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Documents authored by Yoshida, Nobuko

Document
DOI: 10.4230/LIPIcs.ECOOP.2024.19
Fearless Asynchronous Communications with Timed Multiparty Session Protocols

Authors: Ping Hou, Nicolas Lagaillardie, and Nobuko Yoshida

Published in: LIPIcs, Volume 313, 38th European Conference on Object-Oriented Programming (ECOOP 2024)

Abstract
Session types using affinity and exception handling mechanisms have been developed to ensure the communication safety of protocols implemented in concurrent and distributed programming languages. Nevertheless, current affine session types are inadequate for specifying real-world asynchronous protocols, as they are usually imposed by time constraints which enable timeout exceptions to prevent indefinite blocking while awaiting valid messages. This paper proposes the first formal integration of affinity, time constraints, timeouts, and time-failure handling based on multiparty session types for supporting reliability in asynchronous distributed systems. With this theory, we statically guarantee that asynchronous timed communication is deadlock-free, communication safe, while being fearless - never hindered by timeout errors or abrupt terminations. To implement our theory, we introduce MultiCrusty^T, a Rust toolchain designed to facilitate the implementation of safe affine timed protocols. MultiCrusty^T leverages generic types and the time library to handle timed communications, integrated with optional types for affinity. We evaluate MultiCrusty^T by extending diverse examples from the literature to incorporate time and timeouts. We also showcase the correctness by construction of our approach by implementing various real-world use cases, including protocols from the Internet of Remote Things domain and real-time systems.
Cite as

Ping Hou, Nicolas Lagaillardie, and Nobuko Yoshida. Fearless Asynchronous Communications with Timed Multiparty Session Protocols. In 38th European Conference on Object-Oriented Programming (ECOOP 2024). Leibniz International Proceedings in Informatics (LIPIcs), Volume 313, pp. 19:1-19:30, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)

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@InProceedings{hou_et_al:LIPIcs.ECOOP.2024.19,
  author =	{Hou, Ping and Lagaillardie, Nicolas and Yoshida, Nobuko},
  title =	{{Fearless Asynchronous Communications with Timed Multiparty Session Protocols}},
  booktitle =	{38th European Conference on Object-Oriented Programming (ECOOP 2024)},
  pages =	{19:1--19:30},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-341-6},
  ISSN =	{1868-8969},
  year =	{2024},
  volume =	{313},
  editor =	{Aldrich, Jonathan and Salvaneschi, Guido},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2024.19},
  URN =		{urn:nbn:de:0030-drops-208681},
  doi =		{10.4230/LIPIcs.ECOOP.2024.19},
  annote =	{Keywords: Session Types, Concurrency, Time Failure Handling, Affinity, Timeout, Rust}
}
Document
DOI: 10.4230/LIPIcs.ECOOP.2024.41
Refinements for Multiparty Message-Passing Protocols: Specification-Agnostic Theory and Implementation

Authors: Martin Vassor and Nobuko Yoshida

Published in: LIPIcs, Volume 313, 38th European Conference on Object-Oriented Programming (ECOOP 2024)

Abstract
Multiparty message-passing protocols are notoriously difficult to design, due to interaction mismatches that lead to errors such as deadlocks. Existing protocol specification formats have been developed to prevent such errors (e.g. multiparty session types (MPST)). In order to further constrain protocols, specifications can be extended with refinements, i.e. logical predicates to control the behaviour of the protocol based on previous values exchanged. Unfortunately, existing refinement theories and implementations are tightly coupled with specification formats. This paper proposes a framework for multiparty message-passing protocols with refinements and its implementation in Rust. Our work decouples correctness of refinements from the underlying model of computation, which results in a specification-agnostic framework. Our contributions are threefold. First, we introduce a trace system which characterises valid refined traces, i.e. a sequence of sending and receiving actions correct with respect to refinements. Second, we give a correct model of computation named refined communicating system (RCS), which is an extension of communicating automata systems with refinements. We prove that RCS only produce valid refined traces. We show how to generate RCS from mainstream protocol specification formats, such as refined multiparty session types (RMPST) or refined choreography automata. Third, we illustrate the flexibility of the framework by developing both a static analysis technique and an improved model of computation for dynamic refinement evaluation. Finally, we provide a Rust toolchain for decentralised RMPST, evaluate our implementation with a set of benchmarks from the literature, and observe that refinement overhead is negligible.
Cite as

Martin Vassor and Nobuko Yoshida. Refinements for Multiparty Message-Passing Protocols: Specification-Agnostic Theory and Implementation. In 38th European Conference on Object-Oriented Programming (ECOOP 2024). Leibniz International Proceedings in Informatics (LIPIcs), Volume 313, pp. 41:1-41:29, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)

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@InProceedings{vassor_et_al:LIPIcs.ECOOP.2024.41,
  author =	{Vassor, Martin and Yoshida, Nobuko},
  title =	{{Refinements for Multiparty Message-Passing Protocols: Specification-Agnostic Theory and Implementation}},
  booktitle =	{38th European Conference on Object-Oriented Programming (ECOOP 2024)},
  pages =	{41:1--41:29},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-341-6},
  ISSN =	{1868-8969},
  year =	{2024},
  volume =	{313},
  editor =	{Aldrich, Jonathan and Salvaneschi, Guido},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2024.41},
  URN =		{urn:nbn:de:0030-drops-208906},
  doi =		{10.4230/LIPIcs.ECOOP.2024.41},
  annote =	{Keywords: Message-Passing Concurrency, Session Types, Specification}
}
Document
Artifact
DOI: 10.4230/DARTS.10.2.10
Fearless Asynchronous Communications with Timed Session Types in Rust (Artifact)

Authors: Nicolas Lagaillardie, Ping Hou, and Nobuko Yoshida

Published in: DARTS, Volume 10, Issue 2, Special Issue of the 38th European Conference on Object-Oriented Programming (ECOOP 2024)

Abstract
We introduce MultiCrusty^T, a Rust toolchain designed to facilitate the implementation of safe affine timed protocols. MultiCrusty^T leverages generic types and the time library to handle timed communications, integrated with optional types for affinity. This artifact allows to evaluate our approach by running examples from the literature, real-world use cases and protocols from real-time systems, featured in the related article, showcasing the correctness by construction of our approach. We allow to see the performance of our solution by running benchmarks and generating graphs, highlighting a less than 10% compile-time and runtime overhead compared with an untimed implementation. We also demonstrate how to implement, step by step, your own timed protocols, from a very basic one with only two parties and simple interactions, to complex ones with more than three parties, choices and recursion.
Cite as

Nicolas Lagaillardie, Ping Hou, and Nobuko Yoshida. Fearless Asynchronous Communications with Timed Session Types in Rust (Artifact). In Special Issue of the 38th European Conference on Object-Oriented Programming (ECOOP 2024). Dagstuhl Artifacts Series (DARTS), Volume 10, Issue 2, pp. 10:1-10:3, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)

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@Article{lagaillardie_et_al:DARTS.10.2.10,
  author =	{Lagaillardie, Nicolas and Hou, Ping and Yoshida, Nobuko},
  title =	{{Fearless Asynchronous Communications with Timed Session Types in Rust (Artifact)}},
  pages =	{10:1--10:3},
  journal =	{Dagstuhl Artifacts Series},
  ISBN =	{978-3-95977-342-3},
  ISSN =	{2509-8195},
  year =	{2024},
  volume =	{10},
  number =	{2},
  editor =	{Lagaillardie, Nicolas and Hou, Ping and Yoshida, Nobuko},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DARTS.10.2.10},
  URN =		{urn:nbn:de:0030-drops-209084},
  doi =		{10.4230/DARTS.10.2.10},
  annote =	{Keywords: session types, affine types, \pi-calculus, asynchrony, timeouts, failures, Rust}
}
Document
Artifact
DOI: 10.4230/DARTS.10.2.23
Refinements for Multiparty Message-Passing Protocols: Specification-Agnostic Theory and Implementation (Artifact)

Authors: Martin Vassor and Nobuko Yoshida

Published in: DARTS, Volume 10, Issue 2, Special Issue of the 38th European Conference on Object-Oriented Programming (ECOOP 2024)

Abstract
Multiparty message-passing protocols are notoriously difficult to design, due to interaction mismatches that lead to errors such as deadlocks. Existing protocol specification formats have been developed to prevent such errors (e.g. multiparty session types (MPST)). In order to further constrain protocols, specifications can be extended with refinements, i.e. logical predicates to control the behaviour of the protocol based on previous values exchanged. Unfortunately, existing refinement theories and implementations are tightly coupled with specification formats. This artifact accompanies [Martin Vassor and Nobuko Yoshida, 2024]. It presents an implementation of the framework presented in this paper.
Cite as

Martin Vassor and Nobuko Yoshida. Refinements for Multiparty Message-Passing Protocols: Specification-Agnostic Theory and Implementation (Artifact). In Special Issue of the 38th European Conference on Object-Oriented Programming (ECOOP 2024). Dagstuhl Artifacts Series (DARTS), Volume 10, Issue 2, pp. 23:1-23:5, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)

