Gradual typing for generics

Ina, Lintaro; Igarashi, Atsushi

doi:10.1145/2048066.2048114

Cited by 39 publications

(22 citation statements)

References 36 publications

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“…Gradual typing [Siek and Taha 2006] is a framework to enable seamless code evolution from a fully dynamically typed program to a fully statically typed one within a single language. The notion of gradual typing has been applied to various language features such as objects [Siek and Taha 2007], generics [Ina and Igarashi 2011], effects [Bañados Schwerter et al 2014, ownership [Sergey and Clarke 2012], parametric polymorphism [Ahmed et al 2011;Igarashi et al 2017;Xie et al 2018] and so on. More recently, even methodologies to "gradualize" existing statically typed languages it is appropriate to recover any static type T for y if we are interested only in obtaining a well-typed term because ⋆ ∼ T → T but the evaluation of the resulting term significantly differs depending on the choice for T .…”

Section: Gradual Typingmentioning

confidence: 99%

Dynamic type inference for gradual Hindley–Milner typing

Miyazaki

Sekiyama

Igarashi

2019

Proc. ACM Program. Lang.

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and Cimini study a type inference problem for the ITGL, an implicitly and gradually typed language with let-polymorphism, and develop a sound and complete inference algorithm for it. Soundness and completeness mean that, if the algorithm succeeds, the input term can be translated to a well-typed term of an explicitly typed blame calculus by cast insertion and vice versa. However, in general, there are many possible translations depending on how type variables that were left undecided by static type inference are instantiated with concrete static types. Worse, the translated terms may behave differently-some evaluate to values but others raise blame.In this paper, we propose and formalize a new blame calculus λ DTI B that avoids such divergence as an intermediate language for the ITGL. A main idea is to allow a term to contain type variables (that have not been instantiated during static type inference) and defer instantiation of these type variables to run time. We introduce dynamic type inference (DTI) into the semantics of λ DTI B so that type variables are instantiated along reduction. The DTI-based semantics not only avoids the divergence described above but also is sound and complete with respect to the semantics of fully instantiated terms in the following sense: if the evaluation of a term succeeds (i.e., terminates with a value) in the DTI-based semantics, then there is a fully instantiated version of the term that also succeeds in the explicitly typed blame calculus and vice versa.Finally, we prove the gradual guarantee, which is an important correctness criterion of a gradually typed language, for the ITGL.

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Section: Gradual Typingmentioning

confidence: 99%

Dynamic type inference for gradual Hindley–Milner typing

Miyazaki

Sekiyama

Igarashi

2019

Proc. ACM Program. Lang.

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“…The appeal of gradual typing has inspired the development of gradual approaches to a variety of type disciplines, including objects [14,22,24], ownership types [21], typestates [10,26], and information flow typing [6].…”

Section: Towards Gradual Effect Checkingmentioning

confidence: 99%

“…Its main contribution was to identify the notion of consistency as a key to support the full spectrum of static-to-dynamic typing. Originally developed for functional languages, it has been extended in several directions, including structural objects [22] and generics [14]. Most directly related to this work is the application of the gradual typing principles to other typing disciplines, such as ownership types, typestates, and information flow typing.…”

Section: Related Workmentioning

confidence: 99%

A theory of gradual effect systems

Schwerter

García

Tanter

2014

Proceedings of the 19th ACM SIGPLAN International Conference on Functional Programming

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Effect systems have the potential to help software developers, but their practical adoption has been very limited. We conjecture that this limited adoption is due in part to the difficulty of transitioning from a system where effects are implicit and unrestricted to a system with a static effect discipline, which must settle for conservative checking in order to be decidable. To address this hindrance, we develop a theory of gradual effect checking, which makes it possible to incrementally annotate and statically check effects, while still rejecting statically inconsistent programs. We extend the generic type-and-effect framework of Marino and Millstein with a notion of unknown effects, which turns out to be significantly more subtle than unknown types in traditional gradual typing. We appeal to abstract interpretation to develop and validate the concepts of gradual effect checking. We also demonstrate how an effect system formulated in Marino and Millstein's framework can be automatically extended to support gradual checking.

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“…Gradual typing has been combined with subtyping in a simple object calculus Siek and Taha [23], with a nominal, polymorphic type system Ina and Igarashi [16], with a row polymorphism Takikawa et al [26], and with the polymorphic lambda calculus Ahmed et al [2]. Gradual typing also adopted blame tracking from higher-order contracts Siek and Wadler [24? ], Wadler and Findler [31].…”

Section: Related Workmentioning

confidence: 99%

Typed Lua

Maidl

Mascarenhas

Ierusalimschy

2014

Proceedings of the Workshop on Dynamic Languages and Applications

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Dynamically typed languages trade flexibility and ease of use for safety, while statically typed languages prioritize the early detection of bugs, and provide a better framework for structure large programs. The idea of optional typing is to combine the two approaches in the same language: the programmer can begin development with dynamic types, and migrate to static types as the program matures. The challenge is designing a type system that feels natural to the programmer that is used to programming in a dynamic language.This paper presents the initial design of Typed Lua, an optionally-typed extension of the Lua scripting language. Lua is an imperative scripting language with first class functions and lightweight metaprogramming mechanisms. The design of Typed Lua's type system has a novel combination of features that preserves some of the idioms that Lua programmers are used to, while bringing static type safety to them. We show how the major features of the type system type these idioms with some examples, and discuss some of the design issues we faced.

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Gradual typing for generics

Cited by 39 publications

References 36 publications

Dynamic type inference for gradual Hindley–Milner typing

Dynamic type inference for gradual Hindley–Milner typing

A theory of gradual effect systems

Typed Lua

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