more convenient, readable and, well, closer to your personal style. For PHP a popular set of naming conventions is Zend Framework's.

Being consistent with the naming convention you choose is more important than the convention itself.

Answer 3

While it may not be as ubiquitous as the Java version, following the Apache PHP Style Guide certainly won't hurt. For naming conventions:

Naming: FunctionNamesLike, $localVariableName, $objectVariable, ClassNamesLike, MethodNamesLike, CONSTANTS_LIKE_THIS. Global names (classes, functions, variables, defines) must be prefixed to prevent naming clashes with PHP itself. This approach includes preventing prefixes that clash with PHP or are likely to. Apart from constants, prevent underscores in your names unless you simulate namespaces and are sure you can switch to real namespaces once PHP has them (and of course for object variables).

Following this, class and method names would be PascalCased.

There are a number of other reasonable style guides out there as well, as listed here. Most seem to agree that class names should be PascalCased but some, including the MIT style guide, indicate methods should be camelCased.

So, four years after I originally answered this question, I would say go with the accepted answer above.

Answer 4

We have this weird system where everything has it's own convention:

• ClassesAreLikeThis.
• variablesAndFunctionsLikeThis
• UNLESS_THEY_ARE_CONSTANTS
• andMemberVariablesEndWith_

Answer 5

I personally find camelcase to be more natural when coding variables, but because variables in PHP are case sensitive, and it's no fun hunting through code looking for a variable you forgot to make camelcase, I always use snake case for variables.

While its true that the conventions are mutable, coding after someone that has used camelcase on variables, and trying to be sure you always use their convention for THAT variable, can be frustrating.