Oak Haskell Parser

High-performance incremental Haskell parser for the oak ecosystem with flexible configuration, optimized for static analysis and code generation.

🎯 Overview

Oak Haskell is a robust parser for Haskell, designed to handle complete Haskell syntax including modern extensions. Built on the solid foundation of oak-core, it provides both high-level convenience and detailed AST generation for static analysis and code generation.

✨ Features

• Complete Haskell Syntax: Supports all Haskell features including modern extensions
• 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_haskell::{Parser, HaskellLanguage, SourceText};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let parser = Parser::new();
    let source = SourceText::new(r#"
main :: IO ()
main = putStrLn "Hello, Haskell!"

add :: Int -> Int -> Int
add x y = x + y
    "#);
    
    let result = parser.parse(&source);
    println!("Parsed Haskell successfully.");
    Ok(())
}

📋 Parsing Examples

Function Parsing

use oak_haskell::{Parser, HaskellLanguage, SourceText};

let parser = Parser::new();
let source = SourceText::new(r#"
factorial :: Integer -> Integer
factorial 0 = 1
factorial n = n * factorial (n - 1)

main :: IO ()
main = do
    let result = factorial 5
    putStrLn $ "Factorial of 5 is: " ++ show result
"#);

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

Data Type Parsing

use oak_haskell::{Parser, HaskellLanguage, SourceText};

let parser = Parser::new();
let source = SourceText::new(r#"
data Tree a = Empty | Node a (Tree a) (Tree a)
    deriving (Show, Eq)

treeSum :: Tree Int -> Int
treeSum Empty = 0
treeSum (Node value left right) = value + treeSum left + treeSum right

main :: IO ()
main = do
    let tree = Node 1 (Node 2 Empty Empty) (Node 3 Empty Empty)
    putStrLn $ "Sum of tree values: " ++ show (treeSum tree)
"#);

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

🔧 Advanced Features

Token-Level Parsing

use oak_haskell::{Parser, HaskellLanguage, SourceText};

let parser = Parser::new();
let source = SourceText::new("let x = 42 in x + 1");
let result = parser.parse(&source);
println!("Token parsing completed.");

Error Handling

use oak_haskell::{Parser, HaskellLanguage, SourceText};

let parser = Parser::new();
let source = SourceText::new(r#"
-- Invalid Haskell code example
brokenFunction :: Int -> Int
brokenFunction x =
    let y = x + 1
    -- Missing 'in' keyword
"#);

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:

• HaskellModule: Root container for Haskell modules
• Declaration: Top-level declarations including functions and data types
• Expression: Haskell expressions including literals, applications, and lambdas
• Pattern: Pattern matching constructs
• Type: Haskell type system constructs
• Statement: Various statement types including do-notation

📊 Performance

• Streaming: Parse large Haskell 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 Haskell integrates seamlessly with:

• Static Analysis: Code quality and security analysis
• Code Generation: Generating code from Haskell AST
• IDE Support: Language server protocol compatibility
• Refactoring: Automated code refactoring
• Documentation: Generating documentation from Haskell code

📚 Examples

Check out the examples directory for comprehensive examples:

• Complete Haskell module parsing
• Function and data type analysis
• Code transformation
• Integration with development workflows

🤝 Contributing

Contributions are welcome!

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