Urbit
  • Introduction
  • Development

    • Getting Started
    • Environment Setup
    • Grants Program
    • Project Repositories
    • Precepts
    • System Overview

      • Arvo
      • Hoon
      • Nock
      • Vere
      • Azimuth
      • Cryptography
      • Arvo

        • Overview
        • Reference

          • Cryptography
          • Filesystem Hierarchy
          • Ames

            • Overview
            • Cryptography
            • API Reference
            • Behn

              • Overview
              • API Reference
              • Clay

                • Overview
                • Architecture
                • Using Clay
                • Data Types
                • Scry Reference
                • API Reference
                • Examples
                • Dill

                  • Overview
                  • API Reference
                  • Eyre

                    • Overview
                    • External API Reference
                    • Internal API Reference
                    • Scry Reference
                    • Data Types
                    • Examples
                    • Ford

                      • Overview
                      • Gall

                        • Overview
                        • Iris

                          • API Reference
                          • Jael

                            • API Reference
                            • Concepts

                              • Subscriptions
                              • Tutorials

                                • Move Trace
                              • Userspace

                                • Overview
                                • Gall

                                  • Overview
                                  • Tutorial
                                  • API Reference
                                  • Graph Store

                                    • Graph Store Overview
                                    • Data Structure Overview
                                    • Validator Walkthrough
                                    • Advanced Info
                                    • Threads

                                      • Overview
                                      • HTTP API
                                      • Reference
                                      • Basics

                                        • Fundamentals
                                        • Bind
                                        • Input
                                        • Output
                                        • Summary
                                        • Gall

                                          • Start Thread
                                          • Take Result
                                          • Take Facts
                                          • Stop Thread
                                          • Poke Thread
                                          • Examples

                                            • Fetch JSON
                                            • Child Thread
                                            • Main-loop
                                            • Poke Agent
                                            • Scry
                                            • Take Fact
                                          • Landscape

                                            • Overview
                                            • API Reference

                                              • Graph Store
                                          • Hoon

                                            • Overview
                                            • Hoon School

                                              • 1.1 Setup
                                              • 1.1.1 Walkthrough: List of Numbers
                                              • 1.2 Nouns
                                              • 1.3 Hoon Syntax
                                              • 1.3.1 Walkthrough: Conditionals
                                              • 1.4 Gates (Hoon Functions)
                                              • 1.4.1 Walkthrough: Recursion
                                              • 1.5 Lists
                                              • 1.5.1 Walkthrough: Fibonacci Sequence
                                              • 1.6 The Subject and Its Legs
                                              • 1.6.1 Walkthrough: Ackermann Function
                                              • 1.7 Arms and Cores
                                              • 1.7.1 Walkthrough: Caesar Cipher
                                              • 1.8 Doors
                                              • 1.8.1 Bank Account
                                              • 1.9 Generators
                                              • 2.1 Atoms, Auras, and Simple Cell Types
                                              • 2.2 Type Checking and Type Inference
                                              • 2.3 Structures and Complex Types
                                              • 2.3.1 Walkthrough: Libraries
                                              • 2.3.2 Molds
                                              • 2.4 Standard Library: Trees, Sets, and Maps
                                              • 2.5 Type Polymorphism
                                              • 2.5.1 Walkthrough: Iron Polymorphism and Wet Polymorphism
                                              • 2.5.2 Walkthrough: Lead Polymorphism
                                              • 2.6 Behn
                                              • 2.7 Gall
                                              • 2.7.1 Gall Walkthrough: Egg Timer
                                              • Guides

                                                • CLI apps
                                                • Parsing
                                                • Writing Aqua Tests
                                                • Reference

                                                  • Cheat Sheet
                                                  • Irregular forms
                                                  • Hoon Errors
                                                  • Hoon Style Guide
                                                  • Basic Types
                                                  • Advanced Types
                                                  • Auras
                                                  • Runes

                                                    • Atoms and strings
                                                    • Nock . ('dot')
                                                    • Wild ! ('zap')
                                                    • Change Subject = ('tis')
                                                    • Conditionals ? ('wut')
                                                    • Cores | ('bar')
                                                    • Arms + ('lus')
                                                    • Cells : ('col')
                                                    • Calls % ('cen')
                                                    • Casts ^ ('ket')
                                                    • Structures $ ('buc')
                                                    • Make ; ('mic')
                                                    • Hints ~ ('sig')
                                                    • Terminators -- and ==
                                                    • Limbs and wings

