PSR-0

PSR-0 is a deprecated PHP Standards Recommendation that defined a standard for autoloading classes in PHP applications, specifying how class names should map to file system paths. It was part of the PHP-FIG (Framework Interoperability Group) standards to improve interoperability between PHP frameworks and libraries. The standard aimed to eliminate the need for manual include or require statements by establishing consistent naming conventions.

Also known as: PSR0, PHP Standard Recommendation 0, Autoloading Standard, PSR-0 Autoloading, PHP-FIG PSR-0

Why learn PSR-0?

Developers should learn PSR-0 primarily for historical context and maintaining legacy PHP codebases, as it was widely adopted in PHP 5.3+ projects before being superseded by PSR-4. It is useful when working with older frameworks like Zend Framework 1 or Symfony 2, where understanding autoloading conventions is essential for debugging and migration. Knowledge of PSR-0 helps in transitioning projects to modern standards and comprehending the evolution of PHP development practices.

Learning Resources

• docs: PHP-FIG PSR-0 Documentation
• tutorial: PHP The Right Way - Autoloading
• docs: Composer Autoloading Guide
• video: Laracasts: Autoloading in PHP