1,363 research outputs found
Verified Subtyping with Traits and Mixins
Traits allow decomposing programs into smaller parts and mixins are a form of
composition that resemble multiple inheritance. Unfortunately, in the presence
of traits, programming languages like Scala give up on subtyping relation
between objects. In this paper, we present a method to check subtyping between
objects based on entailment in separation logic. We implement our method as a
domain specific language in Scala and apply it on the Scala standard library.
We have verified that 67% of mixins used in the Scala standard library do
indeed conform to subtyping between the traits that are used to build them.Comment: In Proceedings FSFMA 2014, arXiv:1407.195
A Type System for First-Class Layers with Inheritance, Subtyping, and Swapping
Context-Oriented Programming (COP) is a programming paradigm to encourage
modularization of context-dependent software. Key features of COP are
layers---modules to describe context-dependent behavioral variations of a
software system---and their dynamic activation, which can modify the behavior
of multiple objects that have already been instantiated. Typechecking programs
written in a COP language is difficult because the activation of a layer can
even change objects' interfaces. Inoue et al. have informally discussed how to
make JCop, an extension of Java for COP by Appeltauer et al., type-safe.
In this article, we formalize a small COP language called ContextFJ
with its operational semantics and type system and show its type soundness. The
language models main features of the type-safe version of JCop, including
dynamically activated first-class layers, inheritance of layer definitions,
layer subtyping, and layer swapping
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