                                                      • Limbs
                                                      • Wings
                                                      • Standard library

                                                        • Table of Contents
                                                        • 1a: Basic Arithmetic
                                                        • 1b: Tree Addressing
                                                        • 1c: Molds and Mold-Builders
                                                        • 2a: Unit Logic
                                                        • 2b: List Logic
                                                        • 2c: Bit Arithmetic
                                                        • 2d: Bit Logic
                                                        • 2e: Insecure Hashing
                                                        • 2f: Noun Ordering
                                                        • 2g: Unsigned Powers
                                                        • 2h: Set Logic
                                                        • 2i: Map Logic
                                                        • 2j: Jar and Jug Logic
                                                        • 2k: Queue Logic
                                                        • 2l: Container from Container
                                                        • 2m: Container from Noun
                                                        • 2n: Functional Hacks
                                                        • 2o: Normalizing Containers
                                                        • 2p: Serialization
                                                        • 2q: Molds and Mold-Builders
                                                        • 3a: Modular and Signed Ints
                                                        • 3b: Floating Point
                                                        • 3c: Urbit Time
                                                        • 3d: SHA Hash Family
                                                        • 3e: AES encryption (Removed)
                                                        • 3f: Scrambling
                                                        • 3g: Molds and Mold-Builders
                                                        • 4a: Exotic Bases
                                                        • 4b: Text Processing
                                                        • 4c: Tank Printer
                                                        • 4d: Parsing (Tracing)
                                                        • 4e: Parsing (Combinators)
                                                        • 4f: Parsing (Rule-Builders)
                                                        • 4g: Parsing (Outside Caller)
                                                        • 4h: Parsing (ASCII Glyphs)
                                                        • 4i: Parsing (Useful Idioms)
                                                        • 4j: Parsing (Bases and Base Digits)
                                                        • 4k: Atom Printing
                                                        • 4l: Atom Parsing
                                                        • 4m: Formatting Functions
                                                        • 4n: Virtualization
                                                        • 4o: Molds
                                                        • 5a: Compiler Utilities
                                                        • 5b: Macro Expansion
                                                        • 5c: Compiler Backend & Prettyprinter
                                                        • 5d: Parser
                                                        • 5e: Caching Compiler
                                                        • 5f: Molds and Mold-Builders
                                                        • 5g: profiling support
                                                    • Nock

                                                      • Nock Definition
                                                      • Explanation
                                                      • Example
                                                      • Implementations
                                                      • Vere

                                                        • C Runtime System
                                                        • Land of Nouns
                                                        • API overview by prefix
                                                        • C in Urbit
                                                        • Writing Jets
                                                        • Cryptography
                                                        • Azimuth

                                                          • Overview
                                                          • Life and Rift
                                                          • Advanced Azimuth Tools
                                                          • Glossary

                                                            • Ames
                                                            • Aqua
                                                            • Arm
                                                            • Arvo
                                                            • Atom
                                                            • Azimuth
                                                            • Battery
                                                            • Behn
                                                            • Breach
                                                            • Bridge
                                                            • Censures
                                                            • Ceremony
                                                            • chat
                                                            • Claims
                                                            • Clay
                                                            • Comet
                                                            • Core
                                                            • Delegated Sending
                                                            • Desk
                                                            • Dill
                                                            • Document Proposal
                                                            • Dojo
                                                            • Door
                                                            • Ecliptic
                                                            • Event Log
                                                            • Eyre
                                                            • Ford
                                                            • Galaxy
                                                            • Gall
                                                            • Gate
                                                            • HD Wallet
                                                            • Hoon
                                                            • Invite Tree
                                                            • Iris
                                                            • Jael
                                                            • Jaque
                                                            • Keyfile
                                                            • Landscape
                                                            • Mark
                                                            • Moon
                                                            • Nock
                                                            • Noun
                                                            • OTA Updates
                                                            • Payload
                                                            • pH
                                                            • Pier
                                                            • Pill
                                                            • Planet
                                                            • Proxies
                                                            • Replay
                                                            • Sail/Udon
                                                            • Senate
                                                            • Ship
                                                            • ship.arvo.network
                                                            • Star
                                                            • |sync
                                                            • Trap
                                                            • Upgrade Proposal
                                                            • Vane
                                                            • Vere
                                                            • Voting
                                                            • Wallet-Generator
                                                            Urbit
                                                            • Introduction
                                                            • Development

