函数式面向对象语言FOPL的指称语义

函数式面向对象程序设计语言ＦＯＰＬ是笔者设计并实现的一种合成语言，本文在一个全称的抽象域上描述了ＦＯＰＬ语言的指称语义。     

Semantics of plan revision in intelligent agents

In this paper, we give an operational and denotational semantics for a meta-language of the 3APL agent programming language. With this meta-language, various 3APL interpreters can be programmed. We prove equivalence of the operational and denotational semantics. Furthermore, we give an operational semantics for object-level 3APL. Using this semantics, we relate the 3APL meta-language to object-level 3APL by providing a specific interpreter, the semantics of which will prove to be equivalent to object-level 3APL.     

一个并发对象演算

由于缺乏一个为人们接受的描述并发对象系统语义的形式化模型,开发面向对象程序设计语言的开发受到了很大的制约,为了给并发面向对象程序设计定义一个公共的语义框架,人们分别以π演算和ａｃｔｏｒ模型为基础进行了研究。     

广义继承及其在面向对象程序设计语言中的实现*

本文给出一种包含多种继承行为的、非常灵活的代码复用机制——广义继承,通过给出其操作语义和一个支持类间子类型关系确认的类机制．为其在面向对象程序设计语言中的实现奠定了基础．     

过程式语言到函数式语言的抽象方法

本文给出了从过程式程序到函数式程序的转换规则，这些转换规则是从语言的接续指称语义推导出来的，我们考虑了ＧＯＴＯ语句的处理，因此，我们的方法可以处理非结构化程序。由于这些转换规则是从指称语义导出的，其正确性得到了保证。     

Smalltalk－80的指称语义研究

Ｓｍａｌｌｔａｌｋ—８０是原型的面向对象程序设计语言和环境．本文简要地给出了Ｓｍａｌｌｔａｌｋ－８０的形式模型,并基于该模型描述了Ｓｍａｌｌｔａｌｋ—８０的静态和动态指称语义．     

动态模糊逻辑(DFL)程序设计语言的结构化操作语义

动态模糊问题在客观世界中是普遍存在的,作为解决动态模糊问题的理论工具-动态模糊逻辑(DFL)已有十年的研究历史了,为了更有效地解决动态模糊问题,使DFL成为一种切实可实现的逻辑系统,有必要研究设计一种适合解决动态模糊性问题的程序设计语言.仿照监督命令的程序结构,给出动态模糊程序设计语言的结构化操作语义,其内容包括:动态模糊逻辑程序设计语言的抽象语法、动态模糊语义并通过一个简单实例说明其有效性.     

语义转换--直接指称语义到接续指称语义

指称语义分为直接指称语义和接续指称语义,其中后一种语义描述的难度较大,给出了直接指称语义描述到接续指称语义描述的转换方法,这就使得这种语义转换的自动化成为可能．转换算法揭示了直接指称语义与接续指称语义之间的内在关系,同时也提供了写接续指称语义描述的有效方法．当需要检验同一种语言的直接指称语义描述和接续指称语义描述是否等价时,提供的技术是很有用的。     

The VLISP verified Scheme system

The VLISP project has produced a rigorously verified compiler from Scheme to byte codes, and a verified interpreter for the resulting byte codes. The official denotational semantics for Scheme provides the main criterion of correctness. The Wand-Clinger technique was used to prove correctness of the primary compiler step. Then a state machine operational semantics is proved to be faithful to the denotational semantics. The remainder of the implementation is verified by a succession of state machine refinement proofs. These include proofs that garbage collection is a sound implementation strategy, and that a particular garbage collection algorithm is correct.The work reported here was carried out as part of The MITRE Corporation's Technology Program, under funding from Rome Laboratory, Electronic Systems Command, United States Air Force, through contract F19628-89-C-0001. Preparation of this paper was generously supported by The MITRE Corporation.     

Partial ordering models for concurrency can be defined operationally

Labelled rewriting systems are shown to be powerful enough for defining the semantics of concurrent systems in terms of partial orderings of events, even in the presence of non standard operators like N that is not expressible by means of concurrency and sequentialization. This contrasts with Pratt's claim.⁽¹⁾ The main operators proposed by Pratt are used here to construct terms denoting concurrent systems, the behavior of which consists of partially ordered multisets defined operationally.⁽²⁾ Fully abstractness of the denotational semantics as defined in Ref. 1 with respect to the operational one is finally proved.     

