php-parser

PHP Parser

A high-performance, comprehensive PHP parser implementation in Go with full PHP 8.4 syntax support. This parser provides complete lexical analysis, syntax parsing, and AST generation capabilities for PHP code.

中文文档 | Documentation | Examples

Features

🚀 Core Capabilities

• Full PHP 8.4 Compatibility: Complete syntax support including modern PHP features
• High Performance: Optimized lexer and parser with benchmark support
• Complete AST: Rich Abstract Syntax Tree with 150+ node types
• Error Recovery: Robust error handling with partial parsing capabilities
• Position Tracking: Precise line/column information for all tokens and nodes
• Visitor Pattern: Comprehensive AST traversal and transformation utilities

📦 Components

• Lexer: State-machine based tokenizer with 11 parsing states
• Parser: Recursive descent parser with Pratt parsing for expressions
• AST: Interface-based node system with visitor pattern support
• CLI Tool: Feature-rich command-line interface for parsing and analysis
• Examples: 5 comprehensive examples demonstrating different use cases

🎯 Use Cases

• Static Analysis: Code quality tools, linters, security scanners
• Development Tools: IDEs, language servers, code formatters
• Documentation: API documentation generators, code visualization
• Refactoring: Automated code transformation and migration tools
• Testing: Code coverage analysis, mutation testing
• Transpilation: PHP-to-PHP transformations, version compatibility

Quick Start

Installation

go get github.com/wudi/php-parser

Basic Usage

package main

import (
    "fmt"
    "github.com/wudi/php-parser/lexer"
    "github.com/wudi/php-parser/parser"
)

func main() {
    code := `<?php
    function hello($name) {
        return "Hello, " . $name . "!";
    }
    echo hello("World");
    ?>`

    l := lexer.New(code)
    p := parser.New(l)
    program := p.ParseProgram()

    if len(p.Errors()) > 0 {
        for _, err := range p.Errors() {
            fmt.Printf("Error: %s\n", err)
        }
        return
    }

    fmt.Printf("Parsed %d statements\n", len(program.Body))
    fmt.Printf("AST: %s\n", program.String())
}

Command Line Tool

Build and use the CLI tool:

# Build the parser
go build -o php-parser ./cmd/php-parser

# Parse a PHP file
./php-parser example.php

# Show tokens and AST
./php-parser -tokens -ast example.php

# Output as JSON
./php-parser -format json example.php

# Parse from stdin
echo '<?php echo "Hello"; ?>' | ./php-parser

Architecture

Project Structure

php-parser/
├── ast/            # Abstract Syntax Tree implementation
│   ├── node.go     # 150+ AST node types (6K+ lines)
│   ├── kind.go     # AST node type constants  
│   ├── visitor.go  # Visitor pattern utilities
│   └── builder.go  # AST construction helpers
├── lexer/          # Lexical analyzer  
│   ├── lexer.go    # Main lexer with state machine (1.5K+ lines)
│   ├── token.go    # PHP token definitions (150+ tokens)
│   └── states.go   # Lexer state management
├── parser/         # Syntax parser
│   ├── parser.go   # Recursive descent parser (7K+ lines)
│   ├── pool.go     # Parser pooling for concurrency
│   └── testdata/   # Test cases and fixtures
├── cmd/            # Command-line interface
│   └── php-parser/ # CLI implementation (244 lines)
├── examples/       # Usage examples and tutorials
│   ├── basic-parsing/      # Fundamental parsing concepts
│   ├── ast-visitor/        # Visitor pattern examples
│   ├── token-extraction/   # Lexical analysis
│   ├── error-handling/     # Error recovery examples
│   └── code-analysis/      # Static analysis tools
├── errors/         # Error handling utilities  
└── scripts/        # Development and testing scripts

Code Statistics: 18,500+ lines of Go code across 16 source files with 29 test files

Core Components

Lexer (Tokenizer)

• 11 Parsing States: Including ST_IN_SCRIPTING, ST_DOUBLE_QUOTES, ST_HEREDOC
• 150+ Token Types: Complete PHP 8.4 token compatibility
• State Machine: Handles complex PHP syntax like string interpolation
• Shebang Support: Recognizes executable PHP files
• Position Tracking: Line, column, and offset information

Parser (Syntax Analyzer)

• Recursive Descent: Clean, maintainable parsing architecture
• Pratt Parsing: Elegant operator precedence handling (14 levels)
• Error Recovery: Continues parsing after errors to find multiple issues
• 50+ Parse Functions: Comprehensive PHP syntax coverage
• Alternative Syntax: Full support for if:...endif; style constructs

AST (Abstract Syntax Tree)

• Interface-Based: Clean separation between node types
• 150+ Node Types: Matching PHP's official zend_ast.h constants
• Visitor Pattern: Easy traversal and transformation
• JSON Serialization: Export AST for external tools
• Position Preservation: All nodes retain source location

PHP 8.4 Language Support

Operators

• Arithmetic: +, -, *, /, %, ** (power)
• Assignment: =, +=, -=, *=, /=, %=, **=, .=, ??=, etc.
• Comparison: ==, ===, !=, !==, <, <=, >, >=, <=> (spaceship)
• Logical: &&, ||, !, and, or, xor
• Bitwise: &, |, ^, ~, <<, >>
• Null Coalescing: ??, ??=

