ThestaticreturntypeinPHP8meansthemethodisexpectedtoreturnaninstanceoftheclassit'scalledon,includinganychildclass.1.Itenableslatestaticbinding,ensuringthereturnedvaluematchesthecallingclass'stype.2.Comparedtoself,whichalwaysreferstothedefiningclass,an

NamedargumentsinPHP8allowpassingvaluestoafunctionbyspecifyingtheparameternameinsteadofrelyingonparameterorder.1.Theyimprovecodereadabilitybymakingfunctioncallsself-documenting,asseeninexampleslikeresizeImage(width:100,height:50,preserveRatio:true,ups

ConstructorpropertypromotioninPHP8allowsautomaticcreationandassignmentofclasspropertiesdirectlyfromconstructorparameters.Insteadofmanuallyassigningeachpropertyinsidetheconstructor,developerscanaddanaccessmodifier(public,protected,orprivate)totheparam

PHP8's mixed type allows variables, parameters, or return values ??to accept any type. 1. Mixed is suitable for scenarios that require high flexibility, such as middleware, dynamic data processing and legacy code integration; 2. It is different from union types because it covers all possible types, including new types in the future; 3. Be cautious when using them to avoid weakening type safety, and it is recommended to explain the expected types in conjunction with phpDoc. The rational use of mixed can improve code expression capabilities while maintaining the advantages of type prompts.

PHP8's match expression provides a cleaner conditional mapping through strict comparison. 1. Use strict equality (===) to avoid type conversion; 2. No break statement is required to prevent accidental penetration; 3. Direct return value can be assigned to variables; 4. Support multi-condition merging and sharing results. Suitable for precise matching and mapping input and output scenarios, such as HTTP status code processing; not suitable for range checks or loose comparisons.

JITinPHP8improvesperformancebycompilingfrequentlyexecutedcodeintomachinecodeatruntime.Insteadofinterpretingopcodeseachtime,JITidentifieshotsectionsofcode,compilesthemintonativemachinecode,cachesitforreuse,andreducesinterpretationoverhead.Ithelpsmosti

PHP8 attributes add metadata to code elements through structured methods. 1. They are attached above classes, methods, etc. using #[] syntax, such as #[Route('/home')] to define routes; 2. It is safer than PHPDoc, with type checking and compile-time verification; 3. Custom attributes need to define classes and apply, such as using ReflectionAttribute to create LogExecution log attributes; 4. Commonly used in frameworks to handle routing, verification, ORM mapping and other tasks, improving code readability and separating logical configurations; 5. It can be accessed through reflection, but excessive use should be avoided to avoid affecting code clarity.

The performance improvement of PHP8 mainly comes from the newly introduced JIT compiler and Zend engine optimization, but the benefits in actual applications vary by scenario. 1. The JIT compiler compiles some code into machine code at runtime, significantly improving the performance of CLI scripts or long-term APIs, but has limited effect in short-lifetime web requests; 2. OPcache improves and enhances opcode caching and preloading functions, reducing disk I/O and parsing overhead, especially for frameworks such as Laravel or Symfony; 3. Multiple internal optimizations such as more efficient string and array operations, smaller memory usage, etc. Although each improvement is small, it accumulates in small amounts; 4. The actual performance improvement depends on the application scenario, PHP8 can be fast 10 in computing-intensive tasks.