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I want a pony
The document presents Pony, an open-source, object-oriented programming language that utilizes the actor model for concurrent task execution, emphasizing capabilities-security and avoiding common concurrency issues like atomicity violations and deadlocks. It features a statically typed system with strong guarantees on concurrency patterns, high performance through LLVM, and various capabilities like reference capabilities for managing access to data. The author, Piotr Buda, outlines Pony's key features, such as classes, actors, and async message passing, while addressing the challenges of achieving correct concurrency in programming.
I want a pony
- 1. I WANT APONY! Object-oriented, capabilities-secure with actor model
- 2. ABOUT ME Piotr Buda@ So wareMill -http://github.com/pbuda http://www.So wareMill.com Twitter: @piotrbuda
- 3. CONCURRENCY Executing multiple tasks Disjointand overlapping Parallel and/or scheduled Executed in unknown order
- 4. WHY DO WENEED IT? Because code runs in parallel we can get: efficiency scalability
- 5. PROBLEMS we don't knowthe order of execution atomicity violation order violation deadlocks
- 6. HOW TO HANDLEBUGS? synchronization share nothing immutable state isolated state
- 7. SYNCHRONIZATION govern access toshared resource solves problems can lead to no concurrency at all
- 8. SHARE NOTHING perfectly concurrent scalesperfectly limited use
- 9. IMMUTABLE STATE data can'tchange can share global state can't migrate without copy doesn't work when you need to change state
- 10. ISOLATED STATE exclusive accessto state ony one task can change data sharing over time no concurrent access
- 11. MEET PONY Pony isan open-source, object-oriented, actor-model, capabilities-secure, high performance programming language. young (0.9.0 released on 11.11)
- 12. WHAT IS PONY? objectoriented actor model type-safe no runtime exceptions no locks
- 13. PONY LANGUAGE FEATURES classes,actors, primitives nominal and structural subtyping object literals and lambdas generics pattern matching C FFI per actor, concurrent garbage collection
- 14. PONY IS STATICALLYTYPED it can understand code type system makes guarantees enforces concurrency patterns high performance (llvm)
- 15. PONY IS ANACTOR MODEL uses actors to run asynchronous code passes messages, triggers behaviors causal message ordering actors are sequential themselves
- 16. CAPABILITIES A capability isan unforgeable token that (a) designates an object and (b) gives the program the authority to perform a specific set of actions on that object.
- 17. REFERENCE CAPABILITIES express accessrights to objects type qualifiers make concurrency safe
- 18. REFERENCE CAPABILITIES Cap Description refreference Normal data val value Immutable data box box Read-only to you iso isolated Isolated data trn transition Write-only to you tag tag Identification only
- 19. REFERENCE - REF noother variable can be used by other actors to read from or write to that object.
- 20. BOX no other variablecan be used by other actors to write to that object
- 21. TRANSITION - TRN noother variable can be used by any actor to write to that object, and no other variable can be used by other actors to read from or write to that object
- 22. VALUE - VAL noother variable can be used by any actor to write to that object.
- 23. ISOLATED STATE -ISO no other variable can be used by any actor to read from or write to that object
- 24. TAG makes no guaranteesabout other variables at all
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- 26. RECOVERING CAPABILITIES recovering lis reference capabilities of the result iso, trn, ref can become any val, box can become immutable or opaque
- 27. CAPABILITY ALIASING more thanone variable pointing to the same object iso > tag trn > box everything else as itself ephemereal types (iso^) alias types (iso!)
- 28. SUBTYPING sometimes we needto supply other types we need to make sure we can do that safely simple substitution aliased and ephemeral substitution
- 29. SUMMARY we want concurrencybut it's hard to do right Pony can help with that
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