Urbit Developers
  • Hoon

    • Overview
    • Cheat Sheet
    • Irregular forms
    • Hoon Errors
    • Hoon Style Guide
    • Basic Types
    • Advanced Types
    • Auras
    • Arvo
    • Standard Library

      • 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: Molds and mold builders
      • 5f: Profiling support
      • Runes

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

          • Limbs
          • Wings
          • Zuse

            • 2d(1-5): To JSON, Wains
            • 2d(6): From JSON
            • 2d(7): From JSON (unit)
            • 2e(2-3): Print & Parse JSON
            • 2m: Ordered Maps
          • Arvo

            • Overview
            • Ames

              • Overview
              • Cryptography
              • API Reference
              • Scry Reference
              • Data Types
              • Behn

                • Overview
                • API Reference
                • Scry Reference
                • Examples
                • Clay

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

                    • Overview
                    • Writing Marks
                    • Using Marks
                    • Examples
                  • Dill

                    • Overview
                    • API Reference
                    • Scry Reference
                    • Data Types
                    • Eyre

                      • Overview
                      • External API Reference
                      • Internal API Reference
                      • Scry Reference
                      • Data Types
                      • Guide
                      • Gall

                        • Overview
                        • API Reference
                        • Scry Reference
                        • Data Types
                        • Iris

                          • Overview
                          • API Reference
                          • Data Types
                          • Example
                          • Jael

                            • Overview
                            • API Reference
                            • Scry Reference
                            • Data Types
                            • Examples
                            • Khan

                              • Overview
                              • API Reference
                              • Data Types
                              • Example
                              • Threads

                                • Overview
                                • HTTP API
                                • Reference
                                • Strandio
                                • Gall

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

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

                                    • Scries
                                    • Subscriptions
                                    • Tutorials

                                      • Move Trace
                                      • Reference

                                        • Cryptography
                                        • Filesystem Hierarchy
                                      • 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
                                            • Urbit HD Wallet
                                            • Azimuth Data Flow
                                            • Azimuth.eth
                                            • Ecliptic.eth
                                            • Advanced Azimuth Tools
                                            • Life and Rift
                                            • Layer 2

                                              • Layer 2 Overview
                                              • Layer 2 Actions
                                              • Transaction Format
                                              • Rollers
                                              • Roller HTTP RPC-API
                                              • Custom Roller Tutorial
                                            • Glossary

                                              • Agent
                                              • Ames
                                              • API
                                              • Aqua
                                              • Arm
                                              • Arvo
                                              • Atom
                                              • Aura
                                              • Aural ASCII
                                              • Azimuth
                                              • Battery
                                              • Behn
                                              • Bowl
                                              • Bridge
                                              • Bunt
                                              • Card
                                              • Case
                                              • Cask
                                              • Cell
                                              • Censures
                                              • Claims
                                              • Clay
                                              • Cold atom
                                              • Comet
                                              • Commit
                                              • Cons
                                              • Context
                                              • Cord
                                              • Core
                                              • Delegated Sending
                                              • Desk
                                              • Dill
                                              • Document Proposal
                                              • Dojo
                                              • Door
                                              • Double-boot
                                              • Dry Gate
                                              • Duct
                                              • Ecliptic
                                              • Entropy
                                              • Event Log
                                              • Eyre
                                              • Face
                                              • Fact
                                              • Foo Bar Baz
                                              • Galaxy
                                              • Gall
                                              • Garden
                                              • Gate
                                              • Generator
                                              • Gift
                                              • Glob
                                              • HD Wallet
                                              • Helm
                                              • Hood
                                              • Hoon
                                              • Invite Tree
                                              • Iris
                                              • Jael
                                              • Jet
                                              • Kelvin versioning
                                              • Kernel
                                              • Keyfile
                                              • Keywords
                                              • Khan
                                              • Kiln
                                              • Landscape
                                              • Leg
                                              • List
                                              • Loobean
                                              • Lull
                                              • Mark
                                              • Metals
                                              • Mold
                                              • Monad
                                              • Moon
                                              • Move
                                              • Nock
                                              • Noun
                                              • ~
                                              • OTA Updates
                                              • Path Prefix
                                              • Path
                                              • @p
                                              • Payload
                                              • Peek
                                              • pH
                                              • Pier
                                              • Pill
                                              • Planet
                                              • Poke
                                              • Proxies
                                              • Scry
                                              • Replay
                                              • Factory Reset
                                              • Roller
                                              • Naive rollups
                                              • Rune
                                              • Runtime
                                              • Sail
                                              • Sample
                                              • Scry
                                              • Senate
                                              • Ship
                                              • Slam
                                              • Spider
                                              • Sponsor
                                              • Star
                                              • String
                                              • Subject Oriented Programming
                                              • Subject
                                              • Subscription
                                              • Tape
                                              • Thread
                                              • Trap
                                              • Udon
                                              • Upgrade Proposal
                                              • Userspace
                                              • Vane
                                              • Vase
                                              • Vere
                                              • Voting
                                              • Warm atom
                                              • Wet Gate
                                              • Wing
                                              • Wire
                                              • Wrapper
                                              • ~zod
                                              • Zuse
                                              • Additional

