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2021 4th International Conference on Blockchain Technology and Applications

作者： Wei Ke Ka-Hou Chan School of Applied Sciences Macao Polytechnic Institute Macao

ISBN: (纸本)9781450387460

Subtyping and multiple inheritance are the essential features of oo and component-based programming languages, in particular with the presence of interfaces and contracts. More general, the composability of these constructs admitting the subtype relation powers the reusability, modular, flexibility and reliability of oo-based systems. While nominal classes allow annotation of user intention to the types, operations on interfaces and contracts naturally result structural constructs. Structural types are also necessary if we need the types to have value-semantics, so that they can be transferred around in distributed systems. Building a type system that allows the coexistence of nominal and structural classes, while maintaining the usual subtype relation is critical and challenging. We present a subtyping scheme that encodes a class to a directed and edge-labeled graph, which has the convenience to handle recursive types. The names of a class and its superclasses are encoded as tags to label the edges of the graph, turning the nominal construct into a structural one. This encoding allows us to unify the handling of class relations into graph relations. We define the class representation, canonical form, value-identity and subtype relation in the notion of graphs, and justify our subtyping scheme in the cases of multiple inheritance, class intersection and union. Our scheme is general, easy to implement and compatible with most of the existing oo type systems, providing a solid base for further oo language and tool development.

关键词： nominal subtyping recursive type class graph type equivalence intersection type distributed programming structural subtyping union type object-oriented language subtyping multiple inheritance

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A Framework for Flexible Program Evolution and Verification of Distributed Systems 1

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7th International Conference on Model-Driven Engineering and Software Development (MODELSWARD)

作者： Owe, Olaf Fazeldehkordi, Elahe Lin, Jia-Chun Univ Oslo Dept Informat Oslo Norway NTNU Gjovik Dept Informat Secur & Commun Technol Gjovik Norway Univ Oslo Dept Technol Syst Oslo Norway

ISBN: (数字)9783030378738

ISBN: (纸本)9783030378738;9783030378721

Program evolution may reveal bad design decisions, misunderstandings, erroneous code, or erroneous specifications, because problems made early in the design of a system may not be discovered until much later in the life-time of the system. Non-trivial changes of old code may be necessary. Flexibility in making such changes is essential, especially in a distributed setting where the system components are updated independently. In this setting re-verification is challenging. We consider flexibility with respect to what changes can be made as well as what can be efficiently reverified. In this paper we propose a flexible framework for modeling and evolution of distributed systems. It supports unrestricted modifications in such systems, both in code and specifications, and with support of verification and re-verification. We consider on the setting of concurrent and object-oriented distributed programs, and introduce a core high-level modeling language supporting active objects. We allow multiple inheritance because it gives added flexibility during evolution, allowing a wider class of software changes. To avoid undesired effects of multiple inheritance, we apply a healthy binding strategy. We prove that the framework supports Modification Independence and Hierarchy Independence, which requires healthy binding. We demonstrate that our framework can deal with verification of software changes that are not possible in comparable frameworks.

关键词： Program evolution Program reasoning Software changes multiple inheritance Healthy binding Active objects Concurrency Re-verification Evolution flexibility Modification independence Hierarchy independence

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Efficient Fail-Fast Dynamic Subtype Checking 11

Efficient Fail-Fast Dynamic Subtype Checking

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11th ACM SIGPLAN International Workshop on Virtual Machines and Intermediate Languages (VMIL)

作者： Padhye, Rohan Sen, Koushik Univ Calif Berkeley Berkeley CA 94720 USA

ISBN: (纸本)9781450369879

We address the problem of dynamically checking if an instance of class S is also an instance of class T. Researchers have designed various strategies to perform constant-time subtype tests. Yet, well-known production implementations degrade to linear search in the worst case, in order to achieve other goals such as constant space and/or efficient dynamic class loading. The fast path is usually optimized for subtype tests that succeed. However, in workloads where dynamic type tests are common, such as Scala's pattern matching and LLVM compiler passes, we observe that 74%-93% of dynamic subtype tests return a negative result. We thus propose a scheme for fail-fast dynamic subtype checking. In the compiled version of each class, we store a fixed-width bloom filter, which combines randomly generated type identifiers for all its transitive supertypes. At run-time, the bloom filters enable fast refutation of dynamic subtype tests with high probability. If such a refutation cannot be made, the scheme falls back to conventional techniques. This scheme works with multiple inheritance, separate compilation, and dynamic class loading. A prototype implementation of fail-fasts in the JVM provides 1.44x-2.74x speedup over HotSpot's native instance of, on micro-benchmarks where worst-case behavior is likely.

