Autoload

Definitions

1. A mechanism that loads the file defining a class or module automatically the first time the code refers to it, instead of requiring explicit include or require statements at the top of each file. In PHP, spl_autoload_register lets an application install autoloader functions, and the PSR-4 standard maps namespace prefixes to directories so that a class name determines its file path; Composer generates a PSR-4 autoloader for a project and all its dependencies. In Ruby, Kernel#autoload registers a file to load when a constant is first referenced, and Rails uses the Zeitwerk loader, the only mode since Rails 7, which requires file names to match constant names and supports reloading code in development without restarting the server. Emacs Lisp uses autoload cookies to defer loading packages until one of their commands is used. Autoloading keeps startup fast and code tidy, at the cost of hiding load order, so it relies heavily on strict naming conventions.

   In plain English: A system that automatically finds and loads the right code file when your program needs a class, so you do not have to manually list every file.

   Example: "PSR-4 autoloading means you never write a require statement — Composer resolves the file from the namespace."

Related Terms

• Active Record
• Artisan
• Blade
• Block
• Composer
• Eloquent
• Gem
• HHVM
• Laravel
• PHPUnit
• Proc
• PSR
• Rails
• Rake
• XHP
• Null Coalescing
• Output Buffering
• Rack
• Ruby Gem
• Ruby on Rails
• Symbol