                                                • Cryptography
                                                • Mips (Maps of Maps)
                                                • Software Distribution

                                                  • Overview
                                                  • Docket File
                                                  • Glob
                                                  • Docs App

                                                    • Overview
                                                    • File Format
                                                    • Index File
                                                    • Suggested Structure
                                                  Urbit Developers
                                                  • Hoon

                                                    • Overview
                                                    • Cheat Sheet
                                                    • Irregular forms
                                                    • Hoon Errors
                                                    • Hoon Style Guide
                                                    • Basic Types
                                                    • Advanced Types
                                                    • Auras
                                                    • Arvo
                                                    • Standard Library

                                                      • 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: Molds and mold builders
                                                      • 5f: Profiling support
                                                      • Runes

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

                                                          • Limbs
                                                          • Wings
                                                          • Zuse

                                                            • 2d(1-5): To JSON, Wains
                                                            • 2d(6): From JSON
                                                            • 2d(7): From JSON (unit)
                                                            • 2e(2-3): Print & Parse JSON
                                                            • 2m: Ordered Maps
                                                          • Arvo

                                                            • Overview
                                                            • Ames

                                                              • Overview
                                                              • Cryptography
                                                              • API Reference
                                                              • Scry Reference
                                                              • Data Types
                                                              • Behn

                                                                • Overview
                                                                • API Reference
                                                                • Scry Reference
                                                                • Examples
                                                                • Clay

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

                                                                    • Overview
                                                                    • Writing Marks
                                                                    • Using Marks
                                                                    • Examples
                                                                  • Dill

                                                                    • Overview
                                                                    • API Reference
                                                                    • Scry Reference
                                                                    • Data Types
                                                                    • Eyre

                                                                      • Overview
                                                                      • External API Reference
                                                                      • Internal API Reference
                                                                      • Scry Reference
                                                                      • Data Types
                                                                      • Guide
                                                                      • Gall

                                                                        • Overview
                                                                        • API Reference
                                                                        • Scry Reference
                                                                        • Data Types
                                                                        • Iris

                                                                          • Overview
                                                                          • API Reference
                                                                          • Data Types
                                                                          • Example
                                                                          • Jael

                                                                            • Overview
                                                                            • API Reference
                                                                            • Scry Reference
                                                                            • Data Types
                                                                            • Examples
                                                                            • Khan

                                                                              • Overview
                                                                              • API Reference
                                                                              • Data Types
                                                                              • Example
                                                                              • Threads

                                                                                • Overview
                                                                                • HTTP API
                                                                                • Reference
                                                                                • Strandio
                                                                                • Gall

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

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

                                                                                    • Scries
                                                                                    • Subscriptions
                                                                                    • Tutorials

                                                                                      • Move Trace
                                                                                      • Reference

                                                                                        • Cryptography
                                                                                        • Filesystem Hierarchy
                                                                                      • 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
                                                                                            • Urbit HD Wallet
                                                                                            • Azimuth Data Flow
                                                                                            • Azimuth.eth
                                                                                            • Ecliptic.eth
                                                                                            • Advanced Azimuth Tools
                                                                                            • Life and Rift
                                                                                            • Layer 2

                                                                                              • Layer 2 Overview
                                                                                              • Layer 2 Actions
                                                                                              • Transaction Format
                                                                                              • Rollers
                                                                                              • Roller HTTP RPC-API
                                                                                              • Custom Roller Tutorial
                                                                                            • Glossary

