Erlang/OTP Meets Dependent Types

Talk given at Erlang Workshop 2015, September 2015.

Extended Abstract (for ICFP Student Research Competition): http://lenary.co.uk/publications/erlang_deptypes_src/

My Dissertation: http://lenary.co.uk/publications/dissertation/

Transcript

1. Erlang/OTP Meets Dependent Types
   Archibald Samuel Elliott Edwin Brady
   University of St Andrews
   Erlang Workshop, 4 September 2015
   

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2. Introduction Compiler Concurrency OTP Conclusion
   Archibald Samuel Elliott, Edwin Brady Erlang/OTP Meets Dependent Types
   

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3. Introduction Compiler Concurrency OTP Conclusion
   Dependent Types
   • Types are Values
   • Values are Types
   • Programs and Proofs
   Archibald Samuel Elliott, Edwin Brady Erlang/OTP Meets Dependent Types
   

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4. Introduction Compiler Concurrency OTP Conclusion
   Compiler
   Archibald Samuel Elliott, Edwin Brady Erlang/OTP Meets Dependent Types
   

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5. Introduction Compiler Concurrency OTP Conclusion
   Actors
   data Actor : Type → Type → Type
   action : Actor interface term
   recieve : Actor i i
   spawn : (Actor i a) → IO (ActorID i)
   data ActorID : Type → Type
   pid : ActorID i
   send : ActorID i → i → IO ()
   Archibald Samuel Elliott, Edwin Brady Erlang/OTP Meets Dependent Types
   

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6. Introduction Compiler Concurrency OTP Conclusion
   -type lock_req () :: lock | unlock.
   -type lock_lock_resp () :: grant | wait.
   -type lock_resp () :: lock_lock_resp () | ok.
   -type lock_st () :: locked | unlocked.
   -spec handle_call(lock_req (), term(), lock_st ())
   → {ok , lock_resp (), lock_st ()} | error ().
   handle_call(lock , _, locked) → {ok , wait , locked};
   handle_call(lock , _, unlocked) → {ok , grant , locked};
   handle_call(unlock , _, locked) → {ok , ok , unlocked};
   handle_call(unlock , _, unlocked) → {ok , ok , unlocked}.
   Archibald Samuel Elliott, Edwin Brady Erlang/OTP Meets Dependent Types
   

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7. Introduction Compiler Concurrency OTP Conclusion
   Request Response
   data ReqResI : (r : Type)
   → (r → Type) → Type
   data ReqResId : ReqResI r f → Type
   req : {i : ReqResI r f}
   → ReqResId i
   → (m : r) → IO (f m)
   spawn : {i : ReqResI r f}
   → ((m : r) → f m)
   → IO (ReqResId i)
   Archibald Samuel Elliott, Edwin Brady Erlang/OTP Meets Dependent Types
   

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8. Introduction Compiler Concurrency OTP Conclusion
   data LockReq = Lock | Unlock
   data LockLockResp = Grant | Wait
   total
   LockResp : LockReq → Type
   LockResp Lock = LockLockResp
   LockResp Unlock = Unit
   LockI : ReqResI LockReq LockResp
   total
   lock_srv : (r : LockReq) → LockResp r
   lock_srv Lock = Wait
   lock_srv Unlock = ()
   spawn lock_srv : IO (ReqResId LockI)
   lock_pid : ReqResId LockI
   req lock_pid Lock : LockLockResp
   req lock_pid Unlock : Unit
   Archibald Samuel Elliott, Edwin Brady Erlang/OTP Meets Dependent Types
   

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9. Introduction Compiler Concurrency OTP Conclusion
   Behaviours
   • gen server
   • gen fsm
   • gen event
   Archibald Samuel Elliott, Edwin Brady Erlang/OTP Meets Dependent Types
   

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10. Introduction Compiler Concurrency OTP Conclusion
    Conclusion
    • We can produce verified concurrent programs in Idris
    • We can compile these programs to work with Erlang
    • We can run verified programs in Erlang
    Archibald Samuel Elliott, Edwin Brady Erlang/OTP Meets Dependent Types
    

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11. Introduction Compiler Concurrency OTP Conclusion
    Any Questions?
    Archibald Samuel Elliott, Edwin Brady Erlang/OTP Meets Dependent Types
    

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