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@Article{vassor_et_al:DARTS.10.2.23,
  author =	{Vassor, Martin and Yoshida, Nobuko},
  title =	{{Refinements for Multiparty Message-Passing Protocols: Specification-Agnostic Theory and Implementation (Artifact)}},
  pages =	{23:1--23:5},
  journal =	{Dagstuhl Artifacts Series},
  ISBN =	{978-3-95977-342-3},
  ISSN =	{2509-8195},
  year =	{2024},
  volume =	{10},
  number =	{2},
  editor =	{Vassor, Martin and Yoshida, Nobuko},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DARTS.10.2.23},
  URN =		{urn:nbn:de:0030-drops-209212},
  doi =		{10.4230/DARTS.10.2.23},
  annote =	{Keywords: Message-Passing Concurrency, Session Types, Specification}
}
Document
DOI: 10.4230/LIPIcs.ITP.2024.13
Completeness of Asynchronous Session Tree Subtyping in Coq

Authors: Burak Ekici and Nobuko Yoshida

Published in: LIPIcs, Volume 309, 15th International Conference on Interactive Theorem Proving (ITP 2024)

Abstract
Multiparty session types (MPST) serve as a foundational framework for formally specifying and verifying message passing protocols. Asynchronous subtyping in MPST allows for typing optimised programs preserving type safety and deadlock freedom under asynchronous interactions where the message order is preserved and sending is non-blocking. The optimisation is obtained by message reordering, which allows for sending messages earlier or receiving them later. Sound subtyping algorithms have been extensively studied and implemented as part of various programming languages and tools including C, Rust and C-MPI. However, formalising all such permutations under sequencing, selection, branching and recursion in session types is an intricate task. Additionally, checking asynchronous subtyping has been proven to be undecidable. This paper introduces the first formalisation of asynchronous subtyping in MPST within the Coq proof assistant. We first decompose session types into session trees that do not involve branching and selection, and then establish a coinductive refinement relation over them to govern subtyping. To showcase our formalisation, we prove example subtyping schemas that appear in the literature, all of which cannot be verified, at the same time, by any of the existing decidable sound algorithms. Additionally, we take the (inductive) negation of the refinement relation from a prior work by Ghilezan et al. [Ghilezan et al., 2023] and re-implement it, significantly reducing the number of rules (from eighteen to eight). We establish the completeness of subtyping with respect to its negation in Coq, addressing the issues concerning the negation rules outlined in the previous work [Ghilezan et al., 2023]. In the formalisation, we use the greatest fixed point of the least fixed point technique, facilitated by the paco library, to define coinductive predicates. We employ parametrised coinduction to prove their properties. The formalisation consists of roughly 10K lines of Coq code, accessible at: https://github.com/ekiciburak/sessionTreeST/tree/itp2024.
Cite as

Burak Ekici and Nobuko Yoshida. Completeness of Asynchronous Session Tree Subtyping in Coq. In 15th International Conference on Interactive Theorem Proving (ITP 2024). Leibniz International Proceedings in Informatics (LIPIcs), Volume 309, pp. 13:1-13:20, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)

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@InProceedings{ekici_et_al:LIPIcs.ITP.2024.13,
  author =	{Ekici, Burak and Yoshida, Nobuko},
  title =	{{Completeness of Asynchronous Session Tree Subtyping in Coq}},
  booktitle =	{15th International Conference on Interactive Theorem Proving (ITP 2024)},
  pages =	{13:1--13:20},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-337-9},
  ISSN =	{1868-8969},
  year =	{2024},
  volume =	{309},
  editor =	{Bertot, Yves and Kutsia, Temur and Norrish, Michael},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ITP.2024.13},
  URN =		{urn:nbn:de:0030-drops-207418},
  doi =		{10.4230/LIPIcs.ITP.2024.13},
  annote =	{Keywords: asynchronous multiparty session types, session trees, subtyping, Coq}
}
Document
DOI: 10.4230/LIPIcs.ECOOP.2023.1
Designing Asynchronous Multiparty Protocols with Crash-Stop Failures

Authors: Adam D. Barwell, Ping Hou, Nobuko Yoshida, and Fangyi Zhou

Published in: LIPIcs, Volume 263, 37th European Conference on Object-Oriented Programming (ECOOP 2023)

Abstract
Session types provide a typing discipline for message-passing systems. However, most session type approaches assume an ideal world: one in which everything is reliable and without failures. Yet this is in stark contrast with distributed systems in the real world. To address this limitation, we introduce Teatrino, a code generation toolchain that utilises asynchronous multiparty session types (MPST) with crash-stop semantics to support failure handling protocols. We augment asynchronous MPST and processes with crash handling branches. Our approach requires no user-level syntax extensions for global types and features a formalisation of global semantics, which captures complex behaviours induced by crashed/crash handling processes. The sound and complete correspondence between global and local type semantics guarantees deadlock-freedom, protocol conformance, and liveness of typed processes in the presence of crashes. Our theory is implemented in the toolchain Teatrino, which provides correctness by construction. Teatrino extends the Scribble multiparty protocol language to generate protocol-conforming Scala code, using the Effpi concurrent programming library. We extend both Scribble and Effpi to support crash-stop behaviour. We demonstrate the feasibility of our methodology and evaluate Teatrino with examples extended from both session type and distributed systems literature.
Cite as

Adam D. Barwell, Ping Hou, Nobuko Yoshida, and Fangyi Zhou. Designing Asynchronous Multiparty Protocols with Crash-Stop Failures. In 37th European Conference on Object-Oriented Programming (ECOOP 2023). Leibniz International Proceedings in Informatics (LIPIcs), Volume 263, pp. 1:1-1:30, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)

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@InProceedings{barwell_et_al:LIPIcs.ECOOP.2023.1,
  author =	{Barwell, Adam D. and Hou, Ping and Yoshida, Nobuko and Zhou, Fangyi},
  title =	{{Designing Asynchronous Multiparty Protocols with Crash-Stop Failures}},
  booktitle =	{37th European Conference on Object-Oriented Programming (ECOOP 2023)},
  pages =	{1:1--1:30},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-281-5},
  ISSN =	{1868-8969},
  year =	{2023},
  volume =	{263},
  editor =	{Ali, Karim and Salvaneschi, Guido},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2023.1},
  URN =		{urn:nbn:de:0030-drops-181944},
  doi =		{10.4230/LIPIcs.ECOOP.2023.1},
  annote =	{Keywords: Session Types, Concurrency, Failure Handling, Code Generation, Scala}
}
Document
DOI: 10.4230/LIPIcs.ECOOP.2023.6
Dynamically Updatable Multiparty Session Protocols: Generating Concurrent Go Code from Unbounded Protocols

Authors: David Castro-Perez and Nobuko Yoshida

Published in: LIPIcs, Volume 263, 37th European Conference on Object-Oriented Programming (ECOOP 2023)

Abstract
Multiparty Session Types (MPST) are a typing disciplines that guarantee the absence of deadlocks and communication errors in concurrent and distributed systems. However, existing MPST frameworks do not support protocols with dynamic unbounded participants, and cannot express many common programming patterns that require the introduction of new participants into a protocol. This poses a barrier for the adoption of MPST in languages that favour the creation of new participants (processes, lightweight threads, etc) that communicate via message passing, such as Go or Erlang. This paper proposes Dynamically Updatable Multiparty Session Protocols, a new MPST theory (DMst) that supports protocols with an unbounded number of fresh participants, whose communication topologies are dynamically updatable. We prove that DMst guarantees deadlock-freedom and liveness. We implement a toolchain, GoScr (Go-Scribble), which generates Go implementations from DMst, ensuring by construction, that the different participants will only perform I/O actions that comply with a given protocol specification. We evaluate our toolchain by (1) implementing representative parallel and concurrent algorithms from existing benchmarks, textbooks and literature; (2) showing that GoScr does not introduce significant overheads compared to a naive implementation, for computationally expensive benchmarks; and (3) building three realistic protocols (dynamic task delegation, recursive Domain Name System, and a parallel Min-Max strategy) in GoScr that could not be represented with previous theories of session types.
Cite as

David Castro-Perez and Nobuko Yoshida. Dynamically Updatable Multiparty Session Protocols: Generating Concurrent Go Code from Unbounded Protocols. In 37th European Conference on Object-Oriented Programming (ECOOP 2023). Leibniz International Proceedings in Informatics (LIPIcs), Volume 263, pp. 6:1-6:30, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)

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@InProceedings{castroperez_et_al:LIPIcs.ECOOP.2023.6,
  author =	{Castro-Perez, David and Yoshida, Nobuko},
  title =	{{Dynamically Updatable Multiparty Session Protocols: Generating Concurrent Go Code from Unbounded Protocols}},
  booktitle =	{37th European Conference on Object-Oriented Programming (ECOOP 2023)},
  pages =	{6:1--6:30},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-281-5},
  ISSN =	{1868-8969},
  year =	{2023},
  volume =	{263},
  editor =	{Ali, Karim and Salvaneschi, Guido},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2023.6},
  URN =		{urn:nbn:de:0030-drops-181995},
  doi =		{10.4230/LIPIcs.ECOOP.2023.6},
  annote =	{Keywords: Multiparty Session Types, Correctness-by-construction, Concurrency, Golang}
}
Document
Artifact
DOI: 10.4230/DARTS.9.2.9
Designing Asynchronous Multiparty Protocols with Crash-Stop Failures (Artifact)