                                                                                              • Agent
                                                                                              • Ames
                                                                                              • API
                                                                                              • Aqua
                                                                                              • Arm
                                                                                              • Arvo
                                                                                              • Atom
                                                                                              • Aura
                                                                                              • Aural ASCII
                                                                                              • Azimuth
                                                                                              • Battery
                                                                                              • Behn
                                                                                              • Bowl
                                                                                              • Bridge
                                                                                              • Bunt
                                                                                              • Card
                                                                                              • Case
                                                                                              • Cask
                                                                                              • Cell
                                                                                              • Censures
                                                                                              • Claims
                                                                                              • Clay
                                                                                              • Cold atom
                                                                                              • Comet
                                                                                              • Commit
                                                                                              • Cons
                                                                                              • Context
                                                                                              • Cord
                                                                                              • Core
                                                                                              • Delegated Sending
                                                                                              • Desk
                                                                                              • Dill
                                                                                              • Document Proposal
                                                                                              • Dojo
                                                                                              • Door
                                                                                              • Double-boot
                                                                                              • Dry Gate
                                                                                              • Duct
                                                                                              • Ecliptic
                                                                                              • Entropy
                                                                                              • Event Log
                                                                                              • Eyre
                                                                                              • Face
                                                                                              • Fact
                                                                                              • Foo Bar Baz
                                                                                              • Galaxy
                                                                                              • Gall
                                                                                              • Garden
                                                                                              • Gate
                                                                                              • Generator
                                                                                              • Gift
                                                                                              • Glob
                                                                                              • HD Wallet
                                                                                              • Helm
                                                                                              • Hood
                                                                                              • Hoon
                                                                                              • Invite Tree
                                                                                              • Iris
                                                                                              • Jael
                                                                                              • Jet
                                                                                              • Kelvin versioning
                                                                                              • Kernel
                                                                                              • Keyfile
                                                                                              • Keywords
                                                                                              • Khan
                                                                                              • Kiln
                                                                                              • Landscape
                                                                                              • Leg
                                                                                              • List
                                                                                              • Loobean
                                                                                              • Lull
                                                                                              • Mark
                                                                                              • Metals
                                                                                              • Mold
                                                                                              • Monad
                                                                                              • Moon
                                                                                              • Move
                                                                                              • Nock
                                                                                              • Noun
                                                                                              • ~
                                                                                              • OTA Updates
                                                                                              • Path Prefix
                                                                                              • Path
                                                                                              • @p
                                                                                              • Payload
                                                                                              • Peek
                                                                                              • pH
                                                                                              • Pier
                                                                                              • Pill
                                                                                              • Planet
                                                                                              • Poke
                                                                                              • Proxies
                                                                                              • Scry
                                                                                              • Replay
                                                                                              • Factory Reset
                                                                                              • Roller
                                                                                              • Naive rollups
                                                                                              • Rune
                                                                                              • Runtime
                                                                                              • Sail
                                                                                              • Sample
                                                                                              • Scry
                                                                                              • Senate
                                                                                              • Ship
                                                                                              • Slam
                                                                                              • Spider
                                                                                              • Sponsor
                                                                                              • Star
                                                                                              • String
                                                                                              • Subject Oriented Programming
                                                                                              • Subject
                                                                                              • Subscription
                                                                                              • Tape
                                                                                              • Thread
                                                                                              • Trap
                                                                                              • Udon
                                                                                              • Upgrade Proposal
                                                                                              • Userspace
                                                                                              • Vane
                                                                                              • Vase
                                                                                              • Vere
                                                                                              • Voting
                                                                                              • Warm atom
                                                                                              • Wet Gate
                                                                                              • Wing
                                                                                              • Wire
                                                                                              • Wrapper
                                                                                              • ~zod
                                                                                              • Zuse
                                                                                              • Additional

                                                                                                • Cryptography
                                                                                                • Mips (Maps of Maps)
                                                                                                • Software Distribution

                                                                                                  • Overview
                                                                                                  • Docket File
                                                                                                  • Glob
                                                                                                  • Docs App

                                                                                                    • Overview
                                                                                                    • File Format
                                                                                                    • Index File
                                                                                                    • Suggested Structure
                                                                                                  Reference/Hoon/Runes

                                                                                                  --, == Terminators

                                                                                                  The -- and == are used as terminators: -- for core expressions, and == for terminating a 'running' or 'jogging' series of Hoon expressions.

                                                                                                  -- "hephep"

                                                                                                  Syntax

                                                                                                  The -- rune is used to indicate the end of a core expression.

                                                                                                  Discussion

                                                                                                  The |%, |_, and |^ runes are used to create cores that can have arbitrarily many arms. When you have defined all the desired arms in a core expression (using the ++, +$, and +* runes), use -- to terminate the expression.

                                                                                                  Examples

                                                                                                  > =num |%
                                                                                                  ++ two 2
                                                                                                  ++ add-two |=(a=@ (add 2 a))
                                                                                                  ++ double |=(a=@ (mul 2 a))
                                                                                                  --
                                                                                                  > two.num
                                                                                                  2
                                                                                                  > (add-two.num 12)
                                                                                                  14
                                                                                                  > (double.num 12)
                                                                                                  24

                                                                                                  == "tistis"

                                                                                                  Syntax

                                                                                                  The == rune is used to indicate the end of a 'jogging' or 'running' series of Hoon expressions (runes that take a variable number of arguments).

                                                                                                  Discussion

                                                                                                  Certain runes are used to create expressions that may include arbitrarily many subexpressions. Such expressions are terminated with the == rune. For example, the :* and :~ runes are used to create a cell of any length. (The latter is just like the former except that it adds a null value at the end of the cell.) For another example, the %= rune used used to make arbitrarily many changes to a given wing value.

                                                                                                  Examples

                                                                                                  > :* 2
                                                                                                  3
                                                                                                  4
                                                                                                  5
                                                                                                  6
                                                                                                  ==
                                                                                                  [2 3 4 5 6]
                                                                                                  > :~ 2
                                                                                                  3
                                                                                                  4
                                                                                                  5
                                                                                                  6
                                                                                                  ==
                                                                                                  [2 3 4 5 6 ~]
                                                                                                  > =values [a=12 b=14 c=16 d=18 e=20]
                                                                                                  > %= values
                                                                                                  a 13
                                                                                                  b 15
                                                                                                  c 17
                                                                                                  d 19
                                                                                                  e 21
                                                                                                  ==
                                                                                                  [a=13 b=15 c=17 d=19 e=21]

                                                                                                  <-

                                                                                                  ! zap · Wild

                                                                                                  Edit this page on GitHub

                                                                                                  Last modified August 30, 2023