关键词： object-oriented programming dynamic casts multiple inheritance bloom filters

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Classless Java 2016

Classless Java

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15th ACM International Conference on Generative Programming - Concepts and Experiences (GPCE)

作者： Wang, Yanlin Zhang, Haoyuan Oliveira, Bruno C. D. S. Servetto, Marco Univ Hong Kong Hong Kong Hong Kong Peoples R China Victoria Univ Wellington Wellington New Zealand

ISBN: (纸本)9781450344463

This paper presents an OO style without classes, which we call interface-based object-oriented programming (IB). IB is a natural extension of closely related ideas such as traits. Abstract state operations provide a new way to deal with state, which allows for flexibility not available in classbased languages. In IB state can be type-refined in subtypes. The combination of a purely IB style and type-refinement enables powerful idioms using multiple inheritance and state. To introduce IB to programmers we created Classless Java: an embedding of IB directly into Java. Classless Java uses annotation processing for code generation and relies on new features of Java 8 for interfaces. The code generation techniques used in Classless Java have interesting properties, including guarantees that the generated code is type-safe and good integration with IDEs. Usefulness of IB and Classless Java is shown with examples and case studies.

关键词： Interface-based programming multiple inheritance code generation

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Incremental reasoning with lazy behavioral subtyping for multiple inheritance

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SCIENCE OF COMPUTER PROGRAMMING 2011年第10期76卷 915-941页

作者： Dovland, Johan Johnsen, Einar Broch Owe, Olaf Steffen, Martin Univ Oslo Dept Informat N-0316 Oslo Norway

Object-orientation supports code reuse and incremental programming. multiple inheritance increases the possibilities for code reuse, but complicates the binding of method calls and thereby program analysis. Behavioral subtyping allows program analysis under an open world assumption;i.e., under the assumption that class hierarchies are extensible. However, method redefinition is severely restricted by behavioral subtyping, and multiple inheritance may lead to conflicting restrictions from independently designed superclasses. This paper presents a more liberal approach to incremental reasoning for multiple inheritance under an open world assumption. The approach, based on lazy behavioral subtyping, is well-suited for multiple inheritance, as it incrementally imposes context-dependent behavioral constraints on new subclasses. We first present the approach for a simple language and show how incremental reasoning can be combined with flexible code reuse. Then this language is extended with a hierarchy of interface types which is independent of the class hierarchy. In this setting, flexible code reuse can be combined with modular reasoning about external calls in the sense that each class is analyzed only once. We formalize the approach as a calculus and show soundness for both languages. (C) 2010 Elsevier B.V. All rights reserved.

关键词： Lazy behavioral subtyping Object orientation multiple inheritance Late binding Proof systems Code reuse Method redefinition Incremental reasoning

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Metamodeling semantics of multiple inheritance

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SCIENCE OF COMPUTER PROGRAMMING 2011年第7期76卷 555-586页

作者： Ducournau, Roland Privat, Jean LIRMM CNRS F-34000 Montpellier France Univ Montpellier 2 F-34000 Montpellier France Univ Quebec Montreal Dep Informat Montreal PQ H2X 3Y7 Canada

inheritance provides object-oriented programming with much of its great reusability power. When inheritance is single, its specifications are simple and everybody roughly agrees on them. In contrast, multiple inheritance yields ambiguities that have prompted long-standing debates, and no two languages agree on its specifications. In this paper, we present a semantics of multiple inheritance based on metamodeling. A metamodel is proposed which distinguishes the "identity" of properties from their "values" or "implementations". It yields a clear separation between syntactic and semantic conflicts. The former can be solved in any language at the expense of a common syntactic construct, namely full name qualification. However, semantic conflicts require a programmer's decision, and the programming language must help the programmer to some extent. This paper surveys the approach based on linearizations, which has been studied in depth, and proposes some extensions. As it turns out that only static typing takes full advantage of the metamodel, the interaction between multiple inheritance and static typing is also considered, especially in the context of virtual types. The solutions proposed by the various languages with multiple inheritance are compared with the metamodel results. Throughout the paper, difficulties encountered under the open-world assumption are stressed. (C) 2010 Elsevier B.V. All rights reserved.

关键词： Object-oriented programming multiple inheritance Metamodeling Redefinition Linearization Open-world assumption Static typing Virtual types

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Type Checking Modular multiple Dispatch with Parametric Polymorphism and multiple inheritance

Type Checking Modular Multiple Dispatch with Parametric Poly...

