Crate oak_scala 

🛠️ Scala Parser Developer Guide

Scala support for the Oak language framework.

This guide is designed to help you quickly get started with developing and integrating oak-scala.

🚦 Quick Start

Add the dependency to your Cargo.toml:

[dependencies]
oak-scala = { path = "..." }

Basic Parsing Example

The following is a standard workflow for parsing Scala source files, supporting Scala 2 and Scala 3 syntax:

use oak_scala::{ScalaParser, SourceText, ScalaLanguage};

fn main() {
    // 1. Prepare source code
    let code = r#"
        package com.example

        import scala.util.Random

        object Dice {
            def roll(): Int = {
                Random.nextInt(6) + 1
            }
        }
    "#;
    let source = SourceText::new(code);

    // 2. Initialize parser
    let config = ScalaLanguage::new();
    let parser = ScalaParser::new(&config);

    // 3. Execute parsing
    let result = parser.parse(&source);

    // 4. Handle results
    if result.is_success() {
        println!("Parsing successful! AST node count: {}", result.node_count());
    } else {
        eprintln!("Errors found during parsing.");
        for diag in result.diagnostics() {
            println!("[{}:{}] {}", diag.line, diag.column, diag.message);
        }
    }
}

🔍 Core API Usage

1. Syntax Tree Traversal

After a successful parse, you can use the built-in visitor pattern or manually traverse the Green/Red Tree to extract Scala specific constructs like package clauses, imports, object/class/trait definitions, and method declarations.

2. Incremental Parsing

Scala projects can be large. oak-scala supports sub-millisecond incremental updates for efficient IDE feedback:

// Re-parse only the modified section
let new_result = parser.reparse(&new_source, &old_result);

3. Error Recovery

The parser is designed for industrial-grade fault tolerance, recovering gracefully from missing braces or malformed declarations to provide continuous feedback in IDEs.

🏗️ Architecture Overview

• Lexer: Tokenizes Scala source text, supporting Scala 3’s indentation-based syntax and Scala 2’s traditional syntax.
• Parser: A high-performance recursive descent parser handling complex Scala features like implicits, generics, and pattern matching.
• AST: A strongly-typed, lossless syntax tree that preserves all trivia (comments/whitespace) for refactoring and formatting tools.

🔗 Advanced Resources

• Full Examples: Check the examples/ folder in the project root.
• API Documentation: Run cargo doc --open for detailed type definitions.
• Test Cases: See tests/readme.md for details on our snapshot-based testing.

Re-exports

pub use crate::ast::ScalaRoot;

pub use crate::builder::ScalaBuilder;

pub use crate::language::ScalaLanguage;

pub use crate::lexer::ScalaLexer;

pub use crate::parser::ScalaParser;

pub use crate::lsp::highlighter::ScalaHighlighter;

pub use crate::lsp::ScalaLanguageService;

pub use crate::lsp::formatter::ScalaFormatter;

pub use crate::mcp::serve_scala_mcp;

Modules

ast

AST module.

builder

Builder module.

language

Syntax kind module. Language configuration module.

lexer

Lexer module.

lsp

Syntax module. LSP module.

mcp

MCP module.

parser

Parser module.

Traits

ElementType

A trait for types that represent an element’s kind in a syntax tree.

TokenType

A trait for types that represent a token’s kind in a specific language.