语义网络表示中变异关系的面向对象实现

在对语义网络表示进行面向对象程序设计时，一个重要的问题是如何描述结点间属性的变异关系，本文主要探讨在Ｃ＾＋＋程序设计语言环境下，语义网络表示中变异关系的实现问题。     

增量静态语义分析的一个对象模型

本文给出了一个对象模型用以描述类ＰＡＳＣＡＬ程序设计语言的静态语义（语义对象，语义依赖）．讨论了基于该模型的增量静态语义分析的过程，动作，并发机制与实现手段．在文章的最后部分对模型扩充讨论了在多用户，分布式环境中的增量语义分析．文中的模型可稍加扩充以适应一般的高级程序设计语言．     

动态模糊逻辑程序设计语言的指称语义

文献[8]借鉴Dijkstra的监督命令程序结构,给出了动态模糊逻辑程序设计语言的基本框架结构.在此基础上,进一步扩充和完善,并根据指称语义的原理和方法,用结构归纳法给出动态模糊逻辑程序设计语言的指称语义,主要包括:动态模糊程序设计语言的语义域、语义函数及其指称语义.最后给出了一个动态模糊程序设计语言的例子以观察程序的运行过程.     

Fortran 90语言中辅程序交叉返回的编译技术

Ｆｏｒｔｒａｎ９０是Ｆｏｒｔｒａｎ语言的最新国际标准。出于对语言兼容性方面的考虑，Ｆｏｒｔｒａｎ９０语言中的辅程序可以有多个出口。该编译系统的目标语言是程序设计语言Ｃ。根据Ｃ语言的语义，在一个函数中只能有一个出口。源语言与目标语言之间存在的语义差距，给编译程序的实现增加了难度。文中着重介绍了Ｆｏｒｔｒａｎ９０语言中辅程序交叉返回的特征及其编译实现的技术。     

Garment中的归约语义

文中用代数方法研究了Ｇａｒｍｅｎｔ中程序设计语言的归约语义，首先给出了归约语义在形式语言理论中的含义，然后提出了Ｇａｒｍｅｎｔ中语言的代数模型。在此代数模型下讨论了归约语义及其性质，并给出了语言可归的充分条件。     

逻辑程序语言

逻辑程序语言又叫说明语言，这是因为用它编写的程序中，说明语句多于赋值语句或流程控制语句。逻辑程序语言的一个最基本的特征是它的语义。研究逻辑程序语言的语义称为说明语义学。具体说就是寻找一种简单的方法来确定每一语句的意义，而该方法与语句将解决的问题无关。第一个逻辑程序语言PROLOG是在70年代初由法国马赛大学的周amC0hnerauer和PhillippeR＿l开发成功的，它的设计技巧由伦敦大学的RobertKOWISki提出。在一般的程序设计系统中，程序告诉计算机的是如何一步一步地去解决问题。而在逻辑程序设计系统中，程序会告诉计算机…     

一种基于Mealy!机的语义程序验证方法

语义验证是束缚语义软件和语义程序设计语言发展的问题之一,针对这一问题,在基于语义Web服务的语义程序设计语言SPL及其知识库业务领域本体(BDO)的基础上,提出了一种基于Mealy!机对SPL所编排的业务过程进行语义验证的方法,结合在线外汇交易平台的案例,详细描述了运用该方法进行语义验证的过程。通过案例证明,本方法有助于编写语义正确的语义程序。     

全国第4次程序设计语言发展与教学学术会议征文通知

全国第4次程序设计语言发展与教学学术会议定于2003年春季在江苏扬州召开。本次会议由东南大学承办，扬州大学、南京大学、武汉大学等院校协办，现将有关事项通知如下: 一、征文范围 程序设计语言历史、现状与发展,面向对象语言及相关技术,各类建模语言及其设计、实现与应用,面向网络应用的程序设计语言(XML、HTML、PERL等),其他各种新型程序设计语言(包括逻辑型语言、函数型语言等),程序设计语言分析、评价与比较,程序设计语言语法、语义与语用以及形式化描述技术与方法,并发、并行与实时程序设计语言,软件开发过程中各类描述语言(包…     

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。     

带迭代算子的函数式程序设计

本文提出了程序设计语言的一种新的计算模型，带迭代处子的函数式模型，文中给出了基于该计算模型的程序设计语言的语法、计算规则集及确定怀证明，该类语言以表达式的复合描述顺序，以迭代表达式描述循环，以条件表达式描述分支，使得程序以数学语义为基础，易于理解，证明及构造高效的执行系统，相信该类语言是一咱有坚实理论基础、高效的、实际有用的高级确定性程序设计语言。     

Deterministic and nondeterministic flowchart interpretations

Programming languages are studied in the abstract. Algebraic theories supply the syntax for programming languages. Semantics is provided by coproduct preserving functors from the algebraic theory to some semantic category with finite coproducts. Deterministic programming languages are provided when the semantic domain is the category of pointed sets and point preserving functions. Nondeterministic programming languages occur when the semantic domain is the category of Abelian monoids. The class of all nondeterministic programming languages with a fixed syntax is shown to be a variety of algebras. All classes of deterministic programming languages that allow branching are shown to be nonvarietal. Other properties of classes of programming languages are studied using category theory.     