Language Constructs

• Control Structures: if, else, elseif, while, for, foreach, switch
• Alternative Syntax: if:...endif;, while:...endwhile;, switch:...endswitch;
• Functions: Parameters, return types, references, variadic
• Classes: Properties, methods, constants, inheritance, interfaces
• Namespaces: Full namespace support with use statements
• Special: __halt_compiler(), match expressions, attributes

Modern PHP Features

• Typed Properties: private int $id, public ?string $name
• Union Types: int|string, Foo|Bar|null
• Intersection Types: Foo&Bar
• Match Expressions: Pattern matching with match()
• Attributes: #[Route('/api')] syntax
• Nullsafe Operator: $user?->getProfile()?->getName()
• Class Constants with Visibility: private const SECRET = 'value'

Examples

The examples/ directory contains comprehensive demonstrations:

1. Basic Parsing

Learn fundamental parsing concepts and AST examination.

cd examples/basic-parsing && go run main.go

2. AST Visitor Pattern

Implement custom visitors for code analysis and traversal.

cd examples/ast-visitor && go run main.go

3. Token Extraction

Explore lexical analysis and token statistics.

cd examples/token-extraction && go run main.go

4. Error Handling

Understand parser error recovery and reporting.

cd examples/error-handling && go run main.go  

5. Code Analysis

Build static analysis tools with metrics and quality assessment.

cd examples/code-analysis && go run main.go

Each example includes:

• Runnable Code: Complete working examples
• Documentation: Detailed README with explanations
• Real PHP Samples: Realistic code for testing
• Progressive Complexity: From beginner to advanced

Testing

Running Tests

# Run all tests
go test ./...

# Run with verbose output
go test ./... -v

# Run specific component tests
go test ./lexer -v
go test ./parser -v  
go test ./ast -v

# Run benchmarks
go test ./parser -bench=.
go test ./parser -bench=. -benchmem

# Run specific test cases
go test ./parser -run=TestParsing_TryCatchWithStatements
go test ./parser -run=TestParsing_ClassMethodsWithVisibility

Test Coverage

The project maintains comprehensive test coverage with:

• 29 Test Files: Covering all major components
• 200+ Test Cases: Including edge cases and error conditions
• Real-world Testing: Compatibility tests against major PHP frameworks
• Benchmark Tests: Performance validation and optimization

Compatibility Testing

Test against popular PHP codebases:

# Test with WordPress
go run scripts/test_folder.go /path/to/wordpress-develop

# Test with Laravel  
go run scripts/test_folder.go /path/to/framework

# Test with Symfony
go run scripts/test_folder.go /path/to/symfony

Performance

Benchmarks

• Simple Statements: ~1.6μs per parse
• Complex Expressions: ~4μs per parse
• Large Files: Efficient memory usage with streaming
• Concurrent Parsing: Parser pool support for parallel processing

Memory Usage

• Low Footprint: Minimal memory allocation per parse
• Streaming: Large file support without loading entire content
• Pool Pattern: Reusable parser instances for server applications

Development

Requirements

• Go 1.21+
• Optional: PHP 8.4 for compatibility testing

Development Commands

# Build CLI tool
go build -o php-parser ./cmd/php-parser

# Run all tests
go test ./...

# Run performance benchmarks
go test ./parser -bench=. -run=^$

# Test with memory profiling
go test ./parser -bench=. -benchmem

# Compatibility testing
go run scripts/test_folder.go /path/to/php/codebase

# Clean build artifacts
go clean
rm -f php-parser main

Contributing

We welcome contributions! Please see our contributing guidelines:

1. Fork the repository
2. Create a feature branch: git checkout -b feature-name
3. Write tests for your changes
4. Ensure all tests pass: go test ./...
5. Run linting: go fmt ./...
6. Submit a pull request

Development Guidelines

• Follow Go coding standards (gofmt, effective Go)
• Maintain PHP compatibility with official implementation
• Add comprehensive tests for new features
• Reference PHP's official grammar at /php-src/Zend/zend_language_parser.y
• Update documentation for new features

Use Cases in Production

Static Analysis Tools

• Code Quality: Detect anti-patterns, complexity metrics
• Security Scanning: Find vulnerabilities, injection risks
• Style Checking: Enforce coding standards and conventions

Development Tools

• IDEs: Syntax highlighting, auto-completion, error detection
• Language Servers: LSP implementation for editor support
• Code Formatters: Consistent code styling and formatting

Documentation Tools

• API Generators: Extract documentation from code and comments
• Code Visualization: Generate class diagrams, call graphs
• Dependency Analysis: Track code relationships and coupling

Migration and Refactoring

• Version Upgrades: PHP version compatibility transformations
• Framework Migrations: Automated code pattern updates
• Code Modernization: Apply modern PHP practices and syntax

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgments

• PHP Team: For the official PHP language specification
• Go Community: For excellent tooling and ecosystem
• Contributors: Everyone who has contributed to this project

Links

• Repository: github.com/wudi/php-parser
• Issues: Report bugs and feature requests
• Documentation: Detailed API documentation
• Examples: Code examples and tutorials

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Built with ❤️ in Go | PHP 8.4 Compatible | Production Ready