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2011 ACM International Conference on Object Oriented Programming Systems Languages and Applications

作者： Allen, Eric Hilburn, Justin Kilpatrick, Scott Luchangco, Victor Ryu, Sukyoung Chase, David Steele, Guy L., Jr. Univ Texas Austin Austin TX 78712 USA Korea Adv Inst Sci & Technol Taejon South Korea

ISBN: (纸本)9781450309400

In previous work, we presented rules for defining overloaded functions that ensure type safety under symmetric multiple dispatch in an object-oriented language with multiple inheritance, and we showed how to check these rules without requiring the entire type hierarchy to be known, thus supporting modularity and extensibility. In this work, we extend these rules to a language that supports parametric polymorphism on both classes and functions. In a multiple-inheritance language in which any type may be extended by types in other modules, some overloaded functions that might seem valid are correctly rejected by our rules. We explain how these functions can be permitted in a language that additionally supports an exclusion relation among types, allowing programmers to declare "nominal exclusions" and also implicitly imposing exclusion among different instances of each polymorphic type. We give rules for computing the exclusion relation, deriving many type exclusions from declared and implicit ones. We also show how to check our rules for ensuring the safety of overloaded functions. In particular, we reduce the problem of handling parametric polymorphism to one of determining subtyping relationships among universal and existential types. Our system has been implemented as part of the open-source Fortress compiler.

关键词： Languages object-oriented programming multiple dispatch symmetric dispatch multiple inheritance overloading modularity methods multimethods static types run-time types ilks components separate compilation Fortress meet rule

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Instantiations of POSDCORB: A Framework-Theory-Model Approach

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ADMINISTRATION & SOCIETY 2016年第3期48卷 316-343页

作者： Chalekian, Paul M. Univ Nevada Dept Polit Sci Reno NV 89557 USA Univ Maryland Univ Coll Dept Management & Technol Baltimore MD USA

Challenges have been made to validate classical forms of management. This study facilitates suggestions to view organizational theory from a design perspective. Affirming how Luther Gulick explored design, tests of a construct were used to substantiate POSDCORB as a framework. Integrated within are elements of linguistics and Alexandrian patterns. An instrument development model was used to approximate POSDCORB as it demonstrated acceptable content validity, as well as construct validity and reliability. Having explored a proxy, models were established using multivariate data. The study provides framework-theory-model scenarios, evidence to indicate the adoption of institutions, and element support.

关键词： organizational patterns contingency theory goodness of fit administrative behavior multiple inheritance

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inheritance in Object-Oriented Knowledge Representation 21st

Inheritance in Object-Oriented Knowledge Representation

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21st International Conference on Information and Software Technologies (ICIST)

作者： Terletskyi, Dmytro Taras Shevchenko Natl Univ Kyiv UA-03680 Kiev Ukraine

ISBN: (纸本)9783319247700;9783319247694

This paper contains the consideration of inheritance mechanism in such knowledge representation models as object-oriented programming, frames and object-oriented dynamic networks. In addition, inheritance within representation of vague and imprecise knowledge are also discussed. New types of inheritance, general classification of all known inheritance types and approach, which allows avoiding in many cases problems with exceptions, redundancy and ambiguity within object-oriented dynamic networks and their fuzzy extension, are introduced in the paper. The proposed approach bases on conception of homogeneous and inhomogeneous or heterogeneous class of objects, which allow building of inheritance hierarchy more flexibly and efficiently.

关键词： Single inheritance multiple inheritance Strong inheritance Weak inheritance Full inheritance Partial inheritance

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SystemVerilog-Based Verification Environment Employing multiple inheritance of SystemC

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2010年第5期E93A卷 989-992页

作者： You, Myoung-Keun Song, Gi-Yong Chungbuk Natl Univ Coll Elect & Comp Engn Cheongju South Korea

In this paper, we describe a verification environment which is based on a constrained random layered testbench using SystemVerilog OOP. As SystemVerilog OOP technique does not allow multiple inheritance, we adopt SystemC to design components of a verification environment which employ multiple inheritance. Then SystemC design unit is linked to a SystemVerilog-based verification environment using SystemVerilog DPI and ModelSim macro. Employing multiple inheritance of SystemC makes the design phase of verification environment simple and easy through source code reusability without corruption due to multi-level single inheritance.

关键词： SystemVerilog SystemC verification environment layered-testbench multiple inheritance

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