Distributing intersection and union types with splits and duality (functional pearl)

Huang, Xuejing; Oliveira, Bruno C. d. S.

doi:10.1145/3473594

Cited by 4 publications

(2 citation statements)

References 22 publications

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“…This allows users to write types like "int|string" to represent the union of integer and string. Huang et al 5 listed a group of languages that support union types, including Scala 3 6 , Flow 7 , TypeScript 8 , Ceylon 9 . Apart from them, the cue language 10 , a typed data description language, also contains union types with a set-theoretical interpretation.…”

Section: Related Workmentioning

confidence: 99%

The design of an experimental cloud resource provisioning language

Wang

Zhang²,

Duo³

et al. 2023

Third International Seminar on Artificial Intelligence, Networking, and Information Technology (AINIT 2022)

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As a cornerstone of cloud-native systems, Kubernetes uses YAML, a data description language, to configure resources. However, YAML does not meet the configuration requirements of complex scenarios and has three major problems. First, YAML has no type checking mechanism and therefore data type mismatches cannot be detected during compilation. Second, YAML does not have the ability to reuse data descriptions and there are duplicate code for largescale data. Third, YAML lacks a type merging algorithm that meets the needs of multi-team development in enterprises. This paper implements an experimental cloud resource provisioning language, Hermias, which is based on the functional programming language OCaml. Hermias is used to describe the resource configuration of cloud servers, which solves the above three problems in YAML. The novelty of this work is to propose a type merging algorithm that computes records with common labels by union types and subtyping.

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Section: Related Workmentioning

confidence: 99%

The design of an experimental cloud resource provisioning language

Wang

Zhang²,

Duo³

et al. 2023

Third International Seminar on Artificial Intelligence, Networking, and Information Technology (AINIT 2022)

View full text Add to dashboard Cite

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“…There have been many efforts to eliminate the explicit transitivity rule to obtain an algorithmic formulation [26,31,39]. Compared with the original F + i [7], we employ a different subtyping algorithm design, using splittable types [21]. This approach employs a type-splitting operation (B A C ) that converts a given type A to an equivalent intersection type…”

Section: Technical Challenges and Innovationsmentioning

confidence: 99%

Direct Foundations for Compositional Programming

Fan¹,

Huang²,

Han³

et al. 2022

Preprint

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The recently proposed CP language adopts Compositional Programming: a new modular programming style that solves challenging problems such as the Expression Problem. CP is implemented on top of a polymorphic core language with disjoint intersection types called F + i . The semantics of F + i employs an elaboration to a target language and relies on a sophisticated proof technique to prove the coherence of the elaboration. Unfortunately, the proof technique is technically challenging and hard to scale to many common features, including recursion or impredicative polymorphism. Thus, the original formulation of F + i does not support the two later features, which creates a gap between theory and practice, since CP fundamentally relies on them.This paper presents a new formulation of F + i based on a type-directed operational semantics (TDOS). The TDOS approach was recently proposed to model the semantics of languages with disjoint intersection types (but without polymorphism). Our work shows that the TDOS approach can be extended to languages with disjoint polymorphism and model the full F + i calculus. Unlike the elaboration semantics, which gives the semantics to F + i indirectly via a target language, the TDOS approach gives a semantics to F + i directly. With a TDOS, there is no need for a coherence proof. Instead, we can simply prove that the semantics is deterministic. The proof of determinism only uses simple reasoning techniques, such as straightforward induction, and is able to handle problematic features such as recursion and impredicative polymorphism. This removes the gap between theory and practice and validates the original proofs of correctness for CP. We formalized the TDOS variant of the F + i calculus and all its proofs in the Coq proof assistant.

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MLstruct: principal type inference in a Boolean algebra of structural types

Parreaux

Chau

2022

Proc. ACM Program. Lang.

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Intersection and union types are becoming more popular by the day, entering the mainstream in programming languages like TypeScript and Scala 3. Yet, no language so far has managed to combine these powerful types with principal polymorphic type inference. We present a solution to this problem in MLstruct, a language with subtyped records, equirecursive types, first-class unions and intersections, class-based instance matching, and ML-style principal type inference. While MLstruct is mostly structurally typed, it contains a healthy sprinkle of nominality for classes, which gives it desirable semantics, enabling the expression of a powerful form of extensible variants that does not need row variables. Technically, we define the constructs of our language using conjunction, disjunction, and negation connectives, making sure they form a Boolean algebra, and we show that the addition of a few nonstandard but sound subtyping rules gives us enough structure to derive a sound and complete type inference algorithm. With this work, we hope to foster the development of better type inference for present and future programming languages with expressive subtyping systems.

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Distributing intersection and union types with splits and duality (functional pearl)

Cited by 4 publications

References 22 publications

The design of an experimental cloud resource provisioning language

The design of an experimental cloud resource provisioning language

Direct Foundations for Compositional Programming

MLstruct: principal type inference in a Boolean algebra of structural types

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