Kent Beck：领导Java敏捷潮

Sun的官方Java教材中有一句话，说Java是“C++的语法与Smalltalk语义的结合”。而Smalltalk的创造者就是Alan Kay。     

Smalltalk并不小

在最新版的VisualAge for Smalltalk中,IBM已修饰和扩展了面向对象的开发系统,但它仍需较长时间和大量计算机资源,用以从VisualAge for Smalltalk 4.0中获得分布式应用程序。而与此同时众多Java工具亦正加紧改进。     

面向对象开发方法的最新进展

面向对象程序设什方法起源于六十年代末期的语言SIMULA’67,到了七十年代末期,软件行业正受到软件危机的困扰,结构化的开发方法不能够很好地解决软件危机。面向对象语言Smalltalk的出现,进一步发展和完善了面向对象的程序设计语言,     

C＋＋多态技术实现反思

面向对象技术最早出现于1960年代的Simula 67系统,并且在1970年代保罗阿托实验室开发的Smalltalk系统中发展成熟。然而对于大部分程序员来说,C 是第一个可用的面向对象程序设计语言。因此,我们关于面向对象的很多概念和思想直接来自于C 。但     

面向对象程序设计语言的形式语义研究

面向对象程序设计语言(以下简称面向对象语言)的基本思想起源于六十年代中期的Simula语言,在七十年代的Smalltalk语言及环境中得到发展,在八十年代的Eiffel、C++等语言中进一步得到巩固和完善。     

从SmalltaIk语言的结构特征看“软插件”的形成

<正> 一、引言软件的可重用性是软件工程领域中的一个重要课题,现已经有许多人在探索软件可重用的途径,面向对象的程序设计方法则是以解决软件可重用性问题作为自己的重要目标之一。另外,Smalltalk语言经过十几年的实践,走向了成熟,开始为广大程序人员所欣然接受,国内已有相当数量的软件工作者开始研究该语言。我们在VAX-11/780机上用C语言实现了Smalltalk-80系统的核心环境,深受Smalltalk语言其独特构造的启发。本文从Smalltalk语言的结构分析出发,提出了“软插件”的概念,并探讨了此概念形成和实用的可能性,以及它在软件可重用领域中的实践意义,最后,讨论了面向对象方法与“软插件”概念的必然联系。     

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。     

基于面向属性(面向对象)概念的对象粒的属性逻辑公式描述

研究基于面向属性概念、面向对象概念的对象粒的属性逻辑公式描述问题,讨论共有属性概念格和面向属性概念格、面向对象概念格的关系,在基于概念格的共有属性分析的对象粒描述方法基础上,给出基于面向属性概念格的可能属性分析的对象粒描述和基于面向对象概念格的必然属性分析的对象粒描述,分析属性逻辑公式语义构成的面向属性概念的外涵、面向对象概念的外涵的属性逻辑公式的结构特征,有助于应用对象粒的属性逻辑公式描述构建面向属性和面向对象的概念格.     

面向对象技术中的“蛋—鸡”问题

本文提出了面向对象技术中的蛋—鸡问题,即面向对象两个核心概念——类和继承之间关系的认识。讨论了从不同角度看待的类和继承性各自的普遍意义,分析了基于两种认识的不同的面向对象方法学及其各自的优缺点,并就Smalltalk和C++两种语言中的继承性理解和类的使用问题进行了讨论。结论是面向对象技术中的蛋—鸡问题非常重要,应当引起面向对象系统用户和设计人员的重视。     

面向对象程序设计的专家系统研究

面向对象程序设计语言(OOP)的特点十分适宜于建造知识库专家系统。本文是在OOP的软件环境Smalltalk/v基础上联系土木工程结构抗震专题探讨建造专家系统过程中的知识表示、推理及人-机界面等关键问题的处理方法。     

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．     

A technique for subclassing and its implementation exploiting polymorphic procedures

Since the introduction of Smalltalk, the object-oriented approach towards the organization of data and programs has become popular. In this paper the possibilities of exploiting procedure-oriented languages to allow an object-oriented style of programming are analysed. Although the two approaches are apparently dissimilar, a family of procedure-oriented languages is described which allows a high degree of freedom in programming and does not appear to restrain the programmer within the procedure-oriented scheme. Popular languages of this family are ML and PS-Algol. For such languages, a technique is developed which enables an efficient implementation of object-oriented features, such as the subclassing form of inheritance provided by Smalltalk-80 and Simula.     

Object management in a persistent smalltalk system

The main goal of the Alltalk project is to provide transparent database support to the Smalltalk programmer. As a first step towards this goal, the current version of Alltalk extends Smalltalk-80 by providing persistence to Smalltalk objects without adding a database sublanguage, new language syntax, classes or methods. This paper describes the implementation of object management in Alltalk, including database layout, database access methods, in-memory object management and high-level interface from the interpreter. It also discusses how the object manager is integrated in a unique way with the operations of the Alltalk garbage collector and interpreter.     