接续到直接的指称语义转换

接续和直接指称语义之间的转换的主要难点在于不保函数基调.基于Monad思想推导出的接续语义函数和直接语义函数之间的关系,给出了基于规约的从接续指称语义描述形式到直接指称语义描述形式的转换技术,分别考虑了接续函数在不同情形下的处理.最后给出了转换算法的Haskell实现系统,验证了转换的可行性.     

一种面向无线传感网应用重编程的逻辑式编程语言

无线传感网的发展,使其需要具有高效地更新其上运行的应用软件的能力.为了解决这个问题,提出了一种面向无线传感网应用重编程的逻辑式编程语言及其处理系统ReLog.ReLog语言根据无线传感网应用的普遍特点,基于传统逻辑式语言进行扩展,并提供合适的编程抽象,方便程序员高效地构建、修改程序.同时,语言的处理系统使用中间代码将应用程序与系统软件解耦,从而减少应用更新时所需传输的更新代码的规模,提高更新效率.通过一个数据收集应用案例评估了ReLog语言及其执行机制,结果表明：使用ReLog语言能够获得简洁、易修改的程序;同时,语言的执行机制能够显著降低传输应用更新代码的能量和时间开销.     

使用延时演算的时间化RSL的指称语义

使用扩展的持续时间演算(EDC)模型,给出了时间化的RAISE描述语言(RSL)的一个子集的指称语义.在扩展的持续时间演算模型中加入了一些新的特征,并探究了它们的代数定律.这些定律在形式化实时程序和验证实时性质中起着重要作用.最后还给出了时间化RSL的一些代数定律.这些定律可以从其指称语义证明,并用于程序的转化和优化.     

Denotational semantics of communicating processes based on a language for applicative multiprogramming

The denotational semantics of a simple language for describing tightly coupled ‘synchronous’ systems is defined by translating it into a language for applicative multiprogramming. The applicative language has originally been developed for describing nondeterministic stream-processing functions and loosely-coupled systems of communicating processes. Nevertheless, it can be used after very slight generalizations as a semantic target language for defining the meaning of programs representing tightly-coupled, synchronous systems.     

From algebraic semantics to denotational semantics for Verilog

This paper considers how the algebraic semantics for Verilog relates with its denotational semantics. Our approach is to derive the denotational semantics from the algebraic semantics. We first present the algebraic laws for Verilog. Every program can be expressed as a guarded choice that can model the execution of a program. In order to investigate the parallel expansion laws, a sequence is introduced, indicating which instantaneous action is due to which exact parallel component. A head normal form is defined for each program by using a locality sequence. We provide a strategy for deriving the denotational semantics based on head normal form. Using this strategy, the denotational semantics for every program can be calculated. Program equivalence can also be explored by using the derived denotational semantics. A short version of this paper appeared in Proc. ICECCS 2006: 11th IEEE International Conference on Engineering of Complex Computer Systems [48]. This work is partially supported by the National Basic Research Program of China (No. 2005CB321904), the National High Technology Research and Development Program of China (No. 2007AA010302) and the National Natural Science Foundation of China (No. 90718004). Jonathan Bowen is a visiting professor at King’s College London and an emeritus professor at London South Bank University.     

Equivalence of formal semantics definition methods

There are numerous methods of formally defining the semantics of computer languages. Each method has been designed to fulfil a different purpose. For example, some have been designed to make reasoning about languages as easy as possible; others have been designed to be accessible to a large audience and some have been designed to ease implementation of languages. Given two semantics definitions of a language written using two separate semantics definition methods, we must be able to show that the two are in fact equivalent. If we cannot do this then we either have an error in one of the semantics definitions, or more seriously we have a problem with the semantics definition methods themselves.Three methods of defining the semantics of computer languages have been considered, i.e. Denotational Semantics, Structural Operational Semantics and Action Semantics. An equivalence between these three is shown for a specific example language by first defining its semantics using each of the three definition methods. The proof of the equivalence is then constructed by selecting pairs of the semantics definitions and showing that they define the same language.A full version of this paper can be accessed via our web page http://www.cs.man.ac.uk/fmethods/ facj.html