Authors: Adam D. Barwell, Ping Hou, Nobuko Yoshida, and Fangyi Zhou

Published in: DARTS, Volume 9, Issue 2, Special Issue of the 37th European Conference on Object-Oriented Programming (ECOOP 2023)

Abstract
We introduce Teatrino, a toolchain that supports handling multiparty protocols with crash-stop failures and crash-handling behaviours. Teatrino accompanies the novel MPST theory in the related article, and enables users to generate fault-tolerant protocol-conforming Scala code from Scribble protocols. Local types are projected from the global protocol, enabling correctness-by-construction, and are expressed directly as Scala types via the Effpi concurrency library. Teatrino extends both Scribble and Effpi with support for crash-stop behaviour. The generated Scala code is executable and can be further integrated with existing systems. The accompanying theory in the related article guarantees deadlock-freedom and liveness properties for failure handling protocols and their implementation. This artifact includes examples, extended from both session type and distributed systems literature, featured in the related article.
Cite as

Adam D. Barwell, Ping Hou, Nobuko Yoshida, and Fangyi Zhou. Designing Asynchronous Multiparty Protocols with Crash-Stop Failures (Artifact). In Special Issue of the 37th European Conference on Object-Oriented Programming (ECOOP 2023). Dagstuhl Artifacts Series (DARTS), Volume 9, Issue 2, pp. 9:1-9:3, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)

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@Article{barwell_et_al:DARTS.9.2.9,
  author =	{Barwell, Adam D. and Hou, Ping and Yoshida, Nobuko and Zhou, Fangyi},
  title =	{{Designing Asynchronous Multiparty Protocols with Crash-Stop Failures (Artifact)}},
  pages =	{9:1--9:3},
  journal =	{Dagstuhl Artifacts Series},
  ISSN =	{2509-8195},
  year =	{2023},
  volume =	{9},
  number =	{2},
  editor =	{Barwell, Adam D. and Hou, Ping and Yoshida, Nobuko and Zhou, Fangyi},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DARTS.9.2.9},
  URN =		{urn:nbn:de:0030-drops-182492},
  doi =		{10.4230/DARTS.9.2.9},
  annote =	{Keywords: Session Types, Concurrency, Failure Handling, Code Generation, Scala}
}
Document
Artifact
DOI: 10.4230/DARTS.9.2.10
Dynamically Updatable Multiparty Session Protocols (Artifact)

Authors: David Castro-Perez and Nobuko Yoshida

Published in: DARTS, Volume 9, Issue 2, Special Issue of the 37th European Conference on Object-Oriented Programming (ECOOP 2023)

Abstract
Multiparty Session Types (MPST) are typing disciplines that guarantee the absence of deadlocks and communication errors in concurrent and distributed systems. However, existing MPST frameworks do not support protocols with dynamic unbounded participants, and cannot express many common programming patterns that require the introduction of new participants into a protocol. This poses a barrier for the adoption of MPST in languages that favour the creation of new participants (processes, lightweight threads, etc) that communicate via message passing, such as Go or Erlang. This artifact contains an implementation of Dynamically Updatable Multiparty Session Protocols, a new MPST theory (DMst) that supports protocols with an unbounded number of fresh participants, whose communication topologies are dynamically updatable. DMst guarantees deadlock-freedom and liveness. The artifact comprises a toolchain, GoScr (Go-Scribble), which generates Go implementations from DMst, ensuring by construction, that the different participants will only perform I/O actions that comply with a given protocol specification. We evaluate GoScr by (1) implementing representative parallel and concurrent algorithms from existing benchmarks, textbooks and literature; (2) showing that GoScr does not introduce significant overheads compared to a naive implementation, for computationally expensive benchmarks; and (3) building three realistic protocols (dynamic task delegation, recursive Domain Name System, and a parallel Min-Max strategy) in GoScr that could not be represented with previous theories of session types.
Cite as

David Castro-Perez and Nobuko Yoshida. Dynamically Updatable Multiparty Session Protocols (Artifact). In Special Issue of the 37th European Conference on Object-Oriented Programming (ECOOP 2023). Dagstuhl Artifacts Series (DARTS), Volume 9, Issue 2, pp. 10:1-10:2, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)

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@Article{castroperez_et_al:DARTS.9.2.10,
  author =	{Castro-Perez, David and Yoshida, Nobuko},
  title =	{{Dynamically Updatable Multiparty Session Protocols (Artifact)}},
  pages =	{10:1--10:2},
  journal =	{Dagstuhl Artifacts Series},
  ISSN =	{2509-8195},
  year =	{2023},
  volume =	{9},
  number =	{2},
  editor =	{Castro-Perez, David and Yoshida, Nobuko},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DARTS.9.2.10},
  URN =		{urn:nbn:de:0030-drops-182505},
  doi =		{10.4230/DARTS.9.2.10},
  annote =	{Keywords: Multiparty Session Types, Correctness-by-construction, Concurrency, Golang}
}
Document
DOI: 10.4230/LIPIcs.CONCUR.2022.35
Generalised Multiparty Session Types with Crash-Stop Failures

Authors: Adam D. Barwell, Alceste Scalas, Nobuko Yoshida, and Fangyi Zhou

Published in: LIPIcs, Volume 243, 33rd International Conference on Concurrency Theory (CONCUR 2022)

Abstract
Session types enable the specification and verification of communicating systems. However, their theory often assumes that processes never fail. To address this limitation, we present a generalised multiparty session type (MPST) theory with crash-stop failures, where processes can crash arbitrarily. Our new theory validates more protocols and processes w.r.t. previous work. We apply minimal syntactic changes to standard session π-calculus and types: we model crashes and their handling semantically, with a generalised MPST typing system parametric on a behavioural safety property. We cover the spectrum between fully reliable and fully unreliable sessions, via optional reliability assumptions, and prove type safety and protocol conformance in the presence of crash-stop failures. Introducing crash-stop failures has non-trivial consequences: writing correct processes that handle all crash scenarios can be difficult. Yet, our generalised MPST theory allows us to tame this complexity, via model checking, to validate whether a multiparty session satisfies desired behavioural properties, e.g. deadlock-freedom or liveness, even in presence of crashes. We implement our approach using the mCRL2 model checker, and evaluate it with examples extended from the literature.
Cite as

Adam D. Barwell, Alceste Scalas, Nobuko Yoshida, and Fangyi Zhou. Generalised Multiparty Session Types with Crash-Stop Failures. In 33rd International Conference on Concurrency Theory (CONCUR 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 243, pp. 35:1-35:25, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)

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@InProceedings{barwell_et_al:LIPIcs.CONCUR.2022.35,
  author =	{Barwell, Adam D. and Scalas, Alceste and Yoshida, Nobuko and Zhou, Fangyi},
  title =	{{Generalised Multiparty Session Types with Crash-Stop Failures}},
  booktitle =	{33rd International Conference on Concurrency Theory (CONCUR 2022)},
  pages =	{35:1--35:25},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-246-4},
  ISSN =	{1868-8969},
  year =	{2022},
  volume =	{243},
  editor =	{Klin, Bartek and Lasota, S{\l}awomir and Muscholl, Anca},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CONCUR.2022.35},
  URN =		{urn:nbn:de:0030-drops-170982},
  doi =		{10.4230/LIPIcs.CONCUR.2022.35},
  annote =	{Keywords: Session Types, Concurrency, Failure Handling, Model Checking}
}
Document
Artifact
DOI: 10.4230/DARTS.8.2.9
Stay Safe Under Panic: Affine Rust Programming with Multiparty Session Types (Artifact)

Authors: Nicolas Lagaillardie, Rumyana Neykova, and Nobuko Yoshida

Published in: DARTS, Volume 8, Issue 2, Special Issue of the 36th European Conference on Object-Oriented Programming (ECOOP 2022)

Abstract
This artifact contains a version of MultiCrusty, a Rust library designed for writing and checking communication protocols following the Affine Multiparty Session Types theory introduced in our ECOOP'22 paper. MultiCrusty can work, and should be used, with Scribble [Yoshida et al., 2014] and kMC [{Julien} {Lange} and {Nobuko} {Yoshida}, 2019]: with the former tool, users can write correct global protocols and project them onto local Rust types defined within MultiCrusty, this approach is qualified as top-down; while the latter tool allows to check local Rust types written by users, this approach is qualified as bottom-up. Our artifact contains those three tools, their respective source files, as well as the different examples and benchmarks introduced in our paper, all together within a Docker image.
Cite as

Nicolas Lagaillardie, Rumyana Neykova, and Nobuko Yoshida. Stay Safe Under Panic: Affine Rust Programming with Multiparty Session Types (Artifact). In Special Issue of the 36th European Conference on Object-Oriented Programming (ECOOP 2022). Dagstuhl Artifacts Series (DARTS), Volume 8, Issue 2, pp. 9:1-9:16, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)