                                                              • Getting Started
                                                              • Environment Setup
                                                              • Grants Program
                                                              • Project Repositories
                                                              • Precepts
                                                              • System Overview

                                                                • Arvo
                                                                • Hoon
                                                                • Nock
                                                                • Vere
                                                                • Azimuth
                                                                • Cryptography
                                                                • Arvo

                                                                  • Overview
                                                                  • Reference

                                                                    • Cryptography
                                                                    • Filesystem Hierarchy
                                                                    • Ames

                                                                      • Overview
                                                                      • Cryptography
                                                                      • API Reference
                                                                      • Behn

                                                                        • Overview
                                                                        • API Reference
                                                                        • Clay

                                                                          • Overview
                                                                          • Architecture
                                                                          • Using Clay
                                                                          • Data Types
                                                                          • Scry Reference
                                                                          • API Reference
                                                                          • Examples
                                                                          • Dill

                                                                            • Overview
                                                                            • API Reference
                                                                            • Eyre

                                                                              • Overview
                                                                              • External API Reference
                                                                              • Internal API Reference
                                                                              • Scry Reference
                                                                              • Data Types
                                                                              • Examples
                                                                              • Ford

                                                                                • Overview
                                                                                • Gall

                                                                                  • Overview
                                                                                  • Iris

                                                                                    • API Reference
                                                                                    • Jael

                                                                                      • API Reference
                                                                                      • Concepts

                                                                                        • Subscriptions
                                                                                        • Tutorials

                                                                                          • Move Trace
                                                                                        • Userspace

                                                                                          • Overview
                                                                                          • Gall

                                                                                            • Overview
                                                                                            • Tutorial
                                                                                            • API Reference
                                                                                            • Graph Store

                                                                                              • Graph Store Overview
                                                                                              • Data Structure Overview
                                                                                              • Validator Walkthrough
                                                                                              • Advanced Info
                                                                                              • Threads

                                                                                                • Overview
                                                                                                • HTTP API
                                                                                                • Reference
                                                                                                • Basics

                                                                                                  • Fundamentals
                                                                                                  • Bind
                                                                                                  • Input
                                                                                                  • Output
                                                                                                  • Summary
                                                                                                  • Gall

                                                                                                    • Start Thread
                                                                                                    • Take Result
                                                                                                    • Take Facts
                                                                                                    • Stop Thread
                                                                                                    • Poke Thread
                                                                                                    • Examples

                                                                                                      • Fetch JSON
                                                                                                      • Child Thread
                                                                                                      • Main-loop
                                                                                                      • Poke Agent
                                                                                                      • Scry
                                                                                                      • Take Fact
                                                                                                    • Landscape

                                                                                                      • Overview
                                                                                                      • API Reference

                                                                                                        • Graph Store
                                                                                                    • Hoon

                                                                                                      • Overview
                                                                                                      • Hoon School

                                                                                                        • 1.1 Setup
                                                                                                        • 1.1.1 Walkthrough: List of Numbers
                                                                                                        • 1.2 Nouns
                                                                                                        • 1.3 Hoon Syntax
                                                                                                        • 1.3.1 Walkthrough: Conditionals
                                                                                                        • 1.4 Gates (Hoon Functions)
                                                                                                        • 1.4.1 Walkthrough: Recursion
                                                                                                        • 1.5 Lists
                                                                                                        • 1.5.1 Walkthrough: Fibonacci Sequence
                                                                                                        • 1.6 The Subject and Its Legs
                                                                                                        • 1.6.1 Walkthrough: Ackermann Function
                                                                                                        • 1.7 Arms and Cores
                                                                                                        • 1.7.1 Walkthrough: Caesar Cipher
                                                                                                        • 1.8 Doors
                                                                                                        • 1.8.1 Bank Account
                                                                                                        • 1.9 Generators
                                                                                                        • 2.1 Atoms, Auras, and Simple Cell Types
                                                                                                        • 2.2 Type Checking and Type Inference
                                                                                                        • 2.3 Structures and Complex Types
                                                                                                        • 2.3.1 Walkthrough: Libraries
                                                                                                        • 2.3.2 Molds
                                                                                                        • 2.4 Standard Library: Trees, Sets, and Maps
                                                                                                        • 2.5 Type Polymorphism
                                                                                                        • 2.5.1 Walkthrough: Iron Polymorphism and Wet Polymorphism
                                                                                                        • 2.5.2 Walkthrough: Lead Polymorphism
                                                                                                        • 2.6 Behn
                                                                                                        • 2.7 Gall
                                                                                                        • 2.7.1 Gall Walkthrough: Egg Timer
                                                                                                        • Guides

