Oak CSS Parser

High-performance incremental CSS parser for the oak ecosystem with flexible configuration, optimized for web development and styling analysis.

🎯 Overview

Oak-css is a robust parser for CSS, designed to handle complete CSS syntax including modern features. Built on the solid foundation of oak-core, it provides both high-level convenience and detailed AST generation for web development and styling analysis.

✨ Features

• Complete CSS Syntax: Supports all CSS 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_css::CssParser;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let parser = CssParser::new();
    let css_content = r#"
body {
    margin: 0;
    padding: 0;
    font-family: Arial, sans-serif;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
}
    "#;
    
    let stylesheet = parser.parse_stylesheet(css_content)?;
    println!("Parsed CSS stylesheet successfully.");
    Ok(())
}

📋 Parsing Examples

Rule Parsing

use oak_css::{CssParser, ast::Rule};

let parser = CssParser::new();
let css_content = "h1 { color: red; font-size: 2em; font-weight: bold; }";

let rule = parser.parse_rule(css_content)?;
println!("Selector: {}", rule.selector);
println!("Declarations: {}", rule.declarations.len());

Selector Parsing

use oak_css::{CssParser, ast::Selector};

let parser = CssParser::new();
let selector = parser.parse_selector(".container .item:hover > .child")?;
println!("Selector complexity: {}", selector.complexity());
println!("Specificity: {:?}", selector.specificity());

Declaration Parsing

use oak_css::{CssParser, ast::Declaration};

let parser = CssParser::new();
let declaration = parser.parse_declaration("margin: 10px 5px 20px 15px")?;
println!("Property: {}", declaration.property);
println!("Value tokens: {}", declaration.value.len());

🔧 Advanced Features

Token-Level Parsing

use oak_css::{CssParser, lexer::Token};

let parser = CssParser::new();
let tokens = parser.tokenize(".class { color: #ff0000; }")?;
for token in tokens {
    println!("{:?}", token.kind);
}

Error Handling

use oak_css::CssParser;

let parser = CssParser::new();
let invalid_css = r#"
body {
    color: red
    font-size: 16px;  // Missing semicolon
    margin: 10px
}
"#;

match parser.parse_stylesheet(invalid_css) {
    Ok(stylesheet) => println!("Parsed CSS stylesheet successfully."),
    Err(e) => {
        println!("Parse error at line {} column {}: {}", 
            e.line(), e.column(), e.message());
        if let Some(context) = e.context() {
            println!("Error context: {}", context);
        }
    }
}

🏗️ AST Structure

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

• Stylesheet: Root container for CSS rules
• Rule: CSS rules with selectors and declarations
• Selector: CSS selectors with specificity calculation
• Declaration: Property-value pairs
• Function: CSS functions like rgb(), calc(), etc.
• AtRule: CSS at-rules like @media, @import, etc.

📊 Performance

• Streaming: Parse large CSS files 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-css integrates seamlessly with:

• Web Development: Parse CSS for web applications
• Styling Analysis: Analyze CSS for optimization and linting
• Build Tools: Integrate with CSS processing pipelines
• IDE Support: Language server protocol compatibility
• Preprocessors: Handle CSS-like preprocessor syntax

📚 Examples

Check out the examples directory for comprehensive examples:

• Complete CSS stylesheet parsing
• Selector analysis and specificity calculation
• Property validation and transformation
• Integration with development workflows

🤝 Contributing

Contributions are welcome!

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