PHP8正式版发布，带来了注解和JIT

PHP 8 Release Summary

PHP 8 has been officially released, introducing significant changes, numerous new features, performance optimizations, such as named arguments, union types, attributes, constructor property promotion, match expressions, nullsafe operator, JIT, as well as improvements to the type system, error handling, and consistency.

Key Features and Improvements

• Named Arguments: Allow skipping optional parameters and are order-independent, which makes the code more readable.
• Attributes (Annotations): The new syntax does not affect lower versions since # is a comment symbol in PHP.
• Constructor Property Promotion: Reduces boilerplate code by allowing properties to be defined in the constructor.
• Union Types: Support for declaring more than one type, leading to better type checking.
• Match Expression: A more powerful and concise alternative to the switch statement which performs strict comparisons.
• Nullsafe Operator: Simplifies the syntax for null checks within method call chains, making the code cleaner.
• Saner String to Number Comparisons: Numbers are now compared as numbers rather than strings when dealing with numeric strings.
• Consistent Type Errors for Internal Functions: Most internal functions now throw an error exception if parameter validation fails.

JIT Compilation Engine

PHP 8 introduces two JIT compilation engines, with the tracing JIT showing the most promise by improving performance up to three times in synthetic benchmarks and 1.5 to 2 times in some long-running applications.

Additional Enhancements

Other improvements include enhancements to the type system and error handling, syntax adjustments, new classes, interfaces, and functions. Opaque objects replace resource types for Curl, Gd, Sockets, OpenSSL, XMLWriter, and XML extensions.

More detailed information about the new features and functionalities can be found on the official PHP website. Interested readers can also refer to Nikic's PPT shared at a previous PHPCon for an in-depth look at PHP 8's features.