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FeatherTrait: A modest extension of Featherweight Java

Authors:

Arnaud SpiwackAuthors Info & Claims

ACM Transactions on Programming Languages and Systems (TOPLAS), Volume 30, Issue 2

Article No.: 11, Pages 1 - 32

https://doi.org/10.1145/1330017.1330022

Published: 14 March 2008 Publication History

Abstract

In the context of statically typed, class-based languages, we investigate classes that can be extended with trait composition. A trait is a collection of methods without state; it can be viewed as an incomplete stateless class. Traits can be composed in any order, but only make sense when imported by a class that provides state variables and additional methods to disambiguate conflicting names arising between the imported traits. We introduce FeatherTrait Java (FTJ), a conservative extension of the simple lightweight class-based calculus Featherweight Java (FJ) with statically typed traits. In FTJ, classes can be built using traits as basic behavioral bricks; method conflicts between imported traits must be resolved explicitly by the user either by (i) aliasing or excluding method names in traits, or by (ii) overriding explicitly the conflicting methods in the class or in the trait itself. We present an operational semantics with a lookup algorithm, and a sound type system that guarantees that evaluating a well-typed expression never yields a message-not-understood run-time error nor gets the interpreter stuck. We give examples of the increased expressive power of the trait-based inheritance model. The resulting calculus appears to be a good starting point for a rigorous mathematical analysis of typed class-based languages featuring trait-based inheritance.

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Cited By

Damiani FHähnle RKamburjan ELienhardt MPaolini L(2023)Variability modulesJournal of Systems and Software10.1016/j.jss.2022.111510195:COnline publication date: 1-Jan-2023
https://dl.acm.org/doi/10.1016/j.jss.2022.111510
Runge TPotanin AThüm TSchaefer I(2022)Traits: Correctness-by-Construction for FreeFormal Techniques for Distributed Objects, Components, and Systems10.1007/978-3-031-08679-3_9(131-150)Online publication date: 13-Jun-2022
https://dl.acm.org/doi/10.1007/978-3-031-08679-3_9
Racordon DBuchs DLämmel RTratt Lde Lara J(2020)Featherweight Swift: a Core calculus for Swift’s type systemProceedings of the 13th ACM SIGPLAN International Conference on Software Language Engineering10.1145/3426425.3426939(140-154)Online publication date: 16-Nov-2020
https://dl.acm.org/doi/10.1145/3426425.3426939
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Index Terms

FeatherTrait: A modest extension of Featherweight Java
1. Software and its engineering
  1. Software notations and tools
    1. Formal language definitions
      1. Semantics
      2. Syntax
    2. General programming languages
      1. Language features
        Classes and objects
        Inheritance
      2. Language types
        Object oriented languages
2. Theory of computation
  1. Semantics and reasoning
    1. Program constructs
      1. Object oriented constructs
    2. Program semantics

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Published In

cover image ACM Transactions on Programming Languages and Systems

ACM Transactions on Programming Languages and Systems Volume 30, Issue 2

March 2008

217 pages

ISSN:0164-0925

EISSN:1558-4593

DOI:10.1145/1330017

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Copyright © 2008 ACM.

Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. Request permissions from [email protected]

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Publication History

Published: 14 March 2008

Accepted: 01 February 2007

Revised: 01 June 2006

Received: 01 May 2005

Published in TOPLAS Volume 30, Issue 2

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Cited By

Damiani FHähnle RKamburjan ELienhardt MPaolini L(2023)Variability modulesJournal of Systems and Software10.1016/j.jss.2022.111510195:COnline publication date: 1-Jan-2023
https://dl.acm.org/doi/10.1016/j.jss.2022.111510
Runge TPotanin AThüm TSchaefer I(2022)Traits: Correctness-by-Construction for FreeFormal Techniques for Distributed Objects, Components, and Systems10.1007/978-3-031-08679-3_9(131-150)Online publication date: 13-Jun-2022
https://dl.acm.org/doi/10.1007/978-3-031-08679-3_9
Racordon DBuchs DLämmel RTratt Lde Lara J(2020)Featherweight Swift: a Core calculus for Swift’s type systemProceedings of the 13th ACM SIGPLAN International Conference on Software Language Engineering10.1145/3426425.3426939(140-154)Online publication date: 16-Nov-2020
https://dl.acm.org/doi/10.1145/3426425.3426939
Zaytsev VLämmel RTratt Lde Lara J(2020)Software language engineers’ worst nightmareProceedings of the 13th ACM SIGPLAN International Conference on Software Language Engineering10.1145/3426425.3426933(72-85)Online publication date: 16-Nov-2020
https://dl.acm.org/doi/10.1145/3426425.3426933
Gariano IServetto MPotanin AArora H(2019)Iteratively Composing Statically Verified TraitsElectronic Proceedings in Theoretical Computer Science10.4204/EPTCS.299.7299(49-55)Online publication date: 20-Aug-2019
https://doi.org/10.4204/EPTCS.299.7
Inoue HIgarashi A(2019)A type system for first-class layers with inheritance, subtyping, and swappingScience of Computer Programming10.1016/j.scico.2019.03.008Online publication date: Apr-2019
https://doi.org/10.1016/j.scico.2019.03.008
Bettini LDamiani F(2017)XtraitjJournal of Systems and Software10.1016/j.jss.2016.07.035131:C(419-441)Online publication date: 1-Sep-2017
https://dl.acm.org/doi/10.1016/j.jss.2016.07.035
Abdelzad VLethbridge T(2017)Promoting traits into model-driven developmentSoftware and Systems Modeling (SoSyM)10.1007/s10270-015-0505-x16:4(997-1017)Online publication date: 1-Oct-2017
https://dl.acm.org/doi/10.1007/s10270-015-0505-x
Damiani FHähnle RKamburjan ELienhardt M(2017)A Unified and Formal Programming Model for Deltas and TraitsProceedings of the 20th International Conference on Fundamental Approaches to Software Engineering - Volume 1020210.1007/978-3-662-54494-5_25(424-441)Online publication date: 22-Apr-2017
https://dl.acm.org/doi/10.1007/978-3-662-54494-5_25
Wang YZhang HOliveira BServetto M(2016)Classless JavaACM SIGPLAN Notices10.1145/3093335.299323852:3(14-24)Online publication date: 20-Oct-2016
https://dl.acm.org/doi/10.1145/3093335.2993238
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