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@Article{lagaillardie_et_al:DARTS.8.2.9,
  author =	{Lagaillardie, Nicolas and Neykova, Rumyana and Yoshida, Nobuko},
  title =	{{Stay Safe Under Panic: Affine Rust Programming with Multiparty Session Types (Artifact)}},
  pages =	{9:1--9:16},
  journal =	{Dagstuhl Artifacts Series},
  ISSN =	{2509-8195},
  year =	{2022},
  volume =	{8},
  number =	{2},
  editor =	{Lagaillardie, Nicolas and Neykova, Rumyana and Yoshida, Nobuko},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DARTS.8.2.9},
  URN =		{urn:nbn:de:0030-drops-162075},
  doi =		{10.4230/DARTS.8.2.9},
  annote =	{Keywords: Rust language, affine multiparty session types, failures, cancellation}
}
Document
Artifact
DOI: 10.4230/DARTS.8.2.21
Design-by-Contract for Flexible Multiparty Session Protocols (Artifact)

Authors: Lorenzo Gheri, Ivan Lanese, Neil Sayers, Emilio Tuosto, and Nobuko Yoshida

Published in: DARTS, Volume 8, Issue 2, Special Issue of the 36th European Conference on Object-Oriented Programming (ECOOP 2022)

Abstract
We introduce CAScr, the first implementation of Scribble (http://www.scribble.org, https://nuscr.dev/) that relies on choreography automata, for deadlock-free distributed programming. CAScr supports the main theoretical results and constructions in the related article. CAScr takes the popular top-down approach to system development, based on choreographic models, following the original methodology of Scribble and multiparty session types. The top-down approach enables correctness-by-construction: a developer provides a global description for the whole communication protocol; by projecting the global protocol, APIs are generated from local CFSMs, which ensure the safe implementation of each participant. The theory of choreography automata in the related article guarantees deadlock freedom for the distributed implementation of flexible global protocols. We target web development, supporting in particular the TypeScript programming language.
Cite as

Lorenzo Gheri, Ivan Lanese, Neil Sayers, Emilio Tuosto, and Nobuko Yoshida. Design-by-Contract for Flexible Multiparty Session Protocols (Artifact). In Special Issue of the 36th European Conference on Object-Oriented Programming (ECOOP 2022). Dagstuhl Artifacts Series (DARTS), Volume 8, Issue 2, pp. 21:1-21:5, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)

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@Article{gheri_et_al:DARTS.8.2.21,
  author =	{Gheri, Lorenzo and Lanese, Ivan and Sayers, Neil and Tuosto, Emilio and Yoshida, Nobuko},
  title =	{{Design-by-Contract for Flexible Multiparty Session Protocols (Artifact)}},
  pages =	{21:1--21:5},
  journal =	{Dagstuhl Artifacts Series},
  ISSN =	{2509-8195},
  year =	{2022},
  volume =	{8},
  number =	{2},
  editor =	{Gheri, Lorenzo and Lanese, Ivan and Sayers, Neil and Tuosto, Emilio and Yoshida, Nobuko},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DARTS.8.2.21},
  URN =		{urn:nbn:de:0030-drops-162196},
  doi =		{10.4230/DARTS.8.2.21},
  annote =	{Keywords: Choreography automata, design by contract, deadlock freedom, Communicating Finite State Machines, TypeScript programming}
}
Document
DOI: 10.4230/LIPIcs.ECOOP.2022.4
Stay Safe Under Panic: Affine Rust Programming with Multiparty Session Types

Authors: Nicolas Lagaillardie, Rumyana Neykova, and Nobuko Yoshida

Published in: LIPIcs, Volume 222, 36th European Conference on Object-Oriented Programming (ECOOP 2022)

Abstract
Communicating systems comprise diverse software components across networks. To ensure their robustness, modern programming languages such as Rust provide both strongly typed channels, whose usage is guaranteed to be affine (at most once), and cancellation operations over binary channels. For coordinating components to correctly communicate and synchronise with each other, we use the structuring mechanism from multiparty session types, extending it with affine communication channels and implicit/explicit cancellation mechanisms. This new typing discipline, affine multiparty session types (AMPST), ensures cancellation termination of multiple, independently running components and guarantees that communication will not get stuck due to error or abrupt termination. Guided by AMPST, we implemented an automated generation tool (MultiCrusty) of Rust APIs associated with cancellation termination algorithms, by which the Rust compiler auto-detects unsafe programs. Our evaluation shows that MultiCrusty provides an efficient mechanism for communication, synchronisation and propagation of the notifications of cancellation for arbitrary processes. We have implemented several usecases, including popular application protocols (OAuth, SMTP), and protocols with exception handling patterns (circuit breaker, distributed logging).
Cite as

Nicolas Lagaillardie, Rumyana Neykova, and Nobuko Yoshida. Stay Safe Under Panic: Affine Rust Programming with Multiparty Session Types. In 36th European Conference on Object-Oriented Programming (ECOOP 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 222, pp. 4:1-4:29, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)

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@InProceedings{lagaillardie_et_al:LIPIcs.ECOOP.2022.4,
  author =	{Lagaillardie, Nicolas and Neykova, Rumyana and Yoshida, Nobuko},
  title =	{{Stay Safe Under Panic: Affine Rust Programming with Multiparty Session Types}},
  booktitle =	{36th European Conference on Object-Oriented Programming (ECOOP 2022)},
  pages =	{4:1--4:29},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-225-9},
  ISSN =	{1868-8969},
  year =	{2022},
  volume =	{222},
  editor =	{Ali, Karim and Vitek, Jan},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2022.4},
  URN =		{urn:nbn:de:0030-drops-162324},
  doi =		{10.4230/LIPIcs.ECOOP.2022.4},
  annote =	{Keywords: Rust language, affine multiparty session types, failures, cancellation}
}
Document
DOI: 10.4230/LIPIcs.ECOOP.2022.8
Design-By-Contract for Flexible Multiparty Session Protocols

Authors: Lorenzo Gheri, Ivan Lanese, Neil Sayers, Emilio Tuosto, and Nobuko Yoshida

Published in: LIPIcs, Volume 222, 36th European Conference on Object-Oriented Programming (ECOOP 2022)

Abstract
Choreographic models support a correctness-by-construction principle in distributed programming. Also, they enable the automatic generation of correct message-based communication patterns from a global specification of the desired system behaviour. In this paper we extend the theory of choreography automata, a choreographic model based on finite-state automata, with two key features. First, we allow participants to act only in some of the scenarios described by the choreography automaton. While this seems natural, many choreographic approaches in the literature, and choreography automata in particular, forbid this behaviour. Second, we equip communications with assertions constraining the values that can be communicated, enabling a design-by-contract approach. We provide a toolchain allowing to exploit the theory above to generate APIs for TypeScript web programming. Programs communicating via the generated APIs follow, by construction, the prescribed communication pattern and are free from communication errors such as deadlocks.
Cite as

Lorenzo Gheri, Ivan Lanese, Neil Sayers, Emilio Tuosto, and Nobuko Yoshida. Design-By-Contract for Flexible Multiparty Session Protocols. In 36th European Conference on Object-Oriented Programming (ECOOP 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 222, pp. 8:1-8:28, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)

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@InProceedings{gheri_et_al:LIPIcs.ECOOP.2022.8,
  author =	{Gheri, Lorenzo and Lanese, Ivan and Sayers, Neil and Tuosto, Emilio and Yoshida, Nobuko},
  title =	{{Design-By-Contract for Flexible Multiparty Session Protocols}},
  booktitle =	{36th European Conference on Object-Oriented Programming (ECOOP 2022)},
  pages =	{8:1--8:28},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-225-9},
  ISSN =	{1868-8969},
  year =	{2022},
  volume =	{222},
  editor =	{Ali, Karim and Vitek, Jan},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2022.8},
  URN =		{urn:nbn:de:0030-drops-162367},
  doi =		{10.4230/LIPIcs.ECOOP.2022.8},
  annote =	{Keywords: Choreography automata, design by contract, deadlock freedom, Communicating Finite State Machines, TypeScript programming}
}
Document
Invited Paper
DOI: 10.4230/LIPIcs.CONCUR.2021.1
CONCUR Test-Of-Time Award 2021 (Invited Paper)

Authors: Nathalie Bertrand, Luca de Alfaro, Rob van Glabbeek, Catuscia Palamidessi, and Nobuko Yoshida

Published in: LIPIcs, Volume 203, 32nd International Conference on Concurrency Theory (CONCUR 2021)

Abstract
This short article announces the recipients of the CONCUR Test-of-Time Award 2021.
Cite as

Nathalie Bertrand, Luca de Alfaro, Rob van Glabbeek, Catuscia Palamidessi, and Nobuko Yoshida. CONCUR Test-Of-Time Award 2021 (Invited Paper). In 32nd International Conference on Concurrency Theory (CONCUR 2021). Leibniz International Proceedings in Informatics (LIPIcs), Volume 203, pp. 1:1-1:3, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2021)

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@InProceedings{bertrand_et_al:LIPIcs.CONCUR.2021.1,
  author =	{Bertrand, Nathalie and de Alfaro, Luca and van Glabbeek, Rob and Palamidessi, Catuscia and Yoshida, Nobuko},
  title =	{{CONCUR Test-Of-Time Award 2021}},
  booktitle =	{32nd International Conference on Concurrency Theory (CONCUR 2021)},
  pages =	{1:1--1:3},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-203-7},
  ISSN =	{1868-8969},
  year =	{2021},
  volume =	{203},
  editor =	{Haddad, Serge and Varacca, Daniele},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CONCUR.2021.1},
  URN =		{urn:nbn:de:0030-drops-143786},
  doi =		{10.4230/LIPIcs.CONCUR.2021.1},
  annote =	{Keywords: Concurrency, CONCUR Test-of-Time Award}
}
Document
Artifact
DOI: 10.4230/DARTS.6.2.12
Static Race Detection and Mutex Safety and Liveness for Go Programs (Artifact)

