Oak Regex Parser

High-performance incremental regular expression parser for the oak ecosystem with flexible configuration, optimized for pattern matching and text processing.

🎯 Overview

Oak Regex is a robust parser for regular expressions, designed to handle complete regex syntax including modern features. Built on the solid foundation of oak-core, it provides both high-level convenience and detailed AST generation for pattern matching and text processing.

✨ Features

• Complete Regex Syntax: Supports all regex features including modern specifications
• Full AST Generation: Generates comprehensive Abstract Syntax Trees
• Lexer Support: Built-in tokenization with proper span information
• Error Recovery: Graceful handling of syntax errors with detailed diagnostics

🚀 Quick Start

Basic example:

use oak_regex::{Parser, RegexLanguage, SourceText};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let parser = Parser::new();
    let source = SourceText::new(r#"
        [a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}
    "#);
    
    let result = parser.parse(&source);
    println!("Parsed regex successfully.");
    Ok(())
}

📋 Parsing Examples

Email Pattern Parsing

use oak_regex::{Parser, RegexLanguage, SourceText};

let parser = Parser::new();
let source = SourceText::new(r#"
    [a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}
"#);

let result = parser.parse(&source);
println!("Email pattern parsed successfully.");

Complex Pattern Parsing

use oak_regex::{Parser, RegexLanguage, SourceText};

let parser = Parser::new();
let source = SourceText::new(r#"
    (?:(?<=\s)|^)(?:https?:\/\/)?(?:www\.)?[a-zA-Z0-9-]+\.[a-zA-Z]{2,}(?:\/\S*)?(?=\s|$)
"#);

let result = parser.parse(&source);
println!("URL pattern parsed successfully.");

Group and Alternation Parsing

use oak_regex::{Parser, RegexLanguage, SourceText};

let parser = Parser::new();
let source = SourceText::new(r#"
    (?:cat|dog|bird)(?:\s+(?:is|are)\s+(?:brown|black|white))?
"#);

let result = parser.parse(&source);
println!("Group and alternation parsed successfully.");

🔧 Advanced Features

Token-Level Parsing

use oak_regex::{Parser, RegexLanguage, SourceText};

let parser = Parser::new();
let source = SourceText::new(r#"\d{3}-\d{2}-\d{4}"#);
let result = parser.parse(&source);
println!("Token parsing completed.");

Error Handling

use oak_regex::{Parser, RegexLanguage, SourceText};

let parser = Parser::new();
let source = SourceText::new(r#"
    [a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}
    // Unclosed character class
    [a-z
"#);

let result = parser.parse(&source);
if let Some(errors) = result.result.err() {
    println!("Parse errors found: {:?}", errors);
} else {
    println!("Parsed successfully.");
}

🏗️ AST Structure

The parser generates a comprehensive AST with the following main structures:

• RegexRoot: Root container for regular expressions
• Alternation: Alternation expressions (|)
• Group: Grouping expressions (capturing and non-capturing)
• Quantifier: Quantifiers (?, *, +, {n,m})
• CharacterClass: Character classes and ranges
• Assertion: Assertions (^, $, \b, \B, lookaround)
• Literal: Literal characters and escaped sequences

📊 Performance

• Streaming: Parse large regex patterns without loading entirely into memory
• Incremental: Re-parse only changed sections
• Memory Efficient: Smart AST node allocation
• Fast Recovery: Quick error recovery for better IDE integration

🔗 Integration

Oak Regex integrates seamlessly with:

• Text Processing: Pattern matching and text extraction
• Validation: Input validation and sanitization
• IDE Support: Syntax highlighting and autocompletion for regex
• Code Generation: Generating code from regex patterns
• Static Analysis: Analyzing regex patterns for optimization

📚 Examples

Check out the examples directory for comprehensive examples:

• Complete regex pattern parsing
• Complex pattern analysis
• Pattern optimization
• Integration with text processing workflows

🤝 Contributing

Contributions are welcome!

Please feel free to submit pull requests at the project repository or open issues.