Pony
ParadigmsActor model, object-oriented, imperative
DesignerSylvan Clebsch[1]
Released28 April 2015 (age 11)[2]
Latest release version0.62.1 (Beta)
Latest release dateMarch 28, 2026 (age 0)
Typingstrong, static, inferred, nominal, structural
Programming languageC
LicenseBSD 2-clause.[3]
Websitewww.ponylang.org
Influenced byE[4]
InfluencedProject Verona[5]

Pony (also known as ponylang) is a object-oriented, actor model, capabilities-secure, high performance programming language.[6][7] Pony's reference capabilities allow even mutable data to be safely passed by reference between actors. Garbage collection is performed concurrently, per-actor, which eliminates the need to pause program execution or "stop the world".[8][9][10] Sylvan Clebsch is the original creator of the language.[11][12] It is now being maintained and developed by members of the Pony team.[13] It is free and open-source software with a BSD 2-clause license.

History

The language was created by Sylvan Clebsch, while a PhD student at Imperial College London. His professor at that time was Sophia Drossopoulou, who is also well known for her contributions to computer programming, and as a lecturer. According to developers who have talked to Sylvan, he was frustrated with not having a high performance language that could run concurrent code securely, safely, and more simply.[14]

Language design

At its core, Pony is a systems language designed around safety and performance.

Safety

  • Type safety – Pony is a type safe language.[15]
  • Memory safety – There are no dangling pointers and no buffer overruns. There is no null but optional types can be safely represented using unions with the None type.[6][16]
  • Exception safety – There are no runtime exceptions. All exceptions have defined semantics and are always caught.[17]
  • Concurrency safety – The type system employs reference capabilities to ensure (at compile time) that there are no data races nor deadlocks.[18][19][20][21]

Performance

  • Lock-free – By design, Pony avoids the need for traditional locking mechanisms, which eliminates the overhead and contention associated with locks.[14]
  • Native code – Pony is an ahead-of-time compiled language. There is no interpreter or virtual machine[18][16]
  • Concurrent garbage collection – Each actor's heap is collected separately and concurrently, avoiding the need to "stop the world" for global collection.[11][12][21]

Examples

Hello, World

In Pony, instead of a main function, there is a main actor. The creation of this actor serves as the entry point into a Pony program, as in this "Hello, World!" program.[6][17]

actor Main
  new create(env: Env) =>
    env.out.print("Hello, world!")

There are no global variables in Pony, meaning everything must be contained within an instance of a class or an actor.[14] As such, even the environment that allows for printing to standard output is passed as a parameter.[14][6]

References

  1. ^ "Sylvan Clebsch". ACM
  2. ^ "First public release". GitHub. 28 April 2015.
  3. ^ "Ponyc/LICENSE at main: ponylang/Ponyc". GitHub
  4. ^ Daniele BonettaLuca; Svizzera italiana; Stefan Marr; Walter Binder (2 November 2016). "GEMS: Shared-Memory Parallel Programming for Node.js". oracle. Retrieved 10 March 2025. Pony is itself inspired by the design of E's programming model
  5. ^ Liam Tung. "Microsoft opens up Rust-inspired Project Verona programming language on GitHub". ZDNet "Project Verona, which also borrows concepts from Cyclone, a "safe dialect of C" and Pony, which has key contributors from Microsoft Research"
  6. ^ Allen 2024.
  7. ^ "Introduction to Actor Model". adabeat. 8 August 2024. Retrieved 8 March 2025.
  8. ^ Sylvan Clebsch; Juliana Franco; Sophia Drossopoulou (12 October 2017). "Ownership and Reference Counting Based Garbage Collection in the Actor World". Proc. ACM Program. Lang.. 1 (OOPSLA): 72:1–72:28. doi:10.1145/3133896. Retrieved 24 December 2024.
  9. ^ "Introduction to the Pony Programming Language". LinkedIn. Society 5 Solutions. 15 October 2024. Retrieved 28 December 2024.
  10. ^ Daniel Caccamo (2018). "GoA: Actors with Locally Managed Memory for Go". UWSpace. Retrieved 28 December 2024.
  11. ^ Charles Humble (14 March 2016). "Using the Actor-model Language Pony for FinTec". InfoQ. Retrieved 24 December 2024.
  12. ^ Sophia Drossopoulou (14 September 2020). "Pony, Actors, Causality, Types, and Garbage Collection". InfoQ. Retrieved 24 December 2024.
  13. ^ "Team Pony". GitHub. Retrieved 28 December 2024.
  14. ^ Kristoffer Grönlund (22 January 2018). "Everyone gets a pony!". archive. Linux Conference Australia 2018 (LCA2018). Retrieved 28 December 2024.
  15. ^ John Mumm (19 March 2019). "Safely Sharing Data: Reference Capabilities in Pony". codemotion. Retrieved 28 December 2024.
  16. ^ Ankush Thakur (21 December 2024). "12 New Programming Languages You Should Know". geekflare. Retrieved 3 January 2025.
  17. ^ MCStone 2023.
  18. ^ Mölle 2017.
  19. ^ Sean T Allen (30 May 2018). "Introduction to the Pony programming language". opensource. Retrieved 28 December 2024.
  20. ^ Sylvan Clebsch; Sophia Drossopoulou; Sebastian Blessing (October 2015). Deny capabilities for safe, fast actors. AGERE! 2015: Proceedings of the 5th International Workshop on Programming Based on Actors, Agents, and Decentralized Control. Elisa Gonzalez Boix, Philipp Haller, Alessandro Ricci, Carlos Varela (ed.). Pittsburgh, PA, USA: Association for Computing Machinery. pp. 1–12. doi:10.1145/2824815.2824816. ISBN 9781450339018.
  21. ^ Juliana Franco; Sylvain Clebsch; Sophia Drossopoulou; Jan Vitek; Tobias Wrigstad (9 March 2018). "Soundness of a Concurrent Collector for Actors". imperial. Retrieved 8 March 2025.

Further reading

  • Mölle, Andreas (Dec 2017). "Developing concurrent programs with Pony". Linux Magazine. ' (205). ISSN 1536-4674
  • MCStone, Maverick (Dec 2023). Pony Playbook: Mastering the Basics of Concurrent Programming. Independently Published. ISBN 979-8870768175.
  • Allen, Corby (Jul 2024). Pony Programming: The Complete Guide to Building High-Performance, Concurrent, and Secure Applications with Pony. Independently Published. ISBN 979-8332662072.