                                                                                                          • CLI apps
                                                                                                          • Parsing
                                                                                                          • Writing Aqua Tests
                                                                                                          • Reference

                                                                                                            • Cheat Sheet
                                                                                                            • Irregular forms
                                                                                                            • Hoon Errors
                                                                                                            • Hoon Style Guide
                                                                                                            • Basic Types
                                                                                                            • Advanced Types
                                                                                                            • Auras
                                                                                                            • Runes

                                                                                                              • Atoms and strings
                                                                                                              • Nock . ('dot')
                                                                                                              • Wild ! ('zap')
                                                                                                              • Change Subject = ('tis')
                                                                                                              • Conditionals ? ('wut')
                                                                                                              • Cores | ('bar')
                                                                                                              • Arms + ('lus')
                                                                                                              • Cells : ('col')
                                                                                                              • Calls % ('cen')
                                                                                                              • Casts ^ ('ket')
                                                                                                              • Structures $ ('buc')
                                                                                                              • Make ; ('mic')
                                                                                                              • Hints ~ ('sig')
                                                                                                              • Terminators -- and ==
                                                                                                              • Limbs and wings

                                                                                                                • Limbs
                                                                                                                • Wings
                                                                                                                • Standard library

                                                                                                                  • Table of Contents
                                                                                                                  • 1a: Basic Arithmetic
                                                                                                                  • 1b: Tree Addressing
                                                                                                                  • 1c: Molds and Mold-Builders
                                                                                                                  • 2a: Unit Logic
                                                                                                                  • 2b: List Logic
                                                                                                                  • 2c: Bit Arithmetic
                                                                                                                  • 2d: Bit Logic
                                                                                                                  • 2e: Insecure Hashing
                                                                                                                  • 2f: Noun Ordering
                                                                                                                  • 2g: Unsigned Powers
                                                                                                                  • 2h: Set Logic
                                                                                                                  • 2i: Map Logic
                                                                                                                  • 2j: Jar and Jug Logic
                                                                                                                  • 2k: Queue Logic
                                                                                                                  • 2l: Container from Container
                                                                                                                  • 2m: Container from Noun
                                                                                                                  • 2n: Functional Hacks
                                                                                                                  • 2o: Normalizing Containers
                                                                                                                  • 2p: Serialization
                                                                                                                  • 2q: Molds and Mold-Builders
                                                                                                                  • 3a: Modular and Signed Ints
                                                                                                                  • 3b: Floating Point
                                                                                                                  • 3c: Urbit Time
                                                                                                                  • 3d: SHA Hash Family
                                                                                                                  • 3e: AES encryption (Removed)
                                                                                                                  • 3f: Scrambling
                                                                                                                  • 3g: Molds and Mold-Builders
                                                                                                                  • 4a: Exotic Bases
                                                                                                                  • 4b: Text Processing
                                                                                                                  • 4c: Tank Printer
                                                                                                                  • 4d: Parsing (Tracing)
                                                                                                                  • 4e: Parsing (Combinators)
                                                                                                                  • 4f: Parsing (Rule-Builders)
                                                                                                                  • 4g: Parsing (Outside Caller)
                                                                                                                  • 4h: Parsing (ASCII Glyphs)
                                                                                                                  • 4i: Parsing (Useful Idioms)
                                                                                                                  • 4j: Parsing (Bases and Base Digits)
                                                                                                                  • 4k: Atom Printing
                                                                                                                  • 4l: Atom Parsing
                                                                                                                  • 4m: Formatting Functions
                                                                                                                  • 4n: Virtualization
                                                                                                                  • 4o: Molds
                                                                                                                  • 5a: Compiler Utilities
                                                                                                                  • 5b: Macro Expansion
                                                                                                                  • 5c: Compiler Backend & Prettyprinter
                                                                                                                  • 5d: Parser
                                                                                                                  • 5e: Caching Compiler
                                                                                                                  • 5f: Molds and Mold-Builders
                                                                                                                  • 5g: profiling support
                                                                                                              • Nock