SPiCE: a system for translating Smalltalk programs into a Cenvironment

Smalltalk-80 (hereafter referred to as Smalltalk), which is one of the most productive programming languages/environments, is very well suited for prototyping of applications but it is less well suited for delivering applications because applications can neither run in isolation from the Smalltalk environment nor be combined with other programs written in other languages. One way to make Smalltalk suitable for delivering applications is to translate Smalltalk into a compiler language such as C. By translating Smalltalk code into portable and interoperable C code, it is possible to deliver a stand-alone version of Smalltalk applications, and to develop an application partly in Smalltalk and partly in C. However, there are some difficulties in translating Smalltalk code into such a C code. First, the execution model of Smalltalk, which creates activation records as objects, is very different from that of C, and second, Smalltalk and C have very different approaches to storage management. We have implemented SPiCE, a system for translating Smalltalk into C. Our approach to the translation is to create runtime replacement classes implementing the same functionality of Smalltalk classes that are inherently part of the Smalltalk execution model, and to provide semi-conservative real-time compacting garbage collection that works without language support     

型构兼容的继承及其语义

本文揭示了在面向对象程序设计语言中,若劲旅子类重定义其继承的分类方法以发迹这些方法的规约,并且采用类似于Ｓｍａｌｔａｌｋ－８０中的继承机制的语义,将导致封将与继承之间的一个新总是为此,本文提出了一种新的继承机制－型构兼容的继承,以代替传统的增量继承。型构兼容的继承是一种灵活的代码复用机制,并且能够充分支持封装。     

A visual query language for graphical interaction withschema-intensive databases

This paper presents a visual query language called VQL for interacting with an object-oriented schema-intensive data model. VQL allows convenient access to the various types of knowledge captured by the semantic model. It consists of a set of “graphical primitives” along with a combination grammar for creating graphical queries. The visual language is internally supported by a prolog-like predicate based query language. The formal grammar underlying the predicate based language is also presented. Apart from being able to create simple queries that can be specified in SQL or QBE, VQL can be used for making queries on any object-oriented data model including the generalization of the E-R model. VQL also handles complicated, indirect queries, specially those that require a reasoning system for query interpretation and response generation. Further, recursive queries on graph structures such as finding transitive closures of graphs may be easily specified. Perhaps the most powerful feature of VQL is its ability to provide high semantic expressibility (in being able to specify highly complex queries) while maintaining simplicity in the user's query formulation process. VQL is embedded in an object-oriented graphical database interaction environment that supports schema creation and manipulation in addition to database querying and updation. The prototype has been implemented in Smalltalk-80 running on a Sun 3/60 workstation. All the illustrations of visual interaction presented are taken from actual interaction sessions     

Object-oriented intelligent computer-integrated design, processplanning, and inspection

The methodology for developing intelligent integrated computer-aided design and manufacturing systems based on object-oriented principles is discussed. The ways in which the application of these principles affects the nature of these systems are reviewed. The implementation of an automated, intelligent, and flexible computer-integrated-manufacturing (CIM) system prototype using an object-oriented programming environment (Smalltalk-80, Version 4.0) is detailed. A CIM system includes CAD, a process planner, and an inspection planner. Each of these components is discussed individually     

Smalltalk的汉字信息处理

Ｓｍａｌｌｔａｌｋ是最具有代表性的面向对象的程序设计语言及环境。本文给出了在其中实现汉字信息处理的一种方法。此方法不是对原系统进行汉化，而是针对Ｓｍａｌｌｔａｌｋ的完成输入，输出及编辑功能的类程设置相应的汉字处理类程，使用户不但能在各窗口中处理汉字信息，而且也能在程序中输出汉字。文中首先分析了Ｓｍａｌｌｔａｌｋ的字符显示原理及窗口技术，然后详述了各汉字类程的设计思想和实现方法。     

An object-oriented class library for C++ programs

The Object-Oriented Program Support (OOPS) class library is a portable collection of classes similar to those of Smalltalk-80 that has been developed using the C++ programming language under the UNIX operating system. The OOPS library includes generally useful data types, such as String, Date and Time, and most of the Smalltalk-80 collection classes such as OrderedCtn (indexed arrays), LinkedList (singly linked lists), Set (hash tables), and Dictionary (associative arrays). Arbitrarily complex data structures comprised of OOPS and user-defined objects can be stored on disk files or moved between UNIX processes by means of an object I/O facility. The classes Process, Scheduler, Semaphore and SharedQueue provide multiprogramming with coroutines. This paper gives a brief introduction to object-oriented programming and how it is supported by the C+ + programming language. An overview of the OOPS library is also presented, followed by a programming example. The implementation details of two of the class library's more interesting features, object I/O and processes, are described. The paper concludes with a discussion of the differences between the OOPS library and Smalltalk-80 and some observations based on our programming experience with C++ and OOPS.