We Know I Know You Know; Choreographic Programming With Multicast and Multiply Located Values
<|reference_start|>We Know I Know You Know; Choreographic Programming With Multicast and Multiply Located Values: Concurrent distributed systems are notoriously difficult to construct and reason about. Choreographic programming is a recent paradigm that describes a distributed system in a single global program called a choreography. Choreographies simplify reasoning about distributed systems and can ensure deadlock freedom by static analysis. In previous choreographic programming languages, each value is located at a single party, and the programmer is expected to insert special untyped "select" operations to ensure that all parties follow the same communication pattern.   We present He-Lambda-Small, a new choreographic programming language with Multiply Located Values. He-Lambda-Small allows multicasting to a set of parties, and the resulting value will be located at all of them. This approach enables a simple and elegant alternative to "select": He-Lambda-Small requires that the guard for a conditional be located at all of the relevant parties. In He-Lambda-Small, checking that a choreography is well-typed suffices to show that it is deadlock-free. We present several case studies that demonstrate the use of multiply-located values to concisely encode tricky communication patterns described in previous work without the use of "select" or redundant communication.<|reference_end|>
@article{bates2024we,
    title={We Know I Know You Know; Choreographic Programming With Multicast and
  Multiply Located Values},
    author={Mako Bates, Joseph P. Near},
    journal={arXiv preprint arXiv:2403.05417},
    year={2024},
    archivePrefix={arXiv},
    eprint={2403.05417},
    primaryClass={cs.PL cs.DC}
}