AZPOS - Multi-Language Lexicographic Position Library

A multi-language library for handling lexicographic position calculations, providing consistent implementations across TypeScript, Go, C#, Java, and Rust. Perfect for implementing fractional indexing in ordered lists and trees.

Features

• midpoint(a, b) - Return lexicographic midpoint between a and b, enforcing a < pos < b
• validate(pos) - Ensure position string is lowercase a–z and ≤ max length
• needsRebalance(a, b) - True if midpoint would exceed length or conflict
• rebalance3(a, b, c) - Return 3 evenly spaced values between "a" and "z"
• compare(a, b) - Lexicographic sort logic (safe in all langs)

Structure

• test-vectors/ - Shared golden test cases for consistency across all implementations
• ts/ - TypeScript implementation
• go/ - Go implementation
• csharp/ - C# (.NET) implementation
• java/ - Java implementation
• rust/ - Rust implementation
• scripts/ - Build and test automation scripts
• .github/workflows/ - CI/CD workflows for all languages

Testing

All implementations use the same test vectors from test-vectors/positions.json to ensure mathematical consistency across languages.

Getting Started

Each language implementation has its own README with specific setup instructions:

• TypeScript
• Go
• C#
• Java
• Rust

Contributing

Please ensure all implementations pass the shared test vectors before submitting changes.