Manifest Contracts for Datatypes

SekiyamaTaro,; NishidaYuki,; Igarashi, Atsushi

doi:10.1145/2775051.2676996

Cited by 5 publications

(11 citation statements)

References 58 publications

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“…The rules irrelevant to intersection types ((RC-Nat), (RC-Bool), (RC-Forget), (RC-Delay), (RC-Arrow), (RC-Waiting), (RC-Activate), (RC-Succeed), and (RC-Fail)) are adopted from Sekiyama et al [26], but there is one difference about (RC-Delay) and (RC-Arrow). In the original definition delayed checking is done by using lambda abstractions, that is,…”

Section: Operational Semantics Of Pcfv∆ Hmentioning

confidence: 99%

“…A large part of the compile-time rules are adapted from PCF, Sekiyama et al [26], and Liquori and Stolze [17]. Here we explain some notable rules.…”

Section: Type System Of Pcfv∆ Hmentioning

confidence: 99%

“…The premise σ = τ of the rule (T-Cast) for casts requires the essences of the source and target types to agree. It amounts to checking the two types σ and τ are compatible [26].…”

Section: Type System Of Pcfv∆ Hmentioning

confidence: 99%

“…The run-time rules are from Sekiyama et al [26] with one extra rule (T-Delayed). The rule (T-Delayed) is for a delayed checking for function types, which restrict the source type so that it respects the evaluation relation (there is no evaluation rule for a delayed checking in which source type is a refinement type), and inherits the condition on the source and target types from (T-Cast).…”

Section: Type System Of Pcfv∆ Hmentioning

confidence: 99%

“…So, the system does not guarantee the absence of contract violations statically, but it guarantees that the result of successful execution satisfies the predicate of a refinement type in the program's type. This property follows subject reduction and a property called value inversion [26]-if a value V has a type {x:τ | M }, then the expression obtained by substituting V for x in M is always evaluated into true.…”

Section: Introductionmentioning

confidence: 99%

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Manifest Contracts with Intersection Types

Nishida

Igarashi

2019

Programming Languages and Systems

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We present a manifest contract system PCFv∆H with intersection types. A manifest contract system is a typed functional calculus in which software contracts are integrated into a refinement type system and consistency of contracts is checked by combination of compile-and run-time type checking. Intersection types naturally arise when a contract is expressed by a conjunction of smaller contracts. Run-time contract checking for conjunctive higher-order contracts in an untyped language has been studied but our typed setting poses an additional challenge due to the fact that an expression of an intersection type τ1 ∧ τ2 may have to perform different run-time checking whether it is used as τ1 or τ2. We build PCFv∆H on top of the ∆-calculus, a Church-style intersection type system by Liquori and Stolze. In the ∆-calculus, a canonical expression of an intersection type is a strong pair, whose elements are the same expressions except for type annotations. To address the challenge above, we relax strong pairs so that expressions in a pair are the same except for type annotations and casts, which are a construct for run-time checking. We give a formal definition of PCFv∆H and show its basic properties as a manifest contract system: preservation, progress, and value inversion. Furthermore, we show that run-time checking does not affect essential computation.

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Section: Operational Semantics Of Pcfv∆ Hmentioning

confidence: 99%

“…A large part of the compile-time rules are adapted from PCF, Sekiyama et al [26], and Liquori and Stolze [17]. Here we explain some notable rules.…”

Section: Type System Of Pcfv∆ Hmentioning

confidence: 99%

“…The premise σ = τ of the rule (T-Cast) for casts requires the essences of the source and target types to agree. It amounts to checking the two types σ and τ are compatible [26].…”

Section: Type System Of Pcfv∆ Hmentioning

confidence: 99%

Section: Type System Of Pcfv∆ Hmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Manifest Contracts with Intersection Types

Nishida

Igarashi

2019

Programming Languages and Systems

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Space-Efficient Latent Contracts

Greenberg

2019

Lecture Notes in Computer Science

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Standard higher-order contract monitoring breaks tail recursion and leads to space leaks that can change a program's asymptotic complexity; space-efficiency restores tail recursion and bounds the amount of space used by contracts. Space-efficient contract monitoring for contracts enforcing simple type disciplines (a/k/a gradual typing) is well studied. Prior work establishes a space-efficient semantics for manifest contracts without dependency [11]; we adapt that work to a latent calculus with dependency. We guarantee space efficiency when no dependency is used; we cannot generally guarantee space efficiency when dependency is used, but instead offer a framework for making such programs space efficient on a case-by-case basis.

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Foundations of dependent interoperability

Dagand¹,

Tabareau²,

Tanter³

2018

J. Funct. Prog.

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Full-spectrum dependent types promise to enable the development of correct-by-construction software. However, even certified software needs to interact with simply-typed or untyped programs, be it to perform system calls, or to use legacy libraries. Trading static guarantees for runtime checks, the dependent interoperability framework provides a mechanism by which simply-typed values can safely be coerced to dependent types and, conversely, dependently-typed programs can defensively be exported to a simply-typed application. In this article, we give a semantic account of dependent interoperability. Our presentation relies on and is guided by a pervading notion of type equivalence, whose importance has been emphasized in recent work on homotopy type theory. Specifically, we develop the notions of type-theoretic partial Galois connections as a key foundation for dependent interoperability, which accounts for the partiality of the coercions between types. We explore the applicability of both type-theoretic Galois connections and anticonnections in the setting of dependent interoperability. A partial Galois connection enforces a translation of dependent types to runtime checks that are both sound and complete with respect to the invariants encoded by dependent types. Conversely, picking an anticonnection instead lets us induce weaker, sound conditions that can amount to more efficient runtime checks.Our framework is developed in Coq; it is thus constructive and verified in the strictest sense of the terms. Using our library, users can specify domain-specific partial connections between data structures. Our library then takes care of the (sometimes, heavy) lifting that leads to interoperable programs. It thus becomes possible, as we shall illustrate, to internalize and hand-tune the extraction of dependently-typed programs to interoperable OCaml programs within Coq itself.

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Manifest Contracts for Datatypes

Cited by 5 publications

References 58 publications

Manifest Contracts with Intersection Types

Manifest Contracts with Intersection Types

Space-Efficient Latent Contracts

Foundations of dependent interoperability

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