Authors: Julia Gabet and Nobuko Yoshida

Published in: DARTS, Volume 6, Issue 2, Special Issue of the 34th European Conference on Object-Oriented Programming (ECOOP 2020)

Abstract
This artifact contains a version of the Godel tool that checks MiGo+ types - an extension of MiGo from [Lange et al., 2018] including GoL. Given the extracted MiGo+ types, the tool can analyse them using the mCRL2 model checker to check several properties including liveness, safety and data race freedom as defined in our paper. The artifact also includes examples, shipped with both the source of the Godel tool and the benchmark repository. The latter also contains the Go source for the benchmark examples. We provide compiled binaries of the artifact in a Docker image, with instructions on how to use them. Finally, for convenience, the Docker image also contains a binary version of the migoinfer+ tool, developed as a fork from the original migoinfer by Nicholas Ng in [Lange et al., 2018]. This new version adds the ability to extract shared memory pointers as well as Mutex and RWMutex locks.
Cite as

Julia Gabet and Nobuko Yoshida. Static Race Detection and Mutex Safety and Liveness for Go Programs (Artifact). In Special Issue of the 34th European Conference on Object-Oriented Programming (ECOOP 2020). Dagstuhl Artifacts Series (DARTS), Volume 6, Issue 2, pp. 12:1-12:3, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)

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@Article{gabet_et_al:DARTS.6.2.12,
  author =	{Gabet, Julia and Yoshida, Nobuko},
  title =	{{Static Race Detection and Mutex Safety and Liveness for Go Programs (Artifact)}},
  pages =	{12:1--12:3},
  journal =	{Dagstuhl Artifacts Series},
  ISSN =	{2509-8195},
  year =	{2020},
  volume =	{6},
  number =	{2},
  editor =	{Gabet, Julia and Yoshida, Nobuko},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DARTS.6.2.12},
  URN =		{urn:nbn:de:0030-drops-132096},
  doi =		{10.4230/DARTS.6.2.12},
  annote =	{Keywords: Go language, behavioural types, race detection, happens-before relation, safety, liveness}
}
Document
Artifact
DOI: 10.4230/DARTS.6.2.18
Multiparty Session Programming with Global Protocol Combinators (Artifact)

Authors: Keigo Imai, Rumyana Neykova, Nobuko Yoshida, and Shoji Yuen

Published in: DARTS, Volume 6, Issue 2, Special Issue of the 34th European Conference on Object-Oriented Programming (ECOOP 2020)

Abstract
In the paper "Multiparty Session Programming with Global Protocol Combinators", we introduce a library, ocaml-mpst for programming with global combinators - a set of functions for writing and verifying multiparty protocols in OCaml. Local behaviours for all processes in a protocol are inferred at once from a global combinator. Our approach enables fully-static verification and implementation of the whole protocol, from the protocol specification to the process implementations, to happen in the same language. This artifact is the source code of ocaml-mpst, with all the examples and benchmarks discussed in the paper.
Cite as

Keigo Imai, Rumyana Neykova, Nobuko Yoshida, and Shoji Yuen. Multiparty Session Programming with Global Protocol Combinators (Artifact). In Special Issue of the 34th European Conference on Object-Oriented Programming (ECOOP 2020). Dagstuhl Artifacts Series (DARTS), Volume 6, Issue 2, pp. 18:1-18:2, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)

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@Article{imai_et_al:DARTS.6.2.18,
  author =	{Imai, Keigo and Neykova, Rumyana and Yoshida, Nobuko and Yuen, Shoji},
  title =	{{Multiparty Session Programming with Global Protocol Combinators (Artifact)}},
  pages =	{18:1--18:2},
  journal =	{Dagstuhl Artifacts Series},
  ISSN =	{2509-8195},
  year =	{2020},
  volume =	{6},
  number =	{2},
  editor =	{Imai, Keigo and Neykova, Rumyana and Yoshida, Nobuko and Yuen, Shoji},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DARTS.6.2.18},
  URN =		{urn:nbn:de:0030-drops-132159},
  doi =		{10.4230/DARTS.6.2.18},
  annote =	{Keywords: Multiparty Session Types, Communication Protocol, Concurrent and Distributed Programming, OCaml}
}
Document
DOI: 10.4230/LIPIcs.ECOOP.2020.4
Static Race Detection and Mutex Safety and Liveness for Go Programs

Authors: Julia Gabet and Nobuko Yoshida

Published in: LIPIcs, Volume 166, 34th European Conference on Object-Oriented Programming (ECOOP 2020)

Abstract
Go is a popular concurrent programming language thanks to its ability to efficiently combine concurrency and systems programming. In Go programs, a number of concurrency bugs can be caused by a mixture of data races and communication problems. In this paper, we develop a theory based on behavioural types to statically detect data races and deadlocks in Go programs. We first specify lock safety/liveness and data race properties over a Go program model, using the happens-before relation defined in the Go memory model. We represent these properties of programs in a μ-calculus model of types, and validate them using type-level model-checking. We then extend the framework to account for Go’s channels, and implement a static verification tool which can detect concurrency errors. This is, to the best of our knowledge, the first static verification framework of this kind for the Go language, uniformly analysing concurrency errors caused by a mix of shared memory accesses and asynchronous message-passing communications.
Cite as

Julia Gabet and Nobuko Yoshida. Static Race Detection and Mutex Safety and Liveness for Go Programs. In 34th European Conference on Object-Oriented Programming (ECOOP 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 166, pp. 4:1-4:30, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)

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@InProceedings{gabet_et_al:LIPIcs.ECOOP.2020.4,
  author =	{Gabet, Julia and Yoshida, Nobuko},
  title =	{{Static Race Detection and Mutex Safety and Liveness for Go Programs}},
  booktitle =	{34th European Conference on Object-Oriented Programming (ECOOP 2020)},
  pages =	{4:1--4:30},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-154-2},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{166},
  editor =	{Hirschfeld, Robert and Pape, Tobias},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2020.4},
  URN =		{urn:nbn:de:0030-drops-131615},
  doi =		{10.4230/LIPIcs.ECOOP.2020.4},
  annote =	{Keywords: Go language, behavioural types, race detection, happens-before relation, safety, liveness}
}
Document
DOI: 10.4230/LIPIcs.ECOOP.2020.9
Multiparty Session Programming With Global Protocol Combinators

Authors: Keigo Imai, Rumyana Neykova, Nobuko Yoshida, and Shoji Yuen

Published in: LIPIcs, Volume 166, 34th European Conference on Object-Oriented Programming (ECOOP 2020)

Abstract
Multiparty Session Types (MPST) is a typing discipline for communication protocols. It ensures the absence of communication errors and deadlocks for well-typed communicating processes. The state-of-the-art implementations of the MPST theory rely on (1) runtime linearity checks to ensure correct usage of communication channels and (2) external domain-specific languages for specifying and verifying multiparty protocols. To overcome these limitations, we propose a library for programming with global combinators - a set of functions for writing and verifying multiparty protocols in OCaml. Local behaviours for all processes in a protocol are inferred at once from a global combinator. We formalise global combinators and prove a sound realisability of global combinators - a well-typed global combinator derives a set of local types, by which typed endpoint programs can ensure type and communication safety. Our approach enables fully-static verification and implementation of the whole protocol, from the protocol specification to the process implementations, to happen in the same language. We compare our implementation to untyped and continuation-passing style implementations, and demonstrate its expressiveness by implementing a plethora of protocols. We show our library can interoperate with existing libraries and services, implementing DNS (Domain Name Service) protocol and the OAuth (Open Authentication) protocol.
Cite as

Keigo Imai, Rumyana Neykova, Nobuko Yoshida, and Shoji Yuen. Multiparty Session Programming With Global Protocol Combinators. In 34th European Conference on Object-Oriented Programming (ECOOP 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 166, pp. 9:1-9:30, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)

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@InProceedings{imai_et_al:LIPIcs.ECOOP.2020.9,
  author =	{Imai, Keigo and Neykova, Rumyana and Yoshida, Nobuko and Yuen, Shoji},
  title =	{{Multiparty Session Programming With Global Protocol Combinators}},
  booktitle =	{34th European Conference on Object-Oriented Programming (ECOOP 2020)},
  pages =	{9:1--9:30},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-154-2},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{166},
  editor =	{Hirschfeld, Robert and Pape, Tobias},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2020.9},
  URN =		{urn:nbn:de:0030-drops-131662},
  doi =		{10.4230/LIPIcs.ECOOP.2020.9},
  annote =	{Keywords: Multiparty Session Types, Communication Protocol, Concurrent and Distributed Programming, OCaml}
}
Document
DOI: 10.4230/LIPIcs.CONCUR.2019.38
A Sound Algorithm for Asynchronous Session Subtyping

Authors: Mario Bravetti, Marco Carbone, Julien Lange, Nobuko Yoshida, and Gianluigi Zavattaro

Published in: LIPIcs, Volume 140, 30th International Conference on Concurrency Theory (CONCUR 2019)