                                                                                                                • Nock Definition
                                                                                                                • Explanation
                                                                                                                • Example
                                                                                                                • Implementations
                                                                                                                • Vere

                                                                                                                  • C Runtime System
                                                                                                                  • Land of Nouns
                                                                                                                  • API overview by prefix
                                                                                                                  • C in Urbit
                                                                                                                  • Writing Jets
                                                                                                                  • Cryptography
                                                                                                                  • Azimuth

                                                                                                                    • Overview
                                                                                                                    • Life and Rift
                                                                                                                    • Advanced Azimuth Tools
                                                                                                                    • Glossary

                                                                                                                      • Ames
                                                                                                                      • Aqua
                                                                                                                      • Arm
                                                                                                                      • Arvo
                                                                                                                      • Atom
                                                                                                                      • Azimuth
                                                                                                                      • Battery
                                                                                                                      • Behn
                                                                                                                      • Breach
                                                                                                                      • Bridge
                                                                                                                      • Censures
                                                                                                                      • Ceremony
                                                                                                                      • chat
                                                                                                                      • Claims
                                                                                                                      • Clay
                                                                                                                      • Comet
                                                                                                                      • Core
                                                                                                                      • Delegated Sending
                                                                                                                      • Desk
                                                                                                                      • Dill
                                                                                                                      • Document Proposal
                                                                                                                      • Dojo
                                                                                                                      • Door
                                                                                                                      • Ecliptic
                                                                                                                      • Event Log
                                                                                                                      • Eyre
                                                                                                                      • Ford
                                                                                                                      • Galaxy
                                                                                                                      • Gall
                                                                                                                      • Gate
                                                                                                                      • HD Wallet
                                                                                                                      • Hoon
                                                                                                                      • Invite Tree
                                                                                                                      • Iris
                                                                                                                      • Jael
                                                                                                                      • Jaque
                                                                                                                      • Keyfile
                                                                                                                      • Landscape
                                                                                                                      • Mark
                                                                                                                      • Moon
                                                                                                                      • Nock
                                                                                                                      • Noun
                                                                                                                      • OTA Updates
                                                                                                                      • Payload
                                                                                                                      • pH
                                                                                                                      • Pier
                                                                                                                      • Pill
                                                                                                                      • Planet
                                                                                                                      • Proxies
                                                                                                                      • Replay
                                                                                                                      • Sail/Udon
                                                                                                                      • Senate
                                                                                                                      • Ship
                                                                                                                      • ship.arvo.network
                                                                                                                      • Star
                                                                                                                      • |sync
                                                                                                                      • Trap
                                                                                                                      • Upgrade Proposal
                                                                                                                      • Vane
                                                                                                                      • Vere
                                                                                                                      • Voting
                                                                                                                      • Wallet-Generator
                                                                                                                      Urbit/Documentation/System Overview

                                                                                                                      Hoon

                                                                                                                      Hoon is a strictly typed functional programming language that compiles itself to Nock and is designed to support higher-order functional programming without requiring knowledge of category theory or other advanced mathematics. Haskell is fun but it isn't for everybody.

                                                                                                                      Hoon aspires to a concrete, imperative feel. To discourage the creation of write-only code, Hoon forbids user-level macros and uses ASCII digraphs instead of keywords. The type system infers only forward and does not use unification, but is not much weaker than Haskell's. The compiler and inference engine is about 3000 lines of Hoon.

                                                                                                                      Further Reading

                                                                                                                      • Hoon Overview: Learn why we created a new language to build Urbit in.
                                                                                                                      • Hoon School: A collection of tutorials designed to teach you the Hoon language.
                                                                                                                      • Guides: Guides to specific Hoon tasks,

                                                                                                                      including testing, command-line interface apps, and parsing.

                                                                                                                      • Reference: Reference material primarily intended for Hoon developers with some experience.

                                                                                                                      <-

                                                                                                                      Arvo

                                                                                                                      Nock

                                                                                                                      ->