Exceptional asynchronous session types: session types without tiers

Session types statically guarantee that communication complies with a protocol. However, most accounts of session typing do not account for failure, which means they are of limited use in real applications---especially distributed applications---where failure is pervasive. We present the first forma...

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Bibliographic Details
Published in:Proceedings of ACM on programming languages Vol. 3; no. POPL; pp. 1 - 29
Main Authors: Fowler, Simon, Lindley, Sam, Morris, J. Garrett, Decova, Sára
Format: Journal Article
Language:English
Published: New York, NY, USA ACM 02.01.2019
Subjects:
Concurrent programming languages
Contextual software domains
Deadlocks
Functional languages
General programming languages
Language types
Operating systems
Process management
Software and its engineering
Software notations and tools
Software organization and properties
asynchrony
session types
exceptions
web programming
ISSN:2475-1421, 2475-1421
Online Access:Get full text
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Summary:Session types statically guarantee that communication complies with a protocol. However, most accounts of session typing do not account for failure, which means they are of limited use in real applications---especially distributed applications---where failure is pervasive. We present the first formal integration of asynchronous session types with exception handling in a functional programming language. We define a core calculus which satisfies preservation and progress properties, is deadlock free, confluent, and terminating. We provide the first implementation of session types with exception handling for a fully-fledged functional programming language, by extending the Links web programming language; our implementation draws on existing work on effect handlers. We illustrate our approach through a running example of two-factor authentication, and a larger example of a session-based chat application where communication occurs over session-typed channels and disconnections are handled gracefully.
ISSN:2475-1421
2475-1421
DOI:10.1145/3290341