Abstract
Session types, types for structuring communication between endpoints in distributed systems, are recently being integrated into mainstream programming languages. In practice, a very important notion for dealing with such types is that of subtyping, since it allows for typing larger classes of system, where a program has not precisely the expected behavior but a similar one. Unfortunately, recent work has shown that subtyping for session types in an asynchronous setting is undecidable. To cope with this negative result, the only approaches we are aware of either restrict the syntax of session types or limit communication (by considering forms of bounded asynchrony). Both approaches are too restrictive in practice, hence we proceed differently by presenting an algorithm for checking subtyping which is sound, but not complete (in some cases it terminates without returning a decisive verdict). The algorithm is based on a tree representation of the coinductive definition of asynchronous subtyping; this tree could be infinite, and the algorithm checks for the presence of finite witnesses of infinite successful subtrees. Furthermore, we provide a tool that implements our algorithm and we apply it to many examples that cannot be managed with the previous approaches.
Cite as

Mario Bravetti, Marco Carbone, Julien Lange, Nobuko Yoshida, and Gianluigi Zavattaro. A Sound Algorithm for Asynchronous Session Subtyping. In 30th International Conference on Concurrency Theory (CONCUR 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 140, pp. 38:1-38:16, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)

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@InProceedings{bravetti_et_al:LIPIcs.CONCUR.2019.38,
  author =	{Bravetti, Mario and Carbone, Marco and Lange, Julien and Yoshida, Nobuko and Zavattaro, Gianluigi},
  title =	{{A Sound Algorithm for Asynchronous Session Subtyping}},
  booktitle =	{30th International Conference on Concurrency Theory (CONCUR 2019)},
  pages =	{38:1--38:16},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-121-4},
  ISSN =	{1868-8969},
  year =	{2019},
  volume =	{140},
  editor =	{Fokkink, Wan and van Glabbeek, Rob},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CONCUR.2019.38},
  URN =		{urn:nbn:de:0030-drops-109408},
  doi =		{10.4230/LIPIcs.CONCUR.2019.38},
  annote =	{Keywords: Session types, Concurrency, Subtyping, Algorithm}
}
Document
Brave New Idea Paper
DOI: 10.4230/LIPIcs.ECOOP.2019.28
Motion Session Types for Robotic Interactions (Brave New Idea Paper)

Authors: Rupak Majumdar, Marcus Pirron, Nobuko Yoshida, and Damien Zufferey

Published in: LIPIcs, Volume 134, 33rd European Conference on Object-Oriented Programming (ECOOP 2019)

Abstract
Robotics applications involve programming concurrent components synchronising through messages while simultaneously executing motion primitives that control the state of the physical world. Today, these applications are typically programmed in low-level imperative programming languages which provide little support for abstraction or reasoning. We present a unifying programming model for concurrent message-passing systems that additionally control the evolution of physical state variables, together with a compositional reasoning framework based on multiparty session types. Our programming model combines message-passing concurrent processes with motion primitives. Processes represent autonomous components in a robotic assembly, such as a cart or a robotic arm, and they synchronise via discrete messages as well as via motion primitives. Continuous evolution of trajectories under the action of controllers is also modelled by motion primitives, which operate in global, physical time. We use multiparty session types as specifications to orchestrate discrete message-passing concurrency and continuous flow of trajectories. A global session type specifies the communication protocol among the components with joint motion primitives. A projection from a global type ensures that jointly executed actions at end-points are communication safe and deadlock-free, i.e., session-typed components do not get stuck. Together, these checks provide a compositional verification methodology for assemblies of robotic components with respect to concurrency invariants such as a progress property of communications as well as dynamic invariants such as absence of collision. We have implemented our core language and, through initial experiments, have shown how multiparty session types can be used to specify and compositionally verify robotic systems implemented on top of off-the-shelf and custom hardware using standard robotics application libraries.
Cite as

Rupak Majumdar, Marcus Pirron, Nobuko Yoshida, and Damien Zufferey. Motion Session Types for Robotic Interactions (Brave New Idea Paper). In 33rd European Conference on Object-Oriented Programming (ECOOP 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 134, pp. 28:1-28:27, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)

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@InProceedings{majumdar_et_al:LIPIcs.ECOOP.2019.28,
  author =	{Majumdar, Rupak and Pirron, Marcus and Yoshida, Nobuko and Zufferey, Damien},
  title =	{{Motion Session Types for Robotic Interactions}},
  booktitle =	{33rd European Conference on Object-Oriented Programming (ECOOP 2019)},
  pages =	{28:1--28:27},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-111-5},
  ISSN =	{1868-8969},
  year =	{2019},
  volume =	{134},
  editor =	{Donaldson, Alastair F.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2019.28},
  URN =		{urn:nbn:de:0030-drops-108205},
  doi =		{10.4230/LIPIcs.ECOOP.2019.28},
  annote =	{Keywords: Session Types, Robotics, Concurrent Programming, Motions, Communications, Multiparty Session Types, Deadlock Freedom}
}
Document
DOI: 10.4230/DARTS.3.2.3
A Linear Decomposition of Multiparty Sessions for Safe Distributed Programming (Artifact)

Authors: Alceste Scalas, Ornela Dardha, Raymond Hu, and Nobuko Yoshida

Published in: DARTS, Volume 3, Issue 2, Special Issue of the 31st European Conference on Object-Oriented Programming (ECOOP 2017)

Abstract
This artifact contains a version of the Scribble tool that, given a protocol specification with multiple participants, can generate Scala APIs for implementing each participant in a type-safe, protocol-abiding way. Crucially, the API generation leverages a decomposition of the multiparty protocol into type-safe peer-to-peer interactions between pairs of participants; and this, in turn, allows to implement the API internals on top of the existing lchannels library for type-safe binary session programming. As a result, several technically challenging aspects in the implementation of multiparty sessions are solved "for free", at the underlying binary level. This includes distributed multiparty session delegation: this artifact implements it for the first time.
Cite as

Alceste Scalas, Ornela Dardha, Raymond Hu, and Nobuko Yoshida. A Linear Decomposition of Multiparty Sessions for Safe Distributed Programming (Artifact). In Special Issue of the 31st European Conference on Object-Oriented Programming (ECOOP 2017). Dagstuhl Artifacts Series (DARTS), Volume 3, Issue 2, pp. 3:1-3:3, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2017)

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@Article{scalas_et_al:DARTS.3.2.3,
  author =	{Scalas, Alceste and Dardha, Ornela and Hu, Raymond and Yoshida, Nobuko},
  title =	{{A Linear Decomposition of Multiparty Sessions for Safe Distributed Programming (Artifact)}},
  pages =	{3:1--3:3},
  journal =	{Dagstuhl Artifacts Series},
  ISSN =	{2509-8195},
  year =	{2017},
  volume =	{3},
  number =	{2},
  editor =	{Scalas, Alceste and Dardha, Ornela and Hu, Raymond and Yoshida, Nobuko},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DARTS.3.2.3},
  URN =		{urn:nbn:de:0030-drops-72847},
  doi =		{10.4230/DARTS.3.2.3},
  annote =	{Keywords: process calculi, session types, concurrent programming, Scala}
}
Document
DOI: 10.4230/LIPIcs.ECOOP.2017.24
A Linear Decomposition of Multiparty Sessions for Safe Distributed Programming

Authors: Alceste Scalas, Ornela Dardha, Raymond Hu, and Nobuko Yoshida

Published in: LIPIcs, Volume 74, 31st European Conference on Object-Oriented Programming (ECOOP 2017)

Abstract
Multiparty Session Types (MPST) is a typing discipline for message-passing distributed processes that can ensure properties such as absence of communication errors and deadlocks, and protocol conformance. Can MPST provide a theoretical foundation for concurrent and distributed programming in "mainstream" languages? We address this problem by (1) developing the first encoding of a full-fledged multiparty session pi-calculus into linear pi-calculus, and (2) using the encoding as the foundation of a practical toolchain for safe multiparty programming in Scala. Our encoding is type-preserving and operationally sound and complete. Crucially, it keeps the distributed choreographic nature of MPST, illuminating that the safety properties of multiparty sessions can be precisely represented with a decomposition into binary linear channels. Previous works have only studied the relation between (limited) multiparty and binary sessions via centralised orchestration means. We exploit these results to implement an automated generation of Scala APIs for multiparty sessions, abstracting existing libraries for binary communication channels. This allows multiparty systems to be safely implemented over binary message transports, as commonly found in practice. Our implementation is the first to support distributed multiparty delegation: our encoding yields it for free, via existing mechanisms for binary delegation.
Cite as

Alceste Scalas, Ornela Dardha, Raymond Hu, and Nobuko Yoshida. A Linear Decomposition of Multiparty Sessions for Safe Distributed Programming. In 31st European Conference on Object-Oriented Programming (ECOOP 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 74, pp. 24:1-24:31, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2017)

