As a classic development language, PHP is widely used in the field of Web development around the world. As the latest version of the PHP series, PHP7 not only has significant improvements in performance and efficiency, but also has more advanced and complex underlying development principles. This article will delve into the underlying development principles of PHP7 and help readers further understand the architecture and component structure of the PHP kernel.
First of all, we need to understand the basis of the underlying development principles of PHP7, which is the Zend engine. The Zend engine is part of the PHP interpreter, which is responsible for parsing PHP code into executable instructions and implementing runtime dynamic features. Zend engine is the core of PHP7. It implements the parsing and execution of PHP code through components such as lexical analyzer, syntax analyzer, compiler and executor.
In the Zend engine, the lexical analyzer is responsible for decomposing PHP code into lexical units, such as keywords, identifiers, constants, operators, etc. The syntax analyzer organizes the lexical units and generates an abstract syntax tree (AST) of the PHP code. The compiler converts the AST into a low-level opcode instruction set and generates an executable ZendVM instruction sequence. The executor is responsible for executing the ZendVM instruction sequence to implement line-by-line execution of PHP code and access to variables.
In addition to the Zend engine, PHP7 also introduces some new components and technologies to further improve performance and efficiency. The most important one is the PHPNG (PHP Next Generation) project, which has been comprehensively optimized in terms of memory management and execution model. PHPNG adopts a new memory allocator and optimized execution model, which greatly improves the execution speed and memory utilization of PHP code.
In addition, PHP7 also introduces a new abstract syntax tree (AST) data structure to represent the structure of PHP code during compilation and execution. AST can describe the structure of PHP code more accurately and efficiently, thereby improving the efficiency of compilation and execution.
In addition, PHP7 also introduces some new syntax and language features to enhance the functionality and flexibility of PHP. For example, PHP7 supports strict type checking and declaration, allowing developers to define the types of variables and functions more clearly and safely. At the same time, PHP7 also introduces new operators and syntax, such as the spaceship operator () and the null coalescing operator (??), which further simplifies code writing and logical expression.
In addition to the underlying Zend engine and components, PHP7 also supports a series of extensions and libraries, providing a wealth of functions and features. For example, PHP7 natively supports extensions to multi-threading and asynchronous programming, allowing PHP to better cope with high concurrency and high load scenarios. At the same time, PHP7 also supports extensions to new protocols and standards, such as HTTP/2 and WebSocket, further expanding the application fields of PHP.
To sum up, the underlying development principles of PHP7 include the Zend engine and a series of components, such as lexical analyzer, syntax analyzer, compiler and executor. PHP7 also introduces some new technologies and features, such as PHPNG project, new AST data structure and strict type checking. By in-depth understanding of the underlying development principles of PHP7, we can better understand PHP's core architecture and component structure, and then use PHP technology more efficiently and flexibly in actual development.
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