What Are the Differences Between PSR-0 and PSR-4?

Question

Recently I\'ve read about namespaces and how they are beneficial. I\'m currently creating a project in Laravel and trying to move from class map autoloading to namespacing.

Answer 1

Here are the major differences,

1. For example if you define that the Acme\Foo\ namespace is anchored in src/,

• with PSR-0 it means it will look for Acme\Foo\Bar in src/Acme/Foo/Bar.php
• while in PSR-4 it will look for Acme\Foo\Bar in src/Bar.php(where Bar class is).

2. PSR-4 does not convert underscores to directory separators

3. You would prefer using PSR-4 with namespaces

4. PSR-0 will not work even if the class name is different from file name, like considering above example:

• Acme\Foo\Bar ---> src/Acme/Foo/Bar.php (for Bar class) will work
• Acme\Foo\Bar ---> src/Acme/Foo/Bar2.php (for Bar class) will not work