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@InProceedings{scalas_et_al:LIPIcs.ECOOP.2017.24,
  author =	{Scalas, Alceste and Dardha, Ornela and Hu, Raymond and Yoshida, Nobuko},
  title =	{{A Linear Decomposition of Multiparty Sessions for Safe Distributed Programming}},
  booktitle =	{31st European Conference on Object-Oriented Programming (ECOOP 2017)},
  pages =	{24:1--24:31},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-035-4},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{74},
  editor =	{M\"{u}ller, Peter},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2017.24},
  URN =		{urn:nbn:de:0030-drops-72637},
  doi =		{10.4230/LIPIcs.ECOOP.2017.24},
  annote =	{Keywords: process calculi, session types, concurrent programming, Scala}
}
Document
DOI: 10.4230/DagRep.7.1.158
Theory and Applications of Behavioural Types (Dagstuhl Seminar 17051)

Authors: Simon Gay, Vasco T. Vasconcelos, Philip Wadler, and Nobuko Yoshida

Published in: Dagstuhl Reports, Volume 7, Issue 1 (2017)

Abstract
This report documents the programme and the outcomes of Dagstuhl Seminar 17051 "Theory and Applications of Behavioural Types". Behavioural types describe the dynamic aspects of programs, in contrast to data types, which describe the fixed structure of data. Perhaps the most well-known form of behavioural types is session types, which are type-theoretic specifications of communication protocols. More generally, behavioural types include typestate systems, which specify state-dependent availability of operations; choreographies, which specify collective communication behaviour; and behavioural contracts. In recent years, research activity in behavioural types has increased dramatically, in both theoretical and practical directions. Theoretical work has explored new relationships between established behavioural type systems and areas such as linear logic, automata theory, process calculus testing theory, dependent type theory, and model-checking. On the practical side, there are several implementations of programming languages, programming language extensions, software development tools, and runtime monitoring systems, which are becoming mature enough to apply to real-world case studies. The seminar brought together researchers from the established, largely European, research community in behavioural types, and other participants from outside Europe and from related research topics such as effect systems and actor-based languages. The questions that we intended to explore included: - How can we understand the relationships between the foundations of session types in terms of linear logic, automata, denotational models, and other type theories? - How can the scope and applicability of behavioural types be increased by incorporating ideas and approaches from gradual typing and dependent type theory? - What is the relationship, in terms of expressivity and tractability, between behavioural types and other verification techniques such as model-checking? - What are the theoretical and practical obstacles to delivering behavioural types to software developers in a range of mainstream programming languages? - What are the advantages and disadvantages of incorporating behavioural types into standard programming languages or designing new languages directly based on the foundations of session types? - How can we evaluate the effectiveness of behavioural types in programming languages and software development?
Cite as

Simon Gay, Vasco T. Vasconcelos, Philip Wadler, and Nobuko Yoshida. Theory and Applications of Behavioural Types (Dagstuhl Seminar 17051). In Dagstuhl Reports, Volume 7, Issue 1, pp. 158-189, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2017)

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@Article{gay_et_al:DagRep.7.1.158,
  author =	{Gay, Simon and Vasconcelos, Vasco T. and Wadler, Philip and Yoshida, Nobuko},
  title =	{{Theory and Applications of Behavioural Types (Dagstuhl Seminar 17051)}},
  pages =	{158--189},
  journal =	{Dagstuhl Reports},
  ISSN =	{2192-5283},
  year =	{2017},
  volume =	{7},
  number =	{1},
  editor =	{Gay, Simon and Vasconcelos, Vasco T. and Wadler, Philip and Yoshida, Nobuko},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DagRep.7.1.158},
  URN =		{urn:nbn:de:0030-drops-72497},
  doi =		{10.4230/DagRep.7.1.158},
  annote =	{Keywords: Behavioural Types, Programming Languages, Runtime Verification, Type Systems}
}
Document
DOI: 10.4230/LIPIcs.ECOOP.2016.21
Lightweight Session Programming in Scala

Authors: Alceste Scalas and Nobuko Yoshida

Published in: LIPIcs, Volume 56, 30th European Conference on Object-Oriented Programming (ECOOP 2016)

Abstract
Designing, developing and maintaining concurrent applications is an error-prone and time-consuming task; most difficulties arise because compilers are usually unable to check whether the inputs/outputs performed by a program at runtime will adhere to a given protocol specification. To address this problem, we propose lightweight session programming in Scala: we leverage the native features of the Scala type system and standard library, to introduce (1) a representation of session types as Scala types, and (2) a library, called lchannels, with a convenient API for session-based programming, supporting local and distributed communication. We generalise the idea of Continuation-Passing Style Protocols (CPSPs), studying their formal relationship with session types. We illustrate how session programming can be carried over in Scala: how to formalise a communication protocol, and represent it using Scala classes and lchannels, letting the compiler help spotting protocol violations. We attest the practicality of our approach with a complex use case, and evaluate the performance of lchannels with a series of benchmarks.
Cite as

Alceste Scalas and Nobuko Yoshida. Lightweight Session Programming in Scala. In 30th European Conference on Object-Oriented Programming (ECOOP 2016). Leibniz International Proceedings in Informatics (LIPIcs), Volume 56, pp. 21:1-21:28, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2016)

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@InProceedings{scalas_et_al:LIPIcs.ECOOP.2016.21,
  author =	{Scalas, Alceste and Yoshida, Nobuko},
  title =	{{Lightweight Session Programming in Scala}},
  booktitle =	{30th European Conference on Object-Oriented Programming (ECOOP 2016)},
  pages =	{21:1--21:28},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-014-9},
  ISSN =	{1868-8969},
  year =	{2016},
  volume =	{56},
  editor =	{Krishnamurthi, Shriram and Lerner, Benjamin S.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2016.21},
  URN =		{urn:nbn:de:0030-drops-61156},
  doi =		{10.4230/LIPIcs.ECOOP.2016.21},
  annote =	{Keywords: session types, Scala, concurrency}
}
Document
DOI: 10.4230/DARTS.2.1.11
Lightweight Session Programming in Scala (Artifact)

Authors: Alceste Scalas and Nobuko Yoshida

Published in: DARTS, Volume 2, Issue 1, Special Issue of the 30th European Conference on Object-Oriented Programming (ECOOP 2016)

Abstract
In the paper "Lightweight Session Programming in Scala", we introduce a "lightweight" integration of session types in the Scala programming language, based on (1) a formal type-level encoding, and (2) a library implementation of linear I/O channels, called lchannels, providing a convenient API for session-based programming, and supporting both local and distributed communication. This artifact is the source code of lchannels, with all the examples and benchmarks discussed in the paper.
Cite as

Alceste Scalas and Nobuko Yoshida. Lightweight Session Programming in Scala (Artifact). In Special Issue of the 30th European Conference on Object-Oriented Programming (ECOOP 2016). Dagstuhl Artifacts Series (DARTS), Volume 2, Issue 1, pp. 11:1-11:2, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2016)

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@Article{scalas_et_al:DARTS.2.1.11,
  author =	{Scalas, Alceste and Yoshida, Nobuko},
  title =	{{Lightweight Session Programming in Scala (Artifact)}},
  pages =	{11:1--11:2},
  journal =	{Dagstuhl Artifacts Series},
  ISSN =	{2509-8195},
  year =	{2016},
  volume =	{2},
  number =	{1},
  editor =	{Scalas, Alceste and Yoshida, Nobuko},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DARTS.2.1.11},
  URN =		{urn:nbn:de:0030-drops-61327},
  doi =		{10.4230/DARTS.2.1.11},
  annote =	{Keywords: session types, Scala, concurrency}
}
Document
DOI: 10.4230/LIPIcs.FSTTCS.2015.560
On the Expressiveness of Multiparty Sessions

Authors: Romain Demangeon and Nobuko Yoshida

Published in: LIPIcs, Volume 45, 35th IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS 2015)

Abstract
This paper explores expressiveness of asynchronous multiparty sessions. We model the behaviours of endpoint implementations in several ways: (i) by the existence of different buffers and queues used to store messages exchanged asynchronously, (ii) by the ability for an endpoint to lightly reconfigure his behaviour at runtime (flexibility), (iii) by the presence of explicit parallelism or interruptions (exceptional actions) in endpoint behaviour. For a given protocol we define several denotations, based on traces of events, corresponding to the different implementations and compare them.
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Romain Demangeon and Nobuko Yoshida. On the Expressiveness of Multiparty Sessions. In 35th IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS 2015). Leibniz International Proceedings in Informatics (LIPIcs), Volume 45, pp. 560-574, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2015)

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@InProceedings{demangeon_et_al:LIPIcs.FSTTCS.2015.560,
  author =	{Demangeon, Romain and Yoshida, Nobuko},
  title =	{{On the Expressiveness of Multiparty Sessions}},
  booktitle =	{35th IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS 2015)},
  pages =	{560--574},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-97-2},
  ISSN =	{1868-8969},
  year =	{2015},
  volume =	{45},
  editor =	{Harsha, Prahladh and Ramalingam, G.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FSTTCS.2015.560},
  URN =		{urn:nbn:de:0030-drops-56217},
  doi =		{10.4230/LIPIcs.FSTTCS.2015.560},
  annote =	{Keywords: concurrency, message-passing, session, asynchrony, expressiveness}
}
Document
DOI: 10.4230/LIPIcs.CONCUR.2015.283
Meeting Deadlines Together

Authors: Laura Bocchi, Julien Lange, and Nobuko Yoshida

Published in: LIPIcs, Volume 42, 26th International Conference on Concurrency Theory (CONCUR 2015)