Are visual programming languages better? The role of imagery in program comprehension

This paper presents one experiment to explain why and under which circumstances visual programming languages would be easier to understand than textual programming languages. Towards this goal we bring together research from psychology of programming and image processing. According to current theories of imagery processing imagery facilitates a quicker access to semantic information. Thus, visual programming languages should allow for quicker construction of a mental representation based on data flow relationships of a program than procedural languages. To test this hypothesis the mental models of C and spreadsheet programmers were assessed in different program comprehension situations. The results showed that spreadsheet programmers developed data flow based mental representations in all situations, while C programmers seemed to access first a control flow and then data flow based mental representations. These results could help to expand theories of mental models from psychology of programming to account for the effect of imagery.     

C语言的语义特点

C语言是目前最流行的计算机语言之一,它兼有传统高级语言和汇编语言的优点,概念简洁,风格灵活,内涵相当丰富。要真正掌握该语言的精髓和理解其语义并非易事。本文对C语言的语义特点作了深入探讨,并给出了一些重要概念,最后,列举了若干在编程中的常见错误。     

Facet Grammars: Towards static semantic analysis by context-free parsing

Use of executable declarative metalanguages has simplified programming language syntax specification and implementation, whereas existing formalisms for static semantics are still relatively procedural. A working hypothesis is that the context-sensitivity of languages (under static semantic rules) is derived in significant part from the interleaved presences therein of sentences in implicitly-defined and effectively invisible context-free languages. Procedures by which these sentences and context-free grammars for their languages can be respectively derived from the original sentence and the combination of the original language's grammar and semantic rules, lead to the possibility of automatic generation of static semantic analysers from the purely context-free specifications of “Facet Grammars” (FG)!

We show that the utility of FG for static semantic analysis has a non-trivial lower bound, by specifying the relatively complicated identifier scope and accessibility rules for Dijkstra's Guarded Commands Language.     

On the semantics of parsing actions

Parsers, whether constructed by hand or automatically via a parser generator tool, typically need to compute some useful semantic information in addition to the purely syntactic analysis of their input. Semantic actions may be added to parsing code by hand, or the parser generator may have its own syntax for annotating grammar rules with semantic actions. In this paper, we take a functional programming view of such actions. We use concepts from the semantics of mostly functional programming languages and adapt them to give meaning to the actions of the parser. Specifically, the semantics is inspired by the categorical semantics of lambda calculi and the use of premonoidal categories for the semantics of effects in programming languages. This framework is then applied to our leading example, the transformation of grammars to eliminate left recursion. The syntactic transformation of left-recursion elimination leads to a corresponding semantic transformation of the actions for the grammar. We prove the semantic transformation correct and relate it to continuation passing style, a widely studied transformation in lambda calculi and functional programming. As an idealization of the input language of parser generators, we define a call-by-value calculus with first-order functions and a type-and-effect system where the effects are given by sequences of grammar symbols. The account of left-recursion elimination is then extended to this calculus.     

C/C++软件测试工具的元数据结构设计与实现

针对用C/C++语言进行的语义分析,设计一种中间结构,即元数据结构。元数据结构实现了源代码的语义层次上的抽象,通过元数据结构和相关应用语义配置,过滤出源程序中符合应用的语义内容,实现软件测试工具的程序插装等功能。在中间结构实现过程中,构造一个二次解析引擎,以解决传统解析方法的复杂性及不确定性,实现对各种编程语言的支持。     

Aspect and XML-oriented Semantic Framework Generator: SmartTools

SmartTools is a semantic framework generator, based on XML and object technologies. Thanks to a process of automatic generation from specifications, SmartTools makes it possible to quickly develop environments dedicated to domain-specific and programming languages. Some of these specifications (XML, DTD, Schemas, XSLT) are issued from the W3C which is an important source of varied emerging domain-specific languages. SmartTools uses object technologies such as visitor patterns and aspect-oriented programming. It provides code generation adapted to the usage of those technologies to support the development of semantic analyses. In this way, we obtain at minimal cost the design and implementation of a modular development platform which is open, interactive, uniform, and most important prone to evolution.     

There is no fully abstract fixpoint semantics for non-deterministic languages with infinite computations

It is well known that for many non-deterministic programming languages there is no continuous fully abstract fixpoint semantics. This is usually attributed to “problems with continuity”, that is, the assumption that the semantic functions should be continuous supposedly plays a role in the difficulties of giving a fully abstract fixpoint semantics. We show that for a large class of non-deterministic programming languages there is no fully abstract least fixpoint semantics even if one considers arbitrary functions (not necessarily continuous) over arbitrary partial orders (not necessarily complete).