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Jac Language Reference#

The AI-Native Full-Stack Programming Language

One Language for Backend, Frontend, and AI

How to Use This Reference#

This is a comprehensive reference for the Jac programming language. Navigate using the sidebar or use browser search (Ctrl+F / Cmd+F) within each page.

Conventions:

  • monospace -- Keywords, types, operators, and code
  • Bold -- Key terms and concepts
  • Code blocks are verified, executable examples
  • Sections marked (OSP) are Object-Spatial Programming features

Reference Sections#

Part I: Foundation#

Core language concepts and syntax basics.

  • Introduction
  • Getting Started
  • Language Basics
  • Types and Values
  • Variables and Scope
  • Operators
  • Control Flow

Part II: Functions and Objects#

Functions, classes, and object-oriented programming.

  • Functions and Abilities
  • Object-Oriented Programming
  • Implementations and Forward Declarations

Part III: Object-Spatial Programming#

Jac's unique graph-based programming paradigm.

  • Introduction to OSP
  • Nodes
  • Edges
  • Walkers
  • Graph Construction
  • Graph Traversal
  • Data Spatial Queries
  • Typed Context Blocks

Part IV: Full-Stack Development#

Building complete applications with Jac.

  • Module System
  • Server-Side Development
  • Client-Side Development (JSX)
  • Server-Client Communication
  • Authentication & Users
  • Memory & Persistence
  • Development Tools

Part V: AI Integration#

LLM integration and meaning-typed programming.

  • Meaning Typed Programming
  • Semantic Strings
  • The by Operator and LLM Delegation
  • Agentic AI Patterns

Part VI: Concurrency#

Async programming and parallel execution.

  • Async/Await
  • Concurrent Expressions

Part VII: Advanced Features#

Error handling, testing, and advanced operators.

  • Error Handling
  • Testing
  • Filter and Assign Comprehensions
  • Pipe Operators

Part VIII: Ecosystem#

Tools, plugins, and interoperability.

  • CLI Reference
  • Plugin System
  • Project Configuration
  • Python Interoperability
  • JavaScript/TypeScript Interoperability
  • Python Integration - 5 adoption patterns, transpilation details

Part IX: Deployment and Scaling#

Production deployment with jac-scale.

  • jac-scale Plugin
  • Kubernetes Deployment
  • Production Architecture
  • Library Mode - Pure Python with Jac runtime

Appendices#

Quick references and migration guides.

  • Complete Keyword Reference
  • Operator Quick Reference
  • Grammar Summary
  • Common Gotchas
  • Migration from Python
  • LLM Provider Reference

Quick Reference#

Focused reference pages for common patterns:

Tutorials#

Step-by-step guides for learning Jac:

Plugin References#

Detailed API documentation for plugins:

Other References#