Abstract
This paper studies safety, progress, and non-zeno properties of Communicating Timed Automata (CTAs), which are timed automata (TA) extended with unbounded communication channels, and presents a procedure to build timed global specifications from systems of CTAs. We define safety and progress properties for CTAs by extending properties studied in communicating finite-state machines to the timed setting. We then study non-zenoness for CTAs; our aim is to prevent scenarios in which the participants have to execute an infinite number of actions in a finite amount of time. We propose sound and decidable conditions for these properties, and demonstrate the practicality of our approach with an implementation and experimental evaluations of our theory.
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Laura Bocchi, Julien Lange, and Nobuko Yoshida. Meeting Deadlines Together. In 26th International Conference on Concurrency Theory (CONCUR 2015). Leibniz International Proceedings in Informatics (LIPIcs), Volume 42, pp. 283-296, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2015)

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@InProceedings{bocchi_et_al:LIPIcs.CONCUR.2015.283,
  author =	{Bocchi, Laura and Lange, Julien and Yoshida, Nobuko},
  title =	{{Meeting Deadlines Together}},
  booktitle =	{26th International Conference on Concurrency Theory (CONCUR 2015)},
  pages =	{283--296},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-91-0},
  ISSN =	{1868-8969},
  year =	{2015},
  volume =	{42},
  editor =	{Aceto, Luca and de Frutos Escrig, David},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CONCUR.2015.283},
  URN =		{urn:nbn:de:0030-drops-53838},
  doi =		{10.4230/LIPIcs.CONCUR.2015.283},
  annote =	{Keywords: timed automata, multiparty session types, global specification}
}
Document
DOI: 10.4230/LIPIcs.CONCUR.2015.398
Characteristic Bisimulation for Higher-Order Session Processes

Authors: Dimitrios Kouzapas, Jorge A. Pérez, and Nobuko Yoshida

Published in: LIPIcs, Volume 42, 26th International Conference on Concurrency Theory (CONCUR 2015)

Abstract
Characterising contextual equivalence is a long-standing issue for higher-order (process) languages. In the setting of a higher-order pi-calculus with sessions, we develop characteristic bisimilarity, a typed bisimilarity which fully characterises contextual equivalence. To our knowledge, ours is the first characterisation of its kind. Using simple values inhabiting (session) types, our approach distinguishes from untyped methods for characterising contextual equivalence in higher-order processes: we show that observing as inputs only a precise finite set of higher-order values suffices to reason about higher-order session processes. We demonstrate how characteristic bisimilarity can be used to justify optimisations in session protocols with mobile code communication.
Cite as

Dimitrios Kouzapas, Jorge A. Pérez, and Nobuko Yoshida. Characteristic Bisimulation for Higher-Order Session Processes. In 26th International Conference on Concurrency Theory (CONCUR 2015). Leibniz International Proceedings in Informatics (LIPIcs), Volume 42, pp. 398-411, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2015)

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@InProceedings{kouzapas_et_al:LIPIcs.CONCUR.2015.398,
  author =	{Kouzapas, Dimitrios and P\'{e}rez, Jorge A. and Yoshida, Nobuko},
  title =	{{Characteristic Bisimulation for Higher-Order Session Processes}},
  booktitle =	{26th International Conference on Concurrency Theory (CONCUR 2015)},
  pages =	{398--411},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-91-0},
  ISSN =	{1868-8969},
  year =	{2015},
  volume =	{42},
  editor =	{Aceto, Luca and de Frutos Escrig, David},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CONCUR.2015.398},
  URN =		{urn:nbn:de:0030-drops-53659},
  doi =		{10.4230/LIPIcs.CONCUR.2015.398},
  annote =	{Keywords: Behavioural equivalences, session types, higher-order process calculi}
}
Document
DOI: 10.4230/LIPIcs.CONCUR.2015.412
Multiparty Session Types as Coherence Proofs

Authors: Marco Carbone, Fabrizio Montesi, Carsten Schürmann, and Nobuko Yoshida

Published in: LIPIcs, Volume 42, 26th International Conference on Concurrency Theory (CONCUR 2015)

Abstract
We propose a Curry-Howard correspondence between a language for programming multiparty sessions and a generalisation of Classical Linear Logic (CLL). In this framework, propositions correspond to the local behaviour of a participant in a multiparty session type, proofs to processes, and proof normalisation to executing communications. Our key contribution is generalising duality, from CLL, to a new notion of n-ary compatibility, called coherence. Building on coherence as a principle of compositionality, we generalise the cut rule of CLL to a new rule for composing many processes communicating in a multiparty session. We prove the soundness of our model by showing the admissibility of our new rule, which entails deadlock-freedom via our correspondence.
Cite as

Marco Carbone, Fabrizio Montesi, Carsten Schürmann, and Nobuko Yoshida. Multiparty Session Types as Coherence Proofs. In 26th International Conference on Concurrency Theory (CONCUR 2015). Leibniz International Proceedings in Informatics (LIPIcs), Volume 42, pp. 412-426, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2015)

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@InProceedings{carbone_et_al:LIPIcs.CONCUR.2015.412,
  author =	{Carbone, Marco and Montesi, Fabrizio and Sch\"{u}rmann, Carsten and Yoshida, Nobuko},
  title =	{{Multiparty Session Types as Coherence Proofs}},
  booktitle =	{26th International Conference on Concurrency Theory (CONCUR 2015)},
  pages =	{412--426},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-91-0},
  ISSN =	{1868-8969},
  year =	{2015},
  volume =	{42},
  editor =	{Aceto, Luca and de Frutos Escrig, David},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CONCUR.2015.412},
  URN =		{urn:nbn:de:0030-drops-53661},
  doi =		{10.4230/LIPIcs.CONCUR.2015.412},
  annote =	{Keywords: Programming languages, Type systems, Session Types, Linear Logic}
}
Document
DOI: 10.4230/OASIcs.ICCSW.2014.50
Calculating communication costs with Sessions Types and Sizes

Authors: Juliana Franco, Sophia Drossopoulou, and Nobuko Yoshida

Published in: OASIcs, Volume 43, 2014 Imperial College Computing Student Workshop

Abstract
We present a small object-oriented language with communication primitives. The language allows the assignment of binary session types to communication channels in order to govern the interaction between different objects and to statically calculate communication costs. Class declarations are annotated with size information in order to determine the cost of sending and receiving objects. This paper describes our first steps in the creation of a session-based, object-oriented language for communication optimization purposes.
Cite as

Juliana Franco, Sophia Drossopoulou, and Nobuko Yoshida. Calculating communication costs with Sessions Types and Sizes. In 2014 Imperial College Computing Student Workshop. Open Access Series in Informatics (OASIcs), Volume 43, pp. 50-57, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2014)

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@InProceedings{franco_et_al:OASIcs.ICCSW.2014.50,
  author =	{Franco, Juliana and Drossopoulou, Sophia and Yoshida, Nobuko},
  title =	{{Calculating communication costs with Sessions Types and Sizes}},
  booktitle =	{2014 Imperial College Computing Student Workshop},
  pages =	{50--57},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-76-7},
  ISSN =	{2190-6807},
  year =	{2014},
  volume =	{43},
  editor =	{Neykova, Rumyana and Ng, Nicholas},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ICCSW.2014.50},
  URN =		{urn:nbn:de:0030-drops-47739},
  doi =		{10.4230/OASIcs.ICCSW.2014.50},
  annote =	{Keywords: Session types, communication, object-oriented, multicore}
}
Document
DOI: 10.4230/LIPIcs.FSTTCS.2010.338
Global Escape in Multiparty Sessions

Authors: Sara Capecchi, Elena Giachino, and Nobuko Yoshida

Published in: LIPIcs, Volume 8, IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS 2010)

Abstract
This paper proposes a global escape mechanism which can handle unexpected or unwanted conditions changing the default execution of distributed communicational flows, preserving compatibility of the multiparty conversations. Our escape is realised by a collection of asynchronous local exceptions which can be thrown at any stage of the communication and to any subsets of participants in a multiparty session. This flexibility enables to model complex exceptions such as criss-crossing global interactions and fault tolerance for distributed cooperating threads. Guided by multiparty session types, our semantics automatically provides an efficient termination algorithm for global escapes with low complexity of exception messages.
Cite as

Sara Capecchi, Elena Giachino, and Nobuko Yoshida. Global Escape in Multiparty Sessions. In IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS 2010). Leibniz International Proceedings in Informatics (LIPIcs), Volume 8, pp. 338-351, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2010)

Copy BibTex To Clipboard

@InProceedings{capecchi_et_al:LIPIcs.FSTTCS.2010.338,
  author =	{Capecchi, Sara and Giachino, Elena and Yoshida, Nobuko},
  title =	{{Global Escape in Multiparty Sessions}},
  booktitle =	{IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS 2010)},
  pages =	{338--351},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-23-1},
  ISSN =	{1868-8969},
  year =	{2010},
  volume =	{8},
  editor =	{Lodaya, Kamal and Mahajan, Meena},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FSTTCS.2010.338},
  URN =		{urn:nbn:de:0030-drops-28760},
  doi =		{10.4230/LIPIcs.FSTTCS.2010.338},
  annote =	{Keywords: escape mechanism, exception handling